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DICTIONARY OF

ARCHITECTUR

AND

CONSTRUCTION

FOURTH EDITION

DICTIONARY OF
ARCHITECTURE &
CONSTRUCTION

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DICTIONARY OF
ARCHITECTURE &
CONSTRUCTION

2300 illustrations

Fourth Edition

Edited by

Cyril M. Harris

Professor Emeritus of Architecture

Graduate School of Architecture, Planning, and Preservation

Columbia University

McGraw-Hill

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DOI: 10.1036/0071452370

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This book is dedicated to the memory of Adolph K. Placzek,
Avery Librarian at Columbia University, whose leadership
made Avery Library one of the world's greatest collections
on architecture. I am grateful to him for long and fruitful
discussions, for his exemplary scholarship, and for the
generosity of spirit with which he shared his experience, his
wisdom, and the gift of his friendship.

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PREFACE

This Fourth Edition of the Dictionary of Architecture & Construction defines more terms in
architecture and building construction than any other dictionary in the English language.
Because there have been significant changes, advances, and new developments in building
materials and services, construction techniques, engineering practices, specifications writing,
environmental concerns, community regulations, legal requirements, and other areas over
the last decade, a total of 2500 new terms, as well as 100 new illustrations, have been
added to this edition. This coverage provides an up-to-date working tool for practicing
professionals in the many fields and numerous trades related to architecture and construction,
as well as an invaluable resource for conservationists, planners, architectural historians,
and students.

The Dictionary is designed to be comprehensive in scope. Its range spans terms encountered
in the practice of architecture from Classical to green, from traditional materials to the
latest products, from precise definitions of architectural styles to the particulars of
specifications writing. Many of the new terms are associated with major expansions in the
field of building services, including air-conditioning systems, electrical supply systems, gas
supply services, illumination engineering, noise control engineering, vertical transportation
systems, security services, and waste disposal, water supply, and fire protection systems.
Other definitions pertain to environmental concerns, conservation, building preservation,
community regulations, and recent applications of the Americans with Disabilities Act.
Equivalent values in Standard International units are given for U.S. Customary units.

Cyril M. Harris

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ACKNOWLEDGMENTS

The editor owes a special debt to the core group of 54 contributors who helped
establish the high standard of quality of the Dictionary; coming from widely diverse
backgrounds, including practicing architects, professional engineers, specification writers,
craftsmen, contractors, and art historians, they provided the necessary expertise required
for a comprehensive, authoritative work. I thank Walter F. Aikman; William H. Bauer;
Bronson Binger, AIA; Donald Edward Brotherson, AIA; Robert Burns, AIA; A. E. Bye,
EA.S.LA.; Richard K. Cook, Ph.D.; William C. Crager, C.S.P.; Frank L. Ehasz, Ph.D., PE;
Francis Ferguson, AIA, AIP; Frederick G. Frost, FAIA; Alfred Greenberg, PE; John
Hagman; Michael M. Harris, FAIA; R. Bruce Hoadley, D.For.; Jerome S. B. Iffland, PE;
George C. Izenour, AIEEE; Curtis A. Johnson, M.Sc, PE; Edgar Kaufmann, Jr., HAIA;
Thomas C. Kavanaugh, Sc.D.; Robert L. Keeler; George Lacancellera, CSI; Paul Lampl,
M.A., AIA; Valentine A. Lehr, M.S.C.E., PE; Robert E. Levin, Ph.D., PE; George W
McLellan; Emily Malino, AID; Roy J. Mascolino, R.A.; Donald E. Orner, PE; John Barratt
Patton, Ph.D.; Adolf K. Placzek, Ph.D.; Albert J. Rosenthal, L.L.B.; Henry H. Rothman,
F.F.C.S.; James V. Ryan, M.S.; John E. Ryan, PE, S.F.P.E.; Reuben Samuels, PE, F.A.S.C.E.;
Joseph Shein, AIA; Joseph M. Shelley, B.SArch.; Kenneth Alexander Smith, AIA, PE;
Perry M. Smith, PE; Fred G. Snook, M.S.; Carl A. Swanson, B.C.E., CSI; Kenneth
Thomas, M.Sc, C.Eng.; Charles W Thurston, Ph.D., PE; Marvin Trachtenberg, Ph.D.;
Everard M. Upjohn, M.Arch.; Oliver B. Volk; and Byron G. Wels.

I would like to express my appreciation to the following organizations for permission to
reproduce selected definitions and/or illustrations from certain copyrighted publications:
the American Institute of Architects for selected definitions from the AIA Glossary of
Construction Industry Terms; the American National Standards Institute (ANSI) and the
American Society for Testing and Materials (ASTM) for material from the ASTM Book
of Standards; and the British Standards Institution for extracts from publications BS 56,
BS 3921, and CP 121. Further reproduction is not permitted without the explicit per-
mission of these copyrighted sources.

Permission has also been granted to reproduce material from the following publications:
The Asphalt Handbook of the Asphalt Institute; Facts and Figures of the Pioneer Division,
Portec Inc.; CPM in Construction: A Manual for General Contractors of the Association of
General Contractors of America; Brick and Tile Engineering by H. C. Plummer, Structural
Clay Products Institute; Ceramic Glossary of the American Ceramic Society; Plastics Glossary
of Modern Plastics magazine, published by McGraw-Hill; Timber Construction Manual of the
American Institute of Timber Construction, published by John Wiley & Sons; Wood-
working Technology by J. J. Hammond et al., published by McKnight & McKnight; Funda-
mentals of Business Law, published by Callaghan & Co.; Product Line Dictionary, published by
the Canadian Construction Information Corp.; Glossary of Architectural Metal Terms of the
National Association of Architectural Metal Manufacturers; ASCE Manual of Engineering
Practice; and Guide and Data Books, published by ASHRAE.

I thank the following organizations for their permission to reproduce definitions and/or
illustrations from their publications: Aluminum Association; American Institute of Steel
Construction; American Iron and Steel Institute; Architectural Aluminum Manufacturers
Association; Copper Development Association; Revere Copper and Brass Co.; The Steel
Company of Canada; Steel Joist Institute; Zinc Institute, Inc.; National Fire Protection

Association; Illuminating Engineering Society; National Builder's Hardware Association;
and American Concrete Institute (ACI) and ACI Committees. Further reproduction
requires permission from the above organizations. Certain other organizations and
publications have authorized reproduction of definitions or illustrations without formal
acknowledgment. I thank William A. Pierson for permission to reproduce his photograph
of Round Arch style.

I acknowledge the help of and thank Cary Sullivan, senior editor for architecture, design,
and construction books, McGraw-Hill Professional. At International Typesetting and Com-
position, whose task it was to work with the publisher to move the Dictionary from manuscript
to printed book, I thank Mona Tiwary for her exemplary diligence.

ABOUT THE EDITOR

Cyril M. Harris, Ph.D., is Professor Emeritus of Architecture in the Graduate School of
Architecture, Planning, and Preservation at Columbia University, where he was chairman
of the Division of Architectural Technology for 10 years. He is also the Charles Batchelor
Professor Emeritus of Electrical Engineering at Columbia. He became fascinated by the
challenge of writing succinct, lucid definitions many years ago, when he was working on
Committee C-20 of the American Society for Testing and Materials (ASTM), as well as
on terminology committees of the American Standards Association (now called the
National Institute of Standards and Technology [NIST]).

Dr. Harris has received the AIA Medal from the American Institute of Architects and
the Pupin Medal for Distinguished Service to the Nation from Columbia University. He is
a member of both the National Academy of Sciences and the National Academy of Engi-
neering. He has received international recognition for his work in the acoustical design of
many auditoriums, including the Metropolitan Opera House and the John F. Kennedy
Center for the Performing Arts. He has a Ph.D. in physics from the Massachusetts Insti-
tute of Technology and has received honorary doctorates from Northwestern University
and the New Jersey Institute of Technology.

Other books on architecture written or edited by Dr. Harris include American Archi-
tecture: An Illustrated Encyclopedia (W. W. Norton & Company), Illustrated Dictionary
of Historic Architecture (Dover Publications), and Acoustical Designing in Architecture
(Acoustical Society of America). Seven of his books are currently in print.

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A Abbr. for angstrom.

A 1. Abbr. for ampere, a unit of electric current.
2. Abbr. for area.

AA Abbr. for the "Architectural Association,"
the largest school of architecture in England;
address 34-36 Bedford Square, London, WC1B
3ES.

AAA Abbr. for "Architectural Aluminum Asso-
ciation."

AAI Abbr. for "Architectural Association of
Ireland."

AAMA Abbr. for "Architectural Aluminum
Manufacturers Association."

A&E See architect-engineer.

Aaron's rod An ornament or molding consist-
ing of a straight rod from which pointed leaves
or scroll work emerge on either side, at regular
intervals.

ABA Abbr. for Architectural Barriers Act.

abaciscus 1. A tessera, as used in mosaic work.

Also called abaculus. 2. A small abacus.
abaculus See abaciscus, 1 .

abacus The uppermost member of the capital of
a column; often a plain square slab, but some-
times molded or otherwise enriched.

abamurus A buttress, or a second wall added to
strengthen another.

abate l.To remove material, as in stone carv-
ing. 2. In metalwork, to cut away or beat down
so as to show a pattern or figure in low relief.

abated Said of a surface that has been cut away
or beaten down so as to show a pattern or figure
in low relief; also see relief.

abatement The wastage of wood when lumber
is sawed or planed to size.

abat-jour 1 . In a wall, an aperture whose sides
have been cut back and/or whose underside has
been sloped downward so as to admit a greater
amount of light to the interior of the room. 2. A
skylight.

abaton A sanctuary not to be entered by the
public; a holy of holies.

abat-sons Descriptive of a surface said to reflect
sound downward.

abat»vent 1 . Louvers that are placed in an exte-
rior wall opening to permit light and air to enter,
but break the wind. 2. A sloping roof. 3. In the
French Vernacular architecture of New Orleans,
an extension of a roof over a sidewalk.

abat'voix

abat-voix In a church, a sound reflector behind
and over a pulpit.

abat

abat-voix

abbey A monastery or convent; particularly the
church thereof.

abbey: Plan of abbey of St. Germain-des-Pres, Paris, 13th
cent. A, church; B, cloister; C, city gate; E, chapter house;
F, chapel; G, refectory; H, cellars and presses; J, abbot's lodg-
ing; K, ditches; L, gardens

abbreuvoir Same as abreuvoir.

ABC l.Abbr. for "aggregate base course."
2.Abbr. for "Associated Builders and Con-
tractors."

A»block A hollow, concrete masonry unit with
one end closed and the opposite end open, having

a web between, so that two cells are formed
when the block is laid in a wall.

Abney level A hand level used for measuring
vertical angles; comprised of a small telescope,
bubble tube, and graduated vertical arc.

above-grade building volume The volume
of a building (in cubic feet or in cubic meters)
measured from the average adjoining grade level
to the average roof level, and from outside to
outside of exterior walls, but not including
breezeways, porches, or terraces.

abrade To wear away or scrape off a surface,
especially by friction.

Abrams' law A statement applying to given
concrete materials and conditions of test: For a
mixture of workable consistency, the strength of
concrete provided by the mixture is determined
by the ratio of the amount of water to the
amount of cement.

abrasion A surface discontinuity caused by
roughening or scratching.

abrasion resistance The ability of a surface
to resist being worn away or to maintain its orig-
inal appearance when rubbed with another
object.

abrasion resistance index A measure of the
abrasion resistance of a vulcanized material or
synthetic rubber compound relative to that of
a standard rubber compound under specified
conditions.

abrasive A hard substance for removing mate-
rial by grinding, lapping, honing, and polish-
ing. Common abrasives include silicon carbide,
boron carbide, diamond, emery, garnet, quartz,
tripoli, pumice, diatomite, metal shot, grit, and
various sands; usually adhered to paper or
cloth.

abraum A red ocher used to stain mahogany.

abreuvoir In masonry, a joint or interstice
between stones, to be filled with mortar or
cement.

ABS Abbr. for acrylonitrile-butadiene-styrene.

abscissa In the plane Cartesian coordinate sys-
tem, the horizontal coordinate of a point on a
plane; the x-coordinate, obtained by measuring
the distance from the point to the y-axis along a
line parallel to the x-axis.

absorption field

■x

abscissa: P, any point; NP, abscissa

abside Same as apse.

absidiole Same as apsidiole.

absolute humidity The mass of water vapor
per unit volume of air.

absolute pressure The sum of the gauge pres-
sure plus atmospheric pressure.

absolute volume l.Of a granular material, the
total volume of the particles, including the perme-
able and impemieable voids, but excluding the
spaces between the particles. 2. Of fluid, the vol-
ume which the fluid occupies. 3. The displacement
volume of an ingredient of concrete or mortar.

absorbed moisture Moisture that has entered
a solid material by absorption and has physical
properties not substantially different from ordi-
nary water at the same temperature and pressure.
Also see absorption.

absorbency The property of a material that
measures its capacity to soak up liquids.

absorbent A material which, owing to an affin-
ity for certain substances, extracts one or more
such substances from a liquid or gas with which
it is in contact, and which changes physically or
chemically, or both, during the process.

absorber 1 . A device containing liquid for absorb-
ing refrigerant vapor or other vapors. 2. In an
absorption system, that part of the low-pressure
side of the system which is used for absorbing refrig-
erant vapor. 3. That part of a solar collector whose
primary function is to absorb radiant solar energy.

absorber plate Same as solar collector.

absorbing well, dry well, waste well A

well used for draining off surface water and con-
ducting it underground, where it is absorbed.
absorptance In illumination engineering, the
ratio of the absorbed flux to the incident flux.

absorption 1. The process by which a liquid, or a
mixture of gases and liquid, is drawn into and tends
to fill permeable pores in a porous solid material;
usually accompanied by a physical change, chemi-
cal change, or both, of the material. 2. The
increase in weight of a porous solid body resulting
from the penetration of liquid into its penneable
pores. 3. The increase in weight of a brick or tile
unit when immersed in either cold or boiling water
for a stated length of time; expressed as a percent-
age of the weight of the dry unit. 4. The process by
which radiant energy, which is incident on a
surface, is converted to other forms of energy.
5. See sound absorption. 6. See light absorption.

absorption bed A pit of relatively large
dimensions which is filled with coarse aggregate
and contains a distribution pipe system; used to
absorb the effluent of a septic tank.

absorption coefficient See sound absorption
coefficient.

absorption field, disposal field A system of
trenches containing coarse aggregate and distri-
bution pipes through which septic-tank effluent
may seep into the surrounding soil.

absorption field composed of absorption trenches

Extent of coarse aggregate indicated by shaded area

absorption rate

absorption rate, initial rate of absorption

The weight of water absorbed when a brick is par-
tially immersed for one minute; usually expressed
in grams per minute or ounces per minute.

absorption system A refrigeration system in
which the refrigerant gas evolved in the evapo-
rator is taken up in an absorber and (upon the
application of heat) released in a generator.

absorption trench A trench containing coarse
aggregate and a distribution tile pipe through
which septic-tank effluent may flow, covered
with earth.

IMPERVIOUS MATERIAL

FILTER MATERIAL r^r .,:

OPEN JOINT TILE
OR PERFORATED PIPE

absorption trench

absorption-type liquid chiller Equipment
utilizing a generator, condenser, absorber, evapo-
rator, pumps, controls, and accessories to cool
water, or other secondary liquid, using absorp-
tion techniques.

ABS plastic A plastic of acrylonitrile-butadiene-
styrene; has good resistance to impact, heat, and
chemicals; esp. used for piping.

abstract of title An outline history of the own-
ership of a parcel of land, from the original
grant, with changes in title, and with a state-
ment of all mortgages, liens, encumbrances, etc.,
affecting the property.

abut To adjoin at an end; to be contiguous.

abutment A masonry mass (or the like) which
receives the thrust of an arch, vault, or strut.

W"V

abutment piece See solepiece.

abuttals Those boundaries of one piece of land
that abut on adjacent pieces.

abutting joint A joint between two pieces of
wood, in which the direction of the grain in one
piece is at an angle (usually 90°) to the grain in
the other.

abutting tenon One of two tenons which are
inserted in a common mortise from opposite
sides, so as to touch each other.

ac, a-c, a.c. Abbr. for "alternating current."

AC 1. On drawings, abbr. for "alternating current."
2. On drawings, abbr. for armored cable. 3. Abbr.
for air conditioning. 4. Abbr. for "asbestos cement."

acacia Same as gum arabic.

Acadian cottage Same as Cajun cottage.

acanthus A common plant of the Mediter-
ranean, whose leaves, stylized, form the charac-
teristic decoration of capitals of Corinthian and
Composite orders. In scroll form it appears on
friezes, panels, etc.

abutment A

acanthus

ACB l.Abbr. for asbestos-cement board. 2.

Abbr. for "air circuit breaker."

accelerated aging The speeding-up of the
aging process in a material; obtaining, in a
short time, the results that would occur in aging
under normal conditions. The most common
factors that increase aging include exposure of
the material to water, ozone, oxygen, or sun-
light.

accelerated life test A test in which one or
more parameters (e.g., temperature) is increased
or decreased beyond its normal or rated value to
determine the resulting deterioration within a
reasonable time period.

accelerated weathering A laboratory testing
technique to determine, in a relatively short
time, the weather resistance of a paint film or
other exposed surface.

accessory use

accelerating admixture An admixture that
speeds the setting and/or the early strength
development of hydraulic concrete.

acceleration l.The rate of change of the
velocity of a moving body. 2. The rate of change,
esp. the quickening of the natural progress of a
process, such as hardening, setting, or strength
development of concrete.

acceleration of gravity (g) The acceleration
produced by the force of gravity at the surface of
the earth. (By international agreement the value
of g is 386.089 inches per second square =
32.1740 feet per second square = 9.80665 meters
per second square.)

acceleration stress In a wire rope (or the
like), the additional stress imposed as a result of
the acceleration of the load.

accelerator l.A substance which, when added
to concrete, mortar, or grout, increases the rate of
hydration of a hydraulic cement, shortens the
time of set, or increases the rate of hardening or
strength development. 2. A substance, added with
a curing agent, to speed a vulcanization process
and enhance the physical properties of a vulcan-
ized material. 3. Same as accelerating admixture.

accent lighting Any directional lighting which
emphasizes a particular object or draws attention
to a particular area.

acceptable air quality Inside a building, air
that is free of harmful concentrations of contam-
inants and that is judged acceptable to at least
80% of the building's occupants.

acceptable water pressure See maximum
acceptable pressure and minimum acceptable
pressure.

acceptance See final acceptance.

acceptance test A test conducted by a pur-
chaser (or an agent thereof) (a) to determine if
the material, devices, or equipment delivered
conforms to the purchase contract specifications
and/or (b) to determine the degree of uniformity
of the product supplied by the vendor.

access A means of approach, e.g., a road, street,
or walk.

access door A door, usually small, which is
provided through a finished construction, as
into a duct, through a ceiling, behind a wall, in a
large piece of mechanical equipment, etc.; used
to provide a means of inspection of equipment
or services housed within.

access door

access eye See cleanout, 1.
access floor Same as raised floor,
access flooring system See raised flooring
system.

accessibility standards See Americans with
Disabilities Act and Uniform Federal Accessibility
Standards.

accessible 1. Allowing physical contact, as by
means of an easily removable cover or door or a
part of the building structure or finish materials.

2. Providing access to a fixture, appliance, or
piece of equipment; removal of a cover, panel,
plate, or similar obstruction may be required.

3. Said of a building, facility, or site that can be
approached, entered, and used by a physically
disabled person. 4. According to the Americans
with Disabilities Act (ADA), a term used for a space
that complies with the standards of the Act for
those having disabilities or impairments (including
visual, hearing, mental, or mobility), and does not
require the assistance of others to enter the space.

accessible means of egress A path of travel,
usable by a mobility-impaired person, that leads
to a public way.

accessible route According to the ADA, a
continuous, unobstructed path between all
accessible elements and areas of a building,
including corridors, ramps, and elevators; the
route must provide adequate clearance around
desks, furniture, and the like.

accessible space A space that complies with all
provisions of the Americans with Disabilities Act.

accessory building A secondary building,
whose use is incidental to that of the main build-
ing located on the same plot.

accessory use The use or occupancy incidental
to the principal use or occupancy of a building.

access panel

access panel A removable panel (usually secured
with screws) in a frame which is usually mounted in
a ceiling or wall; provides access to a concealed item
that does not require frequent attention.

access plate A removable plate (usually bolted
in place) that provides access to an area that sel-
dom requires attention; permits inspection of an
otherwise inaccessible area.

access platform Same as cherry picker.

access stair A stair, from one floor level to
another, which does not serve as a required exit
stair. Also see exterior stair.

access street A low-traffic -volume street, usu-
ally comprised of individual dwelling units,
which conveys vehicular traffic to or from a
street carrying heavier traffic.

access way A roadway, usually paved, intended
to provide ingress and egress of vehicular traffic
from a public right-of-way to an off-street parking
area.

accident A sudden, unexpected event identifi-
able as to time and place. Also see occurrence.

accidental air See entrapped air.

acclivity The upward slope of a hillside.

accolade An ornamental treatment, used over
an arch, a door, or a window, composed of two
ogee curves meeting in the middle; often a richly
decorated molding.

olade

accompaniment A decoration added to a
building with the intention of enhancing its
appearance.

accordion door l.Any fabric-faced door
which is hung from an overhead track and folds
back like the bellows of an accordion. 2. A hinged

door consisting of a system of panels which are
hung from an overhead track. When the door is
open, the faces of the panels close flat against
each other; when the door is closed, the edges of
adjacent panels butt against (or interlock with)
each other to form a solid barrier.
accordion partition A fabric-faced partition
which is hung from an overhead track and folds
back like the bellows of an accordion.

accouplement The placement of columns or
pilasters close together, in pairs.

accouplement

accrued depreciation l.The reduction in
actual value of property over a period of time, as
a result of wear and tear, obsolescence, etc. 2.
The accumulated reductions in the stated value
of property over a period of time, entered on bal-
ance sheets for accounting or tax purposes.

accumulator 1 . In a refrigeration system, a
storage chamber for low-side liquid refrigerant;
also called a surge drum or surge header. 2. In a
refrigerant circuit, a vessel whose volume is used
to reduce pulsation.

ACD Abbr. for automatic closing device.

ACE Abbr. for "Architects Council of Europe."

acetone A highly flammable solvent which
evaporates rapidly; used in lacquers, paint
removers, thinners, etc.

acoustic

acetylene A colorless gas, when mixed with
oxygen, burns at a temperature of about 3500°C;
used in welding.

acetylene torch A torch, used in welding and
in metal cutting, which is operated by com-
pressed acetylene gas and oxygen.

AC generator A generator which produces
alternating current when driven by a prime
mover.

Achaemenid architecture An architecture
developed under the Achaemenid rulers of
Persia (6th to 4th cent. B.C.) by a synthesis and
eclectic adaptation of architectural elements
which included those of surrounding countries.
In the hypostyle hall it achieved a highly origi-
nal new building type.

achromatic Said of architecture that is with-
out color, for example, the white buildings of
Greek Revival.

achromatic color White light; a color that
does not elicit hue.

ACI Abbr. for "American Concrete Institute."

acid»etched Said of a metallic surface (e.g., a
nail) that has been treated in an acid bath to
provide a rough surface.

acidic Said of igneous rocks containing more
than 65% silica.

aciding The light etching of a cast-stone
surface.

acid lead Fully refined lead to which a small
amount of copper has been added; 99.9% pure.

acid neutralizer A device installed in a
drainage system into which the discharge of

Outlet-*- 1

nWT"*

level

I ot

"1 I chips

, Battle

g?^

attsfi

acid neutralizer

Limestone

tfipj
\\\ basin

acid is probable; neutralizes the discharge suffi-
ciently to permit it to enter the drainage system
safely.

acid polishing The polishing of a glass surface
by acid treatment.

acid resistance The degree to which a surface,
such as porcelain enamel, will resist attack by
acids.

acid-resistant brick Brick suitable for use in
contact with chemicals; usually laid with acid-
resistant mortars.

acid-resistant cast-iron pipe A cast-iron
pipe containing between 14-25 and 15% silicon
and small amounts of manganese, sulfur, and car-
bon; manufactured in the same dimensions as
cast-iron pipe.

acid soil Soil having an acid reaction; usually a
soil having a pH value of less than 6.6.

acisculis A mason's small pick, with a flat face
and pointed peen.

acorn A small ornament in the shape of a nut of
the oak tree; sometimes used as a finial, pendant,
or decorative element within a broken pedi-
ment, or as a decoration on a carved panel.

acous l.Abbr. for acoustical. 2. Abbr. for
acoustics.

acoustic, acoustical The qualifying adjec-
tives acoustic and acoustical have the following
meanings: arising from, actuated by, containing,
producing, or related to sound. In general,
acoustic is used when the term being qualified
designates something that has the properties,
dimensions, or physical characteristics associated

acoustical barrier

with sound waves; acoustical is used when the
term being qualified does not explicitly desig-
nate something that has the properties, dimen-
sions, or physical characteristics of sound (e.g.,
acoustical engineering). However, sometimes
these two terms are used interchangeably.

acoustical barrier See sound barrier.

acoustical board See acoustical ceiling board.

acoustical ceiling A ceiling covered by, or
formed of, an acoustical material.

acoustical ceiling board An acoustical mate-
rial in board form, designed primarily for sus-
pended ceiling application.

acoustical ceiling system A structural sys-
tem for supporting an acoustical ceiling; may
incorporate lighting fixtures and air diffusers.

■CHANNEL CLIPS
CHANNEL

FIBERGLASS
"BLANKET

PERFORATED
METAL PAN

T-BARS

acoustical ceiling system

acoustical door A solid, heavy door which is
gasketed along the top and sides; usually has an
automatic door bottom; especially constructed
to reduce noise transmission through it; usually
carries a sound transmission class (STC) rating,
which is a measure of its sound insulation value.

acoustical duct lining See duct lining.

acoustical insulation board A porous mate-
rial in board form, designed or used as an acousti-
cal material or as an element in a sound- insulation
construction.

acoustical lay-in panel An acoustical ceiling
board designed to be laid into an exposed grid
suspension system.

acoustical material Any material especially
designed to absorb sound.

acoustical model A model of an auditorium
or room used to study certain acoustical proper-
ties of the full-sized enclosure, such as the distri-
bution of sound pressure, the paths of sound rays,
and focusing effects.

acoustical panel Same as acoustical lay-in
panel.

acoustical plaster A special low-density sound-
absorptive plaster, applied in the form of a finish-
coat, to provide a continuous finished surface.

acoustical power See sound power.

acoustical sprayed-on material An acous-
tical material applied by a spray process to form
a continuous finished surface.

acoustical tile An acoustical material in board
form, often having unit dimensions of 24 in. by
24 in. (approx. 61 cm by 61 cm) or less. Usually
used on ceilings but also may be applied to side-
walls.

acoustics l.The science of sound, including
the generation, transmission, and effects of
sound waves. 2. The totality of those physical
characteristics of an auditorium or room (such as
the size and shape of elements on the walls or
ceiling which scatter sound, the amount of
sound absorption, and noise level within the
room) which affect an individual's perception,
and judgment, of the quality of speech and music
produced in the room.

acph Abbr. for "air changes per hour."

acquiescence 1 . An act of concurrence by
adjoining property owners which resolves a
boundary dispute or establishes a common
boundary, where the definite or more accurate
position of same has not or cannot be defined by
survey. 2. The tacit consent of one owner, by not
interposing a formal objection, to what might
be an encroachment by an adjoining property
owner over a questionable boundary.

acre A unit of land measurement equal to
43,560 sq ft or 4046.85 sq m; 1 sq mile (2.59 sq
km) equals 640 acres.

acre-foot The amount of water required to
cover an area of 1 acre to a depth of 1 foot;
equivalent to 43,560 cubic feet (4046.9 m 3 );
sometimes used as a measure of materials in
place (e.g., gravel).

acrolith A statue or sculptured figure in which
only the head, hands, and feet are of stone, the
rest being usually of wood.

acropodium 1. An elevated pedestal bearing a
statue, particularly if raised from the substruc-
ture on supports. 2. The plinth of a statue if rest-
ing on supports.

acting level

acropolis 1. The elevated stronghold of a Greek
city, usually with the temple of the patron divinity.
2. (cap.) The Acropolis of Athens. 3. Any ele-
vated group of buildings serving as a civic symbol.

acropolis: Acropolis at Athens. A, Propylaea; B, Temple of

Nike Apteros; C, Parthenon; D, Erechtheum; E, foundations

of old Temple of Athena 6th cent. B.C.

acroterion, acroter, acroterium 1. Strictly,
a pedestal at the corners or peak of a roof to sup-
port an ornament. 2. More usually, the ornament
itself.

acroterion, 1

wmmm.

acroterion, 2

acrylic carpet A carpet having a combination
of acrylic and modacrylic fibers; known for its
stain-resistant qualities, high durability, and
wool-like appearance.

acrylic fiber A synthetic fiber manufactured
by polymerizing acrylonitrile.

acrylic paint A type of latex paint made from
acrylic resins; also called acrylic latex paint.

acrylic resin, acrylate resin One of a group
of thermoplastic resins made from esters of
acrylic acid; exceptionally tough, stable, resis-
tant to chemicals, and transparent; used as a
binder, in sheet form, as an air-curing adhesive,
and as the main ingredient in some caulks and
sealants.

acrylonitrile-butadiene-styrene (ABS) A
plastic used for piping in drainage systems, storm
sewers, and underground electrical conduit.

ACS Abbr. for "American Ceramic Society."

ACT. On drawings, abbreviation for "actual."

act curtain, act drop, front curtain, house
curtain A curtain, behind the asbestos cur-
tain in a theater, which closes the proscenium
and serves as an indication of the beginning or
end of an act or scene.

act drop See act curtain.

acting area That part of a theater stage floor on
which the actors perform.

acting area light A spotlight used to illumi-
nate a selected acting area.

acting level A platform above the theater stage
floor which is used for acting.

actinic glass

actinic glass A glass having a yellow tint
which reduces the transmission of infrared and
ultraviolet rays; sometimes used in factory win-
dows or skylights.

action hinge Same as double-acting hinge.

activated alumina A form of aluminum oxide
which adsorbs moisture readily and is used as a
drying agent.

activated carbon See activated charcoal.

activated charcoal, activated carbon Char-
coal obtained by carbonizing organic material,
usually in the absence of air; usually in gran-
ular or powdered form; highly effective in adsor-
bing odors in air or in removing colors in
solution.

activated rosin flux A flux having a resin or
rosin base and containing an additive to increase
wetting by the solder.

activated sludge Sewage sediment that has
been subjected to vigorous aeration and the
action of microorganisms.

activator Same as catalyst.

active door In a pair of doors, the leaf, 1 that is
the first to open and is the leaf to which a lock is
applied.

active earth pressure The component of
pressure in a horizontal direction which a mass
of earth exerts on a wall.

active lateral pressure The horizontal soil
pressure which is exerted by soil on a retaining
structure.

active leaf, active door In a door having a
pair of leaves, that leaf to which the latching or
locking mechanism is attached; usually the leaf
that is permitted to open first; sometimes both
leaves are active.

active sludge A sludge, 3 which is rich in
destructive bacteria; useful in breaking down
fresh sewage.

active solar energy system A building sub-
system in which solar energy is collected and is
transferred predominantly by mechanical equip-
ment (fans, pumps) powered by energy not
derived from solar radiation. Compare with pas-
sive solar energy system.

active sound attenuator A special type of
sound attenuator that incorporates a sound
source which generates sound waves intended to

cancel some of the noise generated by the fans in
an HVAC system.

activity In CPM terminology, a task or item of
work that must be performed in order to com-
plete a project.

activity duration In CPM terminology, the
amount of time estimated as required to accom-
plish an activity.

actual start of construction The first place-
ment of permanent construction of a building on
a site, such as pile driving, or the pouring of slabs
or footings.

acuminated Finished in a point, as a lofty
Gothic roof.

acute angle An angle of less than 90°.

acute arch, lancet arch A sharply pointed
arch whose centers are farther apart than the
width of the arch.

.ei

a^~ *\

acute arch

a.d. Abbr. for "air-dried."

AD l.Abbr. for "air-dried." 2. Abbr. for access
door. 3. Abbr. for area drain. 4. Abbr. for "as
drawn."

ADA Abbr. for Americans with Disabilities Act.

Adamesque style An inexact term implying a
derivation from the Adam style, but having pos-
sible differences depending on the time and
location of application.

Adam Revival See Colonial Revival.

addendum

Adam style fireplace

Adam style An architectural style based on the
work of Robert Adam (1728-1792) and his
brothers, predominant in England in the late
18th century and strongly influential in the US,
Russia, and elsewhere. It is characterized by clar-
ity of form, use of color, subtle detailing, and uni-
fied schemes of interior design. Basically
Neoclassical, it also adapted Neo-Gothic, Egypt-
ian, and Etruscan motifs.

adapt To make suitable for a particular purpose
or new requirements or conditions, by means of
modifications or changes.

adaptability The capacity of building spaces and
elements for being altered or being added to for
specific needs, as, for example, to accommodate
the needs of persons with and without disabilities.

adaptable According to the ADA, a restroom
or bathroom to which grab bars can be added or
which can be otherwise altered to accommodate
the needs of individuals with disabilities.

adaptable dwelling unit One of a number of
dwelling units that is on an accessible route and
equipped so it may be converted to be used, with
a minimum of structural change, by all cate-
gories of physically disabled persons.

adaptation The process by which the eye
changes sensitivity and becomes accustomed to
more or less light than it was exposed to during
an immediately preceding period.

adapter 1. A device for matching and properly
connecting items, tubing, or devices (especially
electric) which are of different size, operating
characteristics, or design. 2. A device that
enables different sizes or types of plugs, pipes,
etc., to be joined.

adapter

adaptive use, adaptive re-use The extensive
alteration, restoration, and/or renovation of an
existing building so that it will serve a new or
modified purpose. Also see building rehabilitation.

ADC Abbr. for "Air Diffusion Council."

ADD. l.On drawings, abbr. for addendum.
2. On drawings, abbr. for addition.

added lean-to Same as integral lean-to.

addendum A written or graphic instrument
issued prior to the execution of the contract
which modifies or interprets the bidding docu-
ments, including drawings, and specifications,
by additions, deletions, clarifications or cor-
rections; becomes part of the contract docu-
ments when the construction contract is
executed.

addition

addition l.A floor or floors, a room, wing, or
other expansion to an existing building. 2. In
building code usage: Any new construction which
increases the height or floor area of an existing
building or adds to it (as a porch or attached
garage). 3. An amount added to the contract sum
by a charge order; also see extra.

additional service authorization An AIA
form that authorizes additional work, 1 to be per-
formed, for an additional fee, for services not
covered in the originally specified scope of the
architect's work.

additional services The professional services
which may, upon the owner's request or approval,
be rendered by the architect in addition to the
basic services or the designated services.

additive A material, used in very small quan-
tity, to modify a specific property of another
material or otherwise improve its characteristics;
used in paints, plasters, mortars, etc.

additive alternate An alternate bid resulting
in an addition to the same bidder's base bid. Also
see alternate bid.

additus maximus In an ancient Roman
amphitheater, a main entrance.

addorsed, adorsed Said of animals or figures
placed back to back in decorative sculpture.

addorsed dolphins

addressable system A fire alarm system
whose integrity can be monitored and which
provides easy identification of the location of an
alarm condition; also provides for remote testing
and monitoring of the sensitivity of the detec-
tors from a control panel.

ADF In the lumber industry, abbr. for "after
deducting freight."

ADH On drawings, abbr. for adhesive.

adherend A body which is held to another by
an adhesive.

adhesion l.The joining of two surfaces as
pieces of wood, metal, plastic, or other construc-
tion materials, by means of a viscous, sticky
composition such as cement or glue. 2. The

sticking together of two surfaces by means of
physical and chemical forces such as those
which bind a paint film to a surface.

adhesion bond The adhesion of mortar or
grout to masonry units.

adhesion-type ceramic veneer Thin sec-
tions of ceramic veneer held in place by the
adhesion of mortar to unit and backing, requiring
no metal anchors; not more than YA in. (3.2 cm)
in overall thickness. Also see anchored-type
ceramic veneer.

adhesion-type filter A type of air niter in
which dirt particles are removed from air by
adhering to the filter as the air flows through it.

adhesive A substance capable of holding mate-
rials together by bonding the surfaces that are in
contact.

adhesive failure The separation of two sur-
faces joined by an adhesive, either by a force less
than that specified by the manufacturer or by
service conditions.

adiabatic Occurring without the gain or loss of
heat.

adiabatic curing The curing of concrete or
mortar in which adiabatic conditions are main-
tained during the curing period.

Adirondack Rustic style See Rustic style.

adit An entrance or passage.

adjoining grade elevation The average ele-
vation of the final grade adjoining all exterior
walls of a building, calculated from grade eleva-
tions taken at intervals (usually 10 ft or 3 m)
around the perimeter of the building.

adjustable base anchor A device used to
hold a doorframe above the finished floor.

adjustable base anchor

adjustable doorframe A doorframe which
has an adjustable jamb so that it can be installed
in walls of different thicknesses.

adobe

adjustable hanger A hanger having a provi-
sion for adjusting its length.

Hanger rod

adjustable hanger

adjustable multiple-point suspension scaf-
fold 1 . See mason's adjustable multiple-point
suspension scaffold. 2. See stone-setter's adjustable
multiple-point suspension scaffold.

adjustable proscenium On a theater stage,
an inner proscenium which is variable in height,
width, or position; may be hung from rigging
overhead or floor-mounted.

adjustable shelving Shelving supported by
metal clips or other movable supports, making it
possible to adjust the height of individual shelves.

adjustable shore, adjustable steel prop A
vertical shore used to support reinforced con-
crete beams and slab forms; usually all metal or a
combination of wood and metal; can be raised or
lowered within certain limits.

adjustable-speed motor An electric motor
in which the speed can be varied gradually over
a considerable range, but which, once adjusted,
remains virtually unaffected by the load, 3.

adjustable square, double square A try
square the arm of which is at right angles to the
handle; the position of the arm may be moved so
as to form an L or a T.

l*W[

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adjustable wrench Any one of several types
of wrenches having one jaw fixed and the other
adjustable; set to the desired size by means of a
knurled screw.

adjustable square

CRESCENT
adjustable wrenches

administration of the construction con-
tract See construction phase — administration
of the construction contract.

administrative authority The individual,
official, board, department, or agency estab-
lished and authorized by a city, county, state, or
political subdivision created by law to adminis-
ter and enforce the provisions of a code.

admixture A material other than water,
aggregates, lime, or cement, used as an ingredi-
ent of concrete or mortar, and added to the
batch immediately before or during its mixing;
used as a water repellent, as a coloring agent, as
a retarder or accelerator (to modify its setting
rate), etc.

adobe A heavy soil, composed largely of clay
and silt in sufficient quantities to form a matrix
in which sand particles are firmly imbedded;
water is added, and straw, manure, and fragments
of tile are sometimes combined with this mix-
ture to provide increased mechanical strength
and cohesion when it dries. It can be used as a
plaster or be formed into bricks, often shaped by
hand in a wooden form, then sun-dried; widely
used in Spanish Colonial architecture and its
derivatives. Adobe brick walls are often lime-
plastered to improve resistance to weather; a

adobe blasting

coating such as slaked lime acts

stabil

izmg

agent.
adobe blasting Same as mud-capping.
adobe brick Large, roughly molded, sundried

clay brick, usually of varying sizes.

adobe quemado An adobe brick that has
been kiln-dried at a temperature lower than that
required to produce a hard-burnt brick; usually
deep red in color, relatively soft, and rough in
texture.

adobero A box for mixing adobe and shaping it
into bricks.

adopted street In Britain, a dedicated street.

ADS Abbr. for "automatic door seal."

adsorbed water 1. Water which is held on the
surfaces of a material by electrochemical forces;
its physical properties are substantially different
from those of absorbed water or chemically com-
bined water at the same temperature and pres-
sure. 2. Water which is bound to soil particles as
a result of the attraction between electrical
charges on their surfaces and water molecules.

adsorbent A material (such as activated char-
coal) which has the ability to extract certain sub-
stances from gases, liquids, or solids by causing the
substances to adhere to its internal surface without
changing the adsorbent physically or chemically.

adsorption The action of a material in extract-
ing a substance from the atmosphere (or a mix-
ture of gases and liquids) and gathering it on the
surface in a condensed layer; the process is not
accompanied by physical or chemical change.

adulterine In the Middle Ages in Britain, said
of a castle that was crenelated without a license
to erect battlements. Such licenses were granted
by the reigning monarch in exchange for a cash
payment from the castle's owner.

advance slope grouting Grouting by a tech-
nique in which the front of the mass of grout is
forced to move horizontally through preplaced
aggregate.

advance slope method A method of con-
crete placement in which the face of the fresh
concrete moves forward as the concrete is placed;
the face of the fresh concrete is not vertical.

advanced nursery stock A deciduous tree,
of specified size, which has been transplanted
several times and has had its roots pruned in
preparation for its final transplantation.

adverse possession Occupation of property
by one not the true owner, openly, notoriously,
and continuously. See statute of limitations;
squatter's right; proscription.

advertisement curtain On the stage of a the-
ater, a curtain which bears advertisements; usu-
ally behind the asbestos curtain, but sometimes
(rarely) the asbestos itself.

advertisement for bids The published public
notice soliciting bids for a construction project.
Most frequently used to conform to legal re-
quirements pertaining to projects to be con-
structed under public authority, and usually
published in newspapers of general circulation
in those districts from which the public funds are
derived.

adytum, adyton 1. The inner shrine of a tem-
ple reserved for the priests. 2. The most sacred
part of a place of worship.

adytum: plan of a Roman temple, showing the adytum at A

adz A cutting tool whose thin arching blade is
perpendicular to the handle; used for the rough-
shaping of wood.

adz

adze British term for adz.

A/E Abbr. for architect-engineer.

AEA Abbr. for "Aluminum Extruders Associ-
ation."

A/F

aedes 1 . In Roman antiquity, any edifice or a
minor shrine, not formally consecrated. 2. Now,
any chapel or temple.

aedicula 1 . A canopied niche flanked by colon-
nettes intended as a shelter for a statue or as a
shrine. 2. A door or window framed by columns
or pilasters and crowned with a pediment. 3.
Diminutive of aedes. 4. A small chapel.

aedicula, 1

aegicranes Sculptured representations of the
heads or skulls of goats or of rams; used as deco-
rations on ancient altars, friezes, etc.

.?*»«*i

SWB

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aegicranes

aerarium In ancient Rome, the public
treasury.

aerate To introduce air into soil or water by nat-
ural or artificial means.

aerated concrete See cellular concrete.

aerated plastic Same as foamed plastic.

aeration 1. Exposing a substance to circulat-
ing air. 2. In landscape architecture, the addi-
tion of air into the soil; may be implemented
by a plow-like mechanism or by the addition of
an air-entrained material, such as vermiculite
or peat moss, during the soil-conditioning
process.

aerator fitting A device which introduces air
into an exiting stream of water.

aerial cable An overhead electric cable (field-
assembled at a construction site) which is
attached to poles or other supporting structures.

aerial photograph, aerophoto A photo-
graph taken from a vehicle in flight.

aerial photomap An aerial photograph or
photomosaic to which is added basic mapping
information such as place names, boundaries,
etc.

aerial photomosaic A composite of aerial
photographs depicting a portion of the earth's
surface.

aerodynamic noise Noise resulting from
the flow of air; often generated in an air-
conditioning system when an airstream encoun-
ters protuberances, rough surfaces, and/or blunt
edges.

aerofilter A bed of coarse material used for the
rapid filtering of sewage; recirculation of the
effluent may be employed.

aerograph A spray gun for paint.

aerophoto An aerial photograph.

aerosol paints Paints which are packaged in a
pressurized container for spray application.
Pressure is supplied by compressed liquefied
gas.

aes In ancient Rome or Greece: copper, tin, or
any alloy of these metals.

aetoma, aetos A pediment, or the tympanum
of a pediment.

A/F In a portland cement mixture, the abbr. for
"molar or weight ratio of aluminum oxide to iron
oxide."

affronted

affronted, affronte Said of animals or figures
facing each other, as in pediments, overdoors, etc.

affronted

AFNOR Abbr. for "Association Francaise de
Normalisation."

A-frame A three-piece rigid structural frame in
the shape of the upright capital letter A.

A»frame house A house, usually constructed
of wood, with a roof that extends steeply down-
ward from both sides of a central ridge, almost to
the building foundation; the roof is supported by
a rigid structural framework in the shape of the
capital letter A. One or both end walls of the
house are often almost completely glazed. Much
of the living area on the ground floor is open to
the underside of the roof; the bedrooms are fre-
quently located on a balcony directly under the
roof; often, there is an exterior deck at one end
or both ends of the house. Also see rafter house.

A-frame house

African cherry See makore.
African ebony See ebony.
African mahogany Same as khaya.
African rosewood See bubinga.

after cooler A device that cools compressed air
after it is fully compressed.

afterfilter, final filter In an air-conditioning
system, a high-efficiency filter located near a ter-
minal unit.

afterflaming The continued flaming combus-
tion of a material after the exposing flame has
been removed.

after»flush The residue of water in a toilet flush
tank after it has been flushed; after flushing, the
residue gradually drains from the flush tank to
seal the trap.

afterglow The glow in a material after the
removal of an external source of fire to which it
is exposed, or after the cessation (natural or
induced) of flames.

aftertack, residual tack The lingering tack
or stickiness of a paint film which remains over a
long period of time.

AG l.Abbr. for "above grade." 2. Abbr. for
"against the grain."

AGA Abbr. for "American Gas Association."

agalma In ancient Greece, any work of art ded-
icated to a god.

agba A large central African tree with rather
lightweight wood of a creamy to pinkish brown
color. Used for plywood, interior millwork, and
carpentry.

AGC Abbr. for "Associated General Contractors."

age hardening An aging process in certain
metals, at room temperature, which results in
increased strength and hardness.

ageing British variant of aging.

agency l.A relationship by which one party,
usually the agent, is empowered to enter into
binding transactions affecting the legal rights of
another party, usually called the principal, as, for
example, entering into a contract or buying or
selling property in his name or on his behalf.
2. An administrative branch of government
(federal, state, or local).

agent One who is empowered to enter into
binding transactions on behalf of another (usu-
ally called the principal).

age softening The loss of strength and hard-
ness at room temperature which takes place in
certain alloys owing to spontaneous reduction of
residual stresses in the strainhardened structure.

agnus dei

agger l.In ancient Rome, an earthwork; an
artificial mound or rampart. 2. The fill for a road
over low ground.

agglomerate stone See artificial stone.

agglomeration The collecting together of tiny
suspended particles into a mass of larger size, one
which will settle more rapidly.

AGGR On drawings, abbr. for aggregate.

aggradation The addition of a material to the
earth's surface to promote the uniformity of a
grade or slope.

aggregate 1. An inert granular material such as
natural sand, manufactured sand, gravel, crushed
gravel, crushed stone, vermiculite, perlite, and
air-cooled blast-furnace slag, which when bound
together into a conglomerate mass by a matrix
forms concrete or mortar. 2. An inert granular
material that may be added to gypsum plaster.

aggregate bin A structure designed for storing
and dispensing dry granular construction materi-
als such as sand, crushed stone, and gravel; usu-
ally has a hopper-like bottom that funnels the
material to a gate under the structure.

aggregate blending The mixing of two or
more aggregates so as to obtain different aggre-
gate properties.

aggregate interlock The projection of aggre-
gate particles or portions thereof from one side of
a joint or crack in concrete into recesses in the
other side so as to effect load transfer in compres-
sion and shear, and maintain mutual alignment.

aggregate strength The strength of a wire
rope determined by summing the individual
breaking strength of the strands of which it is
fabricated.

agiasterium In the early church, that part of a
basilica in which the altar was set up.

aging, Brit, ageing l.The progressive change
in a chemical and physical material with
increased age; in natural rubber and synthetic
elastomers, usually marked by a deterioration
caused by oxidation. Also see accelerated aging,
age hardening, age softening. 2. The storing of
varnish to improve clarity and gloss.

agitating lorry British term for agitating truck.

agitating speed The rate of rotation of the
drum or blades of a truck mixer or other device
used for agitation of mixed concrete.

agitating truck, Brit, agitating lorry A

vehicle carrying a drum in which freshly mixed
concrete can be conveyed from the point of mix-
ing to that of placing, the drum being rotated
continuously so as to agitate the contents.

agitation l.The process of providing gentle
motion in mixed concrete, just sufficient to pre-
vent segregation or loss of plasticity. 2. The mix-
ing and homogenization of slurries or finely
ground powders by air or mechanical means.

agitator 1 . A mechanical device used to mix a
liquid contained in a vessel. 2. A device for
maintaining plasticity and preventing segrega-
tion of mixed concrete by agitation.

agitator body A truck-mounted drum for trans-
porting freshly mixed concrete; rotating internal
paddles or rotation of the drum prevents the set-
ting of the mixture prior to its delivery at the site.

agitator body

AGL Abbr. for "above ground level."
agnus dei Any image or representation of a
lamb as emblematic of Christ, esp. such a

agnus dei

agora

representation with a halo and supporting the
banner of the cross.
agora The chief meeting place or marketplace
in an ancient Greek city.

agora: plan of the agora of Antiphellus

agrafe, agraffe The voussoir or keystone of an
arch, especially when carved as a cartouche.

agrafe

agreement 1. A meeting of minds. 2. A legally
enforceable promise or promises between two or
among several persons. 3. On a construction proj-
ect, the document stating the essential terms of
the construction contract which incorporates by
reference the other contract documents. 4. The
document setting forth the terms of the contract
between the architect and owner or between the
architect and a consultant. 5. An arrangement
indicating the intent of a contract but not neces-
sarily fulfilling all the enforceable provisions of it.
Also see agreement form, contract.

agreement form A document setting forth in
printed form the general provisions of an agree-
ment with spaces provided for insertion of spe-
cific data relating to a particular project.

Agrement Board See British Board of Agre-

ment.
agricultural drain Same as agricultural pipe

drain.

agricultural lime A hydrated lime which is
used to condition soil.

agricultural pipe drain A system of porous or
perforated pipes laid in a trench filled with
gravel (or the like); used for draining subsoil.

aguilla An obelisk, or the spire of a church
tower.

Ah Abbr. for "ampere-hour."

aha Same as ha-ha.

AHU Abbr. for air-handling unit.

AIA Abbr. for "American Institute of Archi-
tects."

AIA uniform system See contract documents
and uniform system.

AIEE Abbr. for "American Institute of Electrical
Engineers."

aiguille A slender form of drill used for boring
or drilling a blasthole in rock.

aileron A half gable, such as that which closes the
end of a penthouse roof or of the aisle of a church.

AIMA Abbr. for "Acoustical and Insulating
Materials Association."

aiming angle Same as angle of illumination;
usually measured in degrees.

air balancing A procedure used to adjust the
flow of air in an HVAC system so as to meet the
design goals for airflow throughout the system.

air barrier A membrane that acts as a resis-
tance to air leakage.

air-blown mortar Same as shotcrete.

air blowpipe A pipe which emits a jet of air;
used to clean an area of debris.

airborne sound Sound that reaches a point
in a building by propagation from the source
through air.

air»bound Said of a pipe or apparatus in which
the presence of a pocket of air prevents or
reduces the desired liquid flow in the pipe or
apparatus. Also see air lock, 2.

air content

air break In a drainage system, a piping
arrangement in which a drain from an appli-
ance, device, or fixture discharges into the open
air and then into another fixture, receptacle, or
interceptor; used to prevent back siphonage or
backflow.

air brick A perforated brick or perforated metal
unit of brick size which is built into a wall; used
for ventilation.

airbrush A small tool used for the fine-spray
application of paint, dye, watercolor pigment, or
ink by compressed air.

. CtnjOfi CUP .-■ MNGCS LtVEH

airbrush

air chamber In a water piping system near a
valve or faucet, a vertical pipe stub which is
sealed at the top and contains air; the entrapped
air provides a cushion when the valve is closed
suddenly, thereby eliminating the noise of water
hammer.

air changes A measure of the volume of air
supplied to or exhausted from a building (or
room); usually expressed in terms of the number
of complete changes of air per hour in the room
or space under consideration.

air circuit breaker A type of circuit breaker
utilized in commercial buildings at medium
voltage; the word "air" refers to the insulating
medium between contacts in the circuit breaker.

air circulation Natural or imparted motion of
air.

air cleaner A device (such as an air washer, air
filter, electrostatic precipitator, or charcoal fil-
ter) which removes airborne impurities such as
dust, smoke, or fumes.

air cock Same as pet cock.

air compressor A machine which draws in air
at atmospheric pressure, then compresses it to
pressures higher than atmospheric and delivers
it at a rate sufficient to operate pneumatic tools
or equipment.

air compressor

On drawings, abbr. for "air con-
A device for providing air

AIR COND

dition."
air conditioner

conditioning.

air conditioning 1 . The process of treating air
so as to control simultaneously its temperature,
humidity, cleanliness, and distribution within an
interior space such as a room or building. 2.
Same as definition 1, but also controlling odor
and noise.

air-conditioning duct See air duct.

air-conditioning grille Same as inserted
grille.

air-conditioning lock A type of window lock
requiring a special key or wrench to open it; used
where the window is to be opened only for spe-
cial purposes, such as cleaning.

air-conditioning lock

air-conditioning system An assembly of
components for the treatment of air, controlling
its temperature, humidity, cleanliness, and dis-
tribution within an air-conditioned space. Types
of systems differ, but the basic components may
include: outside-air intake, preheater, return-
air intake, filters, dehumidifier, heating coil,
humidifier, fans, ductwork, air outlets, air termi-
nals, refrigeration machine, piping, pumps, and
water or brine. See heating, ventilating, and air-
conditioning system.

air-conditioning unit Same as room air
conditioner.

air content The volume of air voids in cement
paste, mortar, or concrete, exclusive of pore

air control valve

space in aggregate particles, usually expressed as
a percentage of total volume of the mixture.

air control valve Same as air maintenance
device.

air-cooled blast-furnace slag The material
resulting from solidification of molten blast-
furnace slag under atmospheric conditions. Also
see blast-furnace slag.

air-cure To vulcanize at ordinary room temper-
atures, or without the aid of heat.

air cushion tank Same as expansion tank.

air curtain A stream of high- velocity tempera-
ture-controlled air which is directed downward,
across an opening; excludes insects, exterior
drafts, etc.; prevents the transfer of heat across
it, and makes it possible to air-condition a space
having an open entrance; used in exterior doors,
on loading platforms, etc.

MOUNTING ON OUTSIK
Of EXKJHORKUL^

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air curtain or air door

air damper See damper, 1.

air diffuser An air distribution outlet, usually
located in the ceiling and consisting of deflect-
ing vanes discharging supply air in various direc-
tions and planes, and arranged to promote

air diffuser

mixing of the air which is supplied to the room
with the air already in the room.

air-distributing acoustical ceiling A sus-
pended acoustical ceiling in which the board, per-
forated metal, or tile is provided with small, evenly
distributed mechanical perforations through the
material; designed to provide a desired flow of air
from a pressurized plenum above.

air door Same as air curtain.

air drain An empty space left around the ex-
ternal foundation wall of a building to prevent
the earth from lying against it and causing
dampness.

air-dried lumber, natural-seasoned lum-
ber Wood dried by exposure to air under nat-
ural conditions; usually has a moisture content
not greater than 24%.

air drill Same as pneumatic drill.

air-dry moisture content The moisture con-
tent of a piece of wood after it has been exposed
to its environment long enough to attain
moisture-content equilibrium without the appli-
cation of heat.

air drying The process of drying slowly under
ambient conditions of temperature and humid-
ity, as in the natural seasoning of lumber or the
hardening of paint.

air duct A duct, usually fabricated of metal,
fiberglass, or concrete; used to transfer air from
one location to another.

air eliminator In a piping system, a device
used to remove air from water, steam, or a refrig-
erant.

air-entrained concrete Concrete made with

air-entraining cement or an air-entraining
agent. Same as cellular concrete.

air entraining Descriptive of the capability of
a material or process to develop a system of
minute bubbles of air in cement paste, concrete,
or mortar.

air-entraining admixture An admixture that
causes the development of air bubbles in con-
crete or mortar during its mixture.

air-entraining agent An addition for hydraulic
cement or an admixture for concrete or mortar
which causes air to be incorporated in the form of
minute bubbles in the concrete or mortar during
mixing, usually to increase its workability and
frost resistance.

air leakage

air-entraining hydraulic cement Hydrau-
lic cement which contains an air-entraining
agent in an amount such as to cause air to be
entrained in the mortar, within specified limits.

air entrainment The occlusion of air in the
form of tiny bubbles (generally smaller than 1 mm)
during the mixing of concrete or mortar; used to
improve its workability.

air exfiltration See exfiltration, 1.

air-exhaust ventilator 1 . An air-exhaust unit
used to carry away odors and fumes from a stove,
griddle, etc.; may contain a grease-extracting
device or an air filter; sometimes includes a fire-
extinguishing device. 2. Any air-exhaust unit
used to carry away dirt particles, odors, or fumes
(as in an industrial plant); the ventilator may be
mechanically actuated or of the gravity type.

air filter Any device used to remove solid
and/or gaseous pollutants from air.

air filtration The use of an air filter to provide
clean air.

airflow vane Same as turning vane.

air flue See flue.

airfoil vane Same as turning vane.

air- fuel ratio The ratio of the volume (or
weight) of air being furnished for combustion to
the volume (or weight) of the fuel.

air gap l.The unobstructed vertical distance
between the lowest opening of a faucet (or the
like) which supplies a plumbing fixture (such as
tank or wash bowl) and the level at which the
fixture will overflow. 2. In a drainage system, the
unobstructed vertical distance between the out-
let of a waste pipe and the flood-level rim of the
receptacle into which it discharges. 3. A gap in
an electric or magnetic circuit; usually acts as a
high-resistance path in the circuit.

''(■I^Ulf ^:i*»ltf Lne

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air gap, 1

air gap, 2

air grating 1. A fixed metal grille on the exte-
rior of a building through which air is brought
into, or discharged from, the building for pur-
poses of ventilation. 2. An air diffuser.

air grille A type of air grating.

air gun l.Same as spray gun. 2. See shotcrete
gun.

air hammer, pneumatic hammer A por-
table tool, driven percussively by air pressure,
into which is set a chisel, hammer, or the like.

air-handling luminaire Same as air-light
troffer.

air-handling system An air-conditioning sys-
tem in which an air-handling unit provides part
of the treatment of the air.

air-handling unit; packaged fan equip-
ment An assembly of air-conditioning com-
ponents (such as fans, cooling coils, filters,
humidifiers, and dampers) integrated into a self-
contained package and often installed as a single
unit, which is connected to system of metal
ductwork that distributes the conditioned air.

air heating system See warm-air heating
system.

air hole In the foundation of a house, an
opening that provides ventilation for a crawl
space.

air house Same as pneumatic structure.

air-inflated structure Same as pneumatic
structure.

air inlet In an air-conditioning system, a device
through which air is supplied to the system.

air intake Same as outside-air intake.

air lance A rod-shaped device for directing a
high-velocity stream of compressed air; used to
clean away debris from a surface.

air leakage l.The volume of air which flows
through a closed window or door in a given length

airless spraying

of time as a result of the difference in air pressure
on its opposite faces. 2. In ductwork, air which
escapes from a joint, coupling, etc. 3. The unde-
sired leakage or uncontrolled passage of air from a
ventilation system. 4. The flow of uncontrolled air
through cracks or openings in an enclosure within
a building (such as a HVAC plenum) or through
the surfaces which enclose the building.

airless spraying, hydraulic spraying The
spraying of paint by means of high fluid pressure
and special equipment.

air lift 1. Equipment for lifting slurry or dry
powder through pipes by means of compressed
air. 2. The use of compressed air, introduced in
water at the bottom of an open-ended cased pile
or cell of a cofferdam, to rid it of loose material.

air»lift pump A type of pump for raising water
from a well, consisting of a pipe which surrounds
another of smaller diameter; compressed air is
injected into the smaller pipe, causing water to
rise up the larger pipe.

toucropfTf*

air-lift pump

air»light troffer In an air-conditioning system,
a unit which combines the functions of a light
fixture and an air terminal unit.

air line A duct, hose, or pipe that supplies
compressed air to a pneumatic tool or piece of
equipment.

air lock 1. A space which is designed to isolate
an air conditioned space from another space to
which it is connected. 2. In a pump or piping sys-
tem, the stoppage of flow resulting from the pres-
ence of trapped air. 3. An enclosure with control
doors between two rooms that permits the ingress

and egress from one room to another while per-
mitting minimal air movement between rooms.
air»lock strip The weather stripping which is fas-
tened to the edges of each wing of a revolving door.

air maintenance device A valve required to
introduce air into a tank which stores water
under pressure.

air meter A device for measuring the air con-
tent of concrete and mortar.

air-mixing plenum In an air-conditioning
system, an enclosed volume in which recircu-
lated air is mixed with fresh air for distribution
throughout the system.

air monitoring During the removal of asbestos
in buildings, the measurement of asbestos fiber
content in the air.

air motor An air-operated device used to open
or close a damper, 1 or valve.

air moving device See fan.

air outlet In an air-conditioning system, a
device at the end of a duct through which air is
exhausted.

air permeability test A test for the measure-
ment of the fineness of powdered materials, such
as portland cement.

air pipe A seldom-used synonym for vent pipe.

airplane bungalow A Craftsman style bunga-
low having a gable whose face is parallel to the
main ridge of the roof; its second floor is a single
room.

air pocket An air-filled volume within a sec-
tion of piping (or an apparatus) which is nor-
mally filled with liquid.

air pressure-reducing valve See pressure-
reducing valve.

air pressure relief vent A relief vent.

air pump A pump used to exhaust or to com-
press air, or force it through another apparatus.
Also see air compressor.

air purge valve A device which eliminates
trapped air from a piping system.

air quality See indoor air quality.

air receiver On an air compressor, the air stor-
age tank.

air register Same as register.

air regulator A device for regulating airflow, as
in the burner of a furnace.

air vessel

air reheater In a heating system, any device used
to add heat to the air circulating in the system.

air release valve A valve, usually manually
operated, which is used to release air from a
water pipe or fitting.

air right The legal property right for use of the

space above a specified elevated plane; usually
includes the right to ground support but excludes
other rights to ground use, e.g., the right to con-
struct a building over a railroad track.
air»ring In the placement of shotcrete, a perfo-
rated manifold through which air is introduced
into the flow of material.

air scrubber See air washer.
air-seasoned lumber See air-dried lumber.

air separator An apparatus for separating
ground-up materials pneumatically into various
sizes.

air»set To allow material to harden under nor-
mal atmospheric pressure and temperature.

air shaft, air well A ventilating shaft; a roof-
less enclosed area within a building or between
buildings; may have openings such as windows.

air shutter A device for regulating the quantity
of air being mixed with gas for combustion.

air-slaked Said of a surface that is wetted by the
exposure to moisture in air.

air slaking Absorption by quicklime or cement
of moisture and carbon dioxide from the atmo-
sphere, causing the material to change its chem-
ical composition.

air space The space above private property or
public property for which air rights may be

granted.

air-supported structure See pneumatic
structure.

air tap Same as air vent.

air terminal In a lightning protection system,
the combination of a metal rod and its brace or
footing, on the upper part of a structure.

air terminal unit In air-conditioning, same as
terminal unit.

air test A test that applies uniform air pressure
throughout a drainage system being tested for
leakage. This test is recommended in lieu of a
water test when there is a danger of water freez-
ing during the test.

AUTHMINAL

CONDUCTOi

air terminal

air test, pneumatic test A test for leaks in
drainage systems, in soil, waste, and ventilating
pipe systems, or in ductwork; all openings are
sealed, and compressed air is introduced into the
system; air leakage is indicated by means of a U-
gauge or other suitable pressure gauge.

air tight Said of an enclosure or barrier that
does not permit the passage of air.

air-to-air resistance The resistance pro-
vided by the wall of a building to the flow of
heat. See thermal conductance and thermal
resistance.

air-to-air transmission coefficient See
thermal transmittance.

air trap Same as trap, 1.

air valve A valve used to admit or discharge air
from a pipeline.

air vent In a water distribution system, a vent
for releasing trapped air; usually located at the
highest point in the system.

air ventilation The quantity of air which must
be supplied to maintain the desired quality of air
within a space.

air vessel 1. An enclosed volume of air which
uses the compressibility of air to minimize water
hammer. 2. An enclosed chamber using the

air void

compressibility of air to promote a more uniform
flow of water in a piping system.

air void A space which is filled with air in
cement paste, mortar, or concrete. Also see
entrapped air, entrained air.

air washer A water spray system or device for
cleaning, humidifying, or dehumidifying the air.

air»water jet l.A jet of air and water mixed,
which leaves a nozzle at high velocity; used
in cleaning the surfaces of concrete or rock. 2. In
cleaning concrete or rock surfaces, a high-velocity
jet consisting of a mixture of air and water.

air-water storage tank A water storage tank
in which the air, above the water, is compressed.

airway A passage for ventilation between ther-
mal insulation and roof boards.

airway

air well See air shaft.

AISC Abbr. for "American Institute of Steel
Construction."

AISI Abbr. for "American Iron and Steel
Institute."

aisle l.A longitudinal passage between sections
of seats in an auditorium or church. 2. In a
church, the space flanking and parallel to the
nave; usually separated from it by columns,
intended primarily for circulation but sometimes
containing seats.

aisle access way A continuous, unobstructed
accessible route around seating, furniture, or
desks so as to provide adequate clearance for the
disabled.

aisleway A passage or walkway within a fac-
tory, storage building, or shop permitting the
flow of inside traffic. Also see aisle.

AITC Abbr. for "American Institute of Timber
Construction."

aiwan A reception hall in an ancient Parthian

building.

ajaraca In southern Spain, an ornament in

brick walls, formed of patterns, a half brick deep,

more or less complicated.
a jour, ajoure Pierced, perforated, or cut out to

form a decorative opening in wood, stone,

metal, or other material.
AL On drawings, abbr. for aluminum.

ala 1 . An alcove or small room opening off the
atrium of an ancient Roman house. 2. A small
room on each side of a cella.

alabaster Fine-grained, translucent variety of very
pure gypsum, generally white or delicately shaded.

A-labeled door A door carrying a certification
from the Underwriters' Laboratories, Inc. that it
meets the requirements for a class-A door.

alameda A shaded public walk or promenade.

alarm system An electrical system that is
installed in a building as a protective measure
against fire or unauthorized entry. In the event
that the system is activated, an alarm (such as an
audible signal or flashing light) is turned on; see
fire alarm system and burglar alarm system.

alarm valve See wet alarm valve.

alatorium l.A piazza, corridor, or covered
walk. 2. The flank of a building.

albani stone A pepper-colored stone used in
buildings in ancient Rome before the introduc-
tion of marble.

albarium A white lime used for stucco; made
by burning marble.

albronze Same as aluminum bronze.

album In ancient Roman architecture, a space
on the surface of a wall covered with white plas-
ter, located in a public place, on which public
announcements and records, etc. were written.

alburnum Same as sapwood.

alcazar A Moorish or Spanish fortress or castle.

alclad A metal product clad with an aluminum
or aluminum-alloy coating, usually as a protec-
tion against corrosion.

alcove A small recessed space, opening directly
into a larger room.

alder A moderately light-colored, light-weight
hardwood that changes to flesh color or light
brown when dried; often stained to simulate
cherry, mahogany or walnut; often used as ply-
wood core and crossbanding.

aligning punch

aleatorium In ancient Roman architecture, a
room in which dice games were played.

ale house In an early British or American com-
munity: a village tavern licensed to sell alco-
holic beverages.

alette 1. A minor wing of a building. 2. A door
jamb. 3. A rear pilaster, partially visible within
a cluster of columnar elements. 4. The wing of
the pier on both sides of an engaged column.

j gggl

alettes, 4 C

Alexandrian work Same as opus Alexan-
drinum.

Alexandrinum opus Same as opus Alexan-
drinum.

alfiz A decorative molding enclosing a door or
arch.

alfiz

Alhambra A fortress and palace built by the
Moorish kings of Granada in southern Spain,
completed in the 14th century.

Alhambresque Ornamentation that resem-
bles the fanciful style used at the Alhambra.

alicatado Tile work which is executed with
azulejos; used to decorate pavements and walls,
especially in patios.

alhambresque

alidade The part of a surveying instrument
which consists of a sighting device, with index,
and reading or recording accessories.

alienation The transfer of title to real property
by one person to another.

aliform Having a wing-like shape or extensions.

aligning punch A punch used for lining up mat-
ing holes prior to riveting or bolting; a drift punch.

aligning punch

alignment

alignment 1. An adjustment in a straight line. 2.
The theoretical, definitive lines that establish the
position of construction (such as a building) or the
shape of an individual element (such as a curved or
straight beam). 3. In highway and other surveys,
the ground plan depicting direction of the route as
distinguished from a profile, which shows the ver-
tical element. 4. In prehistoric building, formal
alleys of standing stones, as at Carnac in France.

alipterion In ancient Roman architecture, a
room used by bathers for anointing themselves.

alite A principal constituent of portland-
cement clinker; primarily tricalcium silicate, but
includes small amounts of magnesium oxide,
aluminum oxide, ferric oxide, and other oxides.

alive Same as live, 1 .

alkali Any of the various chemically active
bases such as the soluble salts of metals, e.g., the
water-soluble salts of sodium and potassium
which occur in constituents of concrete and
mortar that may result in deleterious expansion.

alkali-aggregate reaction A chemical reac-
tion in mortar or concrete between alkalies from
Portland cement or other sources and certain
constituents of some aggregates; under certain
conditions, deleterious expansion of the con-
crete or mortar may result.

alkalinity See pH.

alkaline soil Soil containing soluble salts of
magnesium, sodium, or the like, and having a
pH value of between 7.3 and 8.5.

alkali reactivity Of a concrete aggregate, its
susceptibility to alkali-aggregate reaction.

alkali resistance l.The degree to which a
paint resists reaction with alkaline materials such
as lime, cement, plaster, soap, etc.; a necessary
property for paints in bathrooms, kitchens, laun-
dries. 2. The degree to which a porcelain enamel
will resist attack by aqueous alkaline solutions.

alkali-silica reaction In portland cement, the
reaction between the alkalies and particular
siliceous rocks and/or minerals which are
present in some aggregates; may result in abnor-
mal expansion and cracking of concrete under
service conditions.

alkali soil A soil, with salts injurious to plant
life, having a pH value of 8.5 or higher.

alkyd paint A paint using an alkyd resin as the
vehicle for the pigment.

alkyd resin One of a group of thermoplastic
synthetic resins; used in bonding materials, in
adhesives, and in paints and varnishes.

allee A broad walk, planted with trees on either
side, usually at least twice as high as the width of
the walk.

allege A part of a wall which is thinner than the
rest, esp. the spandrel under a window.

allege

allegory A figurative representation in which
the meaning is conveyed symbolically.

allegory: Cathedral of Worms, 13th cent. The beast with
four heads symbolizes the Four Gospels

Allen head A screw having a hexagonally

shaped recess in its head.
Allen wrench A wrench for Allen head

screws; a steel bar, hexagonal in shape, which is

bent to form a right angle.

Allen wrench

almena

alley 1 . A service way providing a secondary
public means of access to abutting properties; a
narrow passageway between or behind buildings,
sometimes permitting traffic for only one lane of
cars. 2. A garden walk between rows of trees; an
allee.

all-heart lumber Lumber that is all heart-
wood, entirely free of sapwood.

alligator hide A surface condition on porce-
lain enamel, characterized by an extreme rough-
ness; a severe case of orange peel.

alligatoring 1. The splitting of a film of paint
in a pattern resembling an alligator skin, caused
by shrinkage of a coat of paint applied over a
semiplastic or thermoplastic undercoat; also
called crocodiling. 2. Surface cracking, due to
oxidation and shrinkage stresses, which shows
as repetitive mounding of an asphalt surface in a
pattern resembling the hide of an alligator;
occurs only in unsurfaced bitumen exposed to
the weather.

alligator shears, lever shears Wide-jawed
shears, resembling the jaws of an alligator,
used to cut sheets of metal; operated by a foot
lever.

alligator wrench A wrench having V-shaped,
fixed serrated jaws; used to turn cylindrical parts,
esp. in fitting pipe.

all-in aggregate See bank-run gravel.

all-in contract Same as turn-key job.

allotment garden Any privately or publicly
owned garden area which has been divided
into plots for assignment to individuals for
their use.

allover A pattern covering an entire surface;
usually one which is repeated.

ALLOW. On drawings, abbr. for "allowance."

allowable bearing value, allowable soil
pressure, allowable bearing capacity
The maximum permissible pressure on founda-
tion soil that provides adequate safety against
rupture of the soil mass or movement of the
foundation of such magnitude as to impair the
structure that imposes the pressure.

allowable load The load which induces the
maximum permissible unit stress at a critical sec-
tion of a structural member.

allowable pile bearing load The maximum
permissible load on a pile that provides adequate

safety against movement of such magnitude that
would endanger the structure supported by the
pile.

allowable pile load The allowable concentri-
cally applied load which is permitted along the
central axis of a pile.

allowable soil pressure See allowable bear-
ing value.

allowable stress In the design of structures,
the maximum unit stress permitted under work-
ing loads by codes and specifications.

allowance l.See cash allowance. 2. See con-
tingency allowance.

alloy A composition of two or more metals
fused together, usually to obtain a desired
property.

alloy steel Steel containing one or more alloying
elements other than carbon, such as chromium,
molybdenum, or nickel, which have been added
(in an amount exceeding a specified minimum)
to impart particular physical, mechanical, or
chemical properties.

all-risk insurance On a construction project,
insurance that protects the policyholder against
all risks other than those which are specifically
excluded by the policy.

all-rowlock wall See rowlock cavity wall.

all-stretcher bond A masonry bond, 6 show-
ing only stretchers on the face of the brick wall;
same as stretcher bond.

allure See alure.

alluvial deposit Earth, sand, gravel, or other
rock or mineral materials transported and laid
down by flowing water.

alluvium Gravel, sand, silt, soil, or other mate-
rial that is deposited by running water.

ALM On drawings, abbr. for "alarm."

almariol A storage place for ecclesiastical vest-
ments; an ambry.

almary See ambry.

almehrabh In Arabian architecture, a niche
in a mosque which marks the direction of
Mecca.

almemar, almemor l.A bema, 2. 2. In a
synagogue, a desk on which the Torah is placed
while being read to the congregation.

almena An indented trapezium serving as an
embattled parapet. (See illustration p. 28.)

almery

almery See ambry.
almocarabe Same as ajaraca.

almond An aureole of elliptical form.
almonry A building or part thereof where alms

are distributed.
almorie Same as almariol.
almorrefa In Hispanic architecture, brickwork

intermixed with azulejos; used as flooring.
almshouse 1 . A building in which charity was

distributed to the poor; found in England and in

some early American settlements and cities; also

see poorhouse. 2. An almonry.
alpha brass An alloy containing 51 to 61%

copper and 39 to 45% zinc; used in hot- water

systems because of its corrosion resistant pro-

perties.
alpha gypsum A specially processed gypsum

having low consistency and high compressive

strength, often exceeding 5,000 lb per sq in.

(352 kg per sq cm).
ALS Abbr. for "American Lumber Standards."
ALT On drawings, abbr. for "alternate."
altana A light ornamental structure on a roof

that serves much the same function as a gazebo.
altar l.An elevated table, slab, or structure,

often of stone, rectangular or round, for religious

rites, sacrifices, or offerings. 2. The Communion

table in certain churches.
altar frontal An ornamental hanging or panel

for the front of an altar.
altar of repose In a Roman Catholic church, a

side altar, repository, or storage niche where the

Host is kept from Maundy Thursday to Good

Friday.

altarpiece A decorative screen, painting, or
sculpture above the back of an altar.

altar rail A low rail or barrier in front of the
altar, running transversely to the main axis of
the church and separating the officiating clergy
from the other worshipers.

altar screen A richly decorated partition of
stone, wood, or metal, separating the altar from
the space behind it.

altar slab, altar stone A flat stone or slab
forming the top of an altar.

altar tomb A raised tomb, or monument cover-
ing a tomb, whose shape resembles an altar.

alteration Construction in a building which
may change the structural parts, mechanical
equipment, or location of openings, but does not
increase the overall area of dimensions of the
building.

alterations l.A construction project (or por-
tion of a project) comprising revisions within or
to prescribed elements of an existing structure,
as distinct from additions to an existing struc-
ture. 2. Remodeling.

alternate A change in work, 1 described in the
contract documents for a building that gives the
owner the option of selecting various products,
materials, or systems, and/or the right to add or
delete portions of the work, 1.

alternate bid The amount stated in the bid to
be added to or deducted from the amount of the
base bid if the corresponding change in project
scope or alternate materials and/or methods of
construction is accepted.

alternating current An electric current that
varies periodically in value and direction, first

alure

flowing in one direction in the circuit and then
flowing in the opposite direction; each com-
plete repetition is called a cycle, and the num-
ber of repetitions per second is called the
frequency; usually expressed in Hertz (Hz).

alternating Flemish bond A brickwork pat-
tern which is produced by laying alternate
courses of Flemish bond and common bond.

alternating sprinkler system A fire sprin-
kler system that can be changed from a wet-pipe
sprinkler system in the summer to a dry-pipe
sprinkler system in the winter.

alternator A generator of alternating current
which is produced by the turning of its rotor.

ALTN On drawings, abbr. for "alteration."

alto-rilievo, alto-relievo See high relief.

alum A chemical compound added to gypsum
plaster to make the plaster harden faster.

ALUM. On drawings, abbr. for aluminum.

alumina The oxide of aluminum; an important
constituent of the clays used in brick, tile, and
refractories.

aluminium British term for aluminum.

aluminize, Brit, aluminise To apply a surface
coating of aluminum to another metal or other
base material, usually by spraying or dipping in
molten aluminum. On steel, such coatings
greatly increase corrosion resistance.

aluminous cement See calcium aluminate
cement.

aluminum, Brit, aluminium A lustrous,
silver-white, nonmagnetic, lightweight metal
which is very malleable; has good thermal and
electrical conductivity; a good reflector of both
heat and light. In construction, most aluminum
is used in alloy form because of added strength;
further strengthened by heat treatment; used in
extrusions, castings, and sheets. Excellent resis-
tance to oxidation; often anodized for better
corrosion resistance, surface hardness, and/or
architectural color requirements.

aluminum brass Brass to which aluminum
has been added to increase its corrosion resis-
tance.

aluminum bronze A copper-aluminum alloy,
usually with 3 to 11% aluminum; may contain
additional additives; has good corrosion resis-
tance and may be cast or coldworked.

aluminum door A door having aluminum
stiles and rails; usually glazed.

aluminum foil Very thin aluminum sheet (less
than 0.006 in. or 0.15 mm); usually used for
thermal insulation and vapor barriers.

aluminum oxide Same as alumina.

aluminum paint A paint made with alu-
minum paste and a film-forming vehicle (such as
a varnish); a good heat and light reflector; has
good water impermeability.

aluminum powder Small flakes of alu-
minum metal obtained by stamping or ball-
milling foil in the presence of a fatty lubricant,
such as stearic acid, which causes the flakes to
orient in a pattern to give high brilliance. Usu-
ally supplied in paste form wetted with mineral
spirits.

aluminum primer An aluminum-based
primer, 1 that has excellent water-resistant prop-
erties.

aluminum-silicon bronze An alloy con-
sisting chiefly of copper with aluminum and
silicon added to give it greater strength and
hardness.

aluminum window Any window constructed
principally of aluminum, the components of
which usually are extruded.

aluminum-zinc coating On a metal surface,
a corrosion-resistant coating having properties
similar to galvanizing.

alure, allure, alur A gallery or passage, as
along the parapets of a castle, around the roof of
a church, or along a cloister.

alure A

ALV

ALV Symbol for alarm valve.

alveated Having the vaulted shape of a beehive.

alveus In ancient Rome, a bath constructed in
the floor of a room, the upper part of it project-
ing above the floor, the lower part being sunk
into the floor itself.

ALY On drawings, abbr. for alloy.

amado In traditional Japanese architecture, a
type of shutter made of sliding wooden panels
which (when not in use) slide into a box-like
storage cabinet attached to the exterior of the
building at one side of the opening; usually set in
place in the evening.

ado

ambo, 1

ambrices In ancient Roman construction, the
cross laths inserted between the rafter and tiles
of a roof.

ambry, almary, almery, aumbry 1. A cup-
board or niche in a chancel wall for the utensils
of the Eucharist; an armarium. 2. A storage
place, storeroom, closet, or pantry.

AMB Abbr. for "asbestos mill-cut board."

ambient lighting In any given area, the gen-
eral background illumination.

ambient noise The all-encompassing, average
background noise associated with a given envi-
ronment, often a composite of sounds from
many sources near and far, of many different
types, e.g., the general background noise in a
neighborhood or in an auditorium.

ambient pressure In a water distribution sys-
tem, the normal operating pressure at any partic-
ular location in the system.

ambient temperature The temperature of
the surrounding air.

ambitus 1. A small niche in underground
Roman or Greek tombs, forming a receptacle for
a cinerary urn. 2. In the Middle Ages, such a
niche, but enlarged to admit a coffin. 3. In the
Middle Ages, the consecrated ground surround-
ing a church.

ambo, ambon 1. In early Christian churches,
a pulpit for reading or chanting the Gospels or
the Epistles. 2. In contemporary Balkan or
Greek churches, a large pulpit or reading desk.

ambry, 1

American Colonial Revival

ambulatory 1. A passageway around the apse of
a church, or for circumambulating a shrine. 2. A
covered walk of a cloister.

ambulatory, 2

ambulatory church A church having a
domed center bay which is surrounded on three

sides by aisles.

AMCA Abbr. for "Air Movement and Control
Association."

AMD On drawings, abbr. for "air-moving device."

amended water Water to which a surfactant
has been added.

amendment A modification to a building's
contract documents.

American basement A floor of a building
partly above and partly below grade level, often
serving as the entrance level to the building. Also
see basement. Also called a walk-out basement.

American bond Same as common bond; same
as English garden-wall bond.

American Bracketed style A term occa-
sionally used for the Italianate style.

American Chateauesque style See Chateau-
esque style.

American Colonial architecture A term
usually applied to colonial buildings constructed
in America by English immigrants to the New
World; often classified according to region in
America.

In early colonial New England, the typical
house was timber-framed with hewn-and-pegged

joints; exterior walls were sometimes covered
with hard plaster, then clad with clapboard
or weatherboards. Unpretentious houses com-
monly had a single room with a loft space above;
more prosperous houses, often one and a half or
two stories high and one or two rooms deep, usu-
ally were built on the hall-and-parlor plan, with
one room on each side of an interior wall con-
taining a massive, centrally located fireplace and
a large high chimney; on the facade, drops were
often suspended from the underside of an over-
hanging second floor. Many of these early houses
had a steeply pitched gable roof and a side gable,
or a hipped roof with eaves having no significant
overhang; unglazed window openings were cov-
ered with solid-wood shutters, later replaced by
narrow casement windows having small quar-
rels; heavy battened doors. Also see saltbox
house, stone ender, whale house. Occasionally
called Early Colonial architecture.

In the colonial South and along the mid-
Atlantic coast, single-room houses of the early
settlers were often similar to the one-room plan
houses in New England, with a clay-and-sticks
chimney. Later, as the houses became larger,
they usually followed a hall-and-parlor plan or a
center-hall plan. Exterior walls were usually
brick, with hand-split shingles on the roof; a
massive decorative brick or stone exterior chim-
ney at one or both gabled end walls, with cor-
beled chimney caps. Pent roofs were common in
the mid- Atlantic area. For colonial architecture
constructed by immigrants other than the
English, see Dutch Colonial architecture,
French Colonial architecture, German Colonial
architecture, Spanish Colonial architecture.
American Colonial Revival An architec-
tural mode usually based on architectural proto-
types in the English colonies in America, but
often including features not found or rarely
present in those prototypes. Buildings in this
classification are usually characterized by a
facade often featuring a Classical cornice;
cupola; widow's walk; colonial detailing; bevel
siding or a smooth brick wall finish with fine
joints; brickwork often set in a Flemish bond
pattern; splayed lintels; a hipped, gabled, or
gambrel roof covered with slate tiles or wood
shingles; louvered shutters; double-hung rect-
angular sash windows with multiple panes in
both the upper and lower sashes; symmetrically

American four-square house

arrayed windows in the facade; a fanlight over
the main entry door and sidelights on each side
of door; the front door commonly crowned by a
pediment, extending forward and supported on
columns so as to form an entry porch.

American four-square house 1. A one- or
two-story house having a square floor plan con-
sisting of four rooms (one in each corner), a
hipped roof, and an off-center entry door; most
popular from about 1905 to 1915. 2. A Prairie
box, primarily in the years between about 1900
to 1920, having a low-pitched hipped roof and a
symmetrical facade.

American Institute of Architects (AIA)
A professional organization, founded in 1857,
whose purpose is to establish and promote pro-
fessionalism and accountability on the part of its
members, and to promote architectural design
excellence. Address: 1735 New York Avenue
NW, Washington, DC 20006.

American International style See Interna-
tional style and Contemporary style.

American linden See basswood.

American Mansard style A seldom-used
synonym for Second Empire style. Also see
Mansard style.

American method of application A meth-
od of applying rectangular roofing shingles which
provides double coverage with a head lap, but no
side lap.

American National Standards Institute
An independent organization of trade associa-
tions, technical societies, professional groups,
and consumer organizations; establishes and
publishes standards; formerly known as the
United States of America Standards Institute
(USASI or ASI), and previously as the American
Standards Association (ASA).

American oriental carpeting An American
loom-made carpet, of Axminster or Wilton
weave, manufactured in color and pattern
designs similar to those of oriental rugs.

American Renaissance Revival A term
occasionally used for Italian Renaissance Revival.

American Rundbogenstil Same as Round
Arch style.

American Society of Landscape Archi-
tects (ASLA) The professional organization
of landscape architects in America, founded in

1899. Address: 636 Eye Street, NW, Washington,
DC 20008.

American Society for Testing and Materi-
als A nonprofit organization that establishes
standard tests and specifications for construction
materials; such tests and specifications usually are
referred to by the abbreviation ASTM followed
by a numerical designation. Address: 100 Bar
Harbor Drive, West Conshohocken, PA 19428.

American standard beam A type of I-beam
of hot-rolled structural steel; designated by the
prefix S placed before the size of the member.

American standard channel A C-shaped
structural member of hot-rolled structural steel;
designated by the prefix C placed before the size
of the member.

American standard channel

American standard pipe threads In the

US, standard pipe threads for commonly used
sizes of pipe for water, gas, or steam; formerly
called Briggs standard pipe threads.

American Standards Association See
American National Standards Institute.

Americans with Disabilities Act (ADA)
A federal law, enacted in 1990, requiring that
public accommodations be accessible to those
having physical disabilities; this law mandates
that existing physical barriers be replaced or
modified so there are no impediments to access
by the physically disabled. For detailed infor-
mation, write the US Equal Employment
Opportunities Commission, 1801 L Street,
NW, Washington, DC 20507. See American
National Standards Institute (ANSI) Standard
Al 17.1-1992. Also see Uniform Federal Acces-
sibility Standards and physical disability.

American table of distances A table giving
safe distances for the storage of explosives, as
approved by the Institute of the Makers of
Explosives.

American Tudor style See Tudor Revival.

amphitheater

American wire gauge, American standard
wire gauge, Brown and Sharpe gauge

A system used in the US for designating wire
diameter in electrical wiring or the thickness of
aluminum, brass, and copper sheets; ranges from
6/0 (0.58 in. or 16.3 mm) to 40 (0.0031 in. or
0.079 mm).

Amer Std Abbr. for "American Standard."

amino plastic Any plastic made of compounds
derived from ammonia.

ammeter An instrument for measuring the rate
of flow of electricity, usually expressed in amperes.

ammonia A chemical used as a refrigerant, esp.
in large low-temperature refrigeration systems (as
in ice skating rinks) because of its high efficiency.

ammonium chloride See sal ammoniac.

amoretto, amorino Same as cupid.

amorini Same as putti.

amorino, amoretto A winged cherub.

amorphous Said of rock having no crystal
structure.

amortizement The sloping top of a buttress or
projecting pier.

amortizement

amount of mixing The designation of the
extent of mixer action employed in combining
the ingredients for concrete or mortar; for sta-
tionary mixers: the mixing time; for truck mixers:
the number of revolutions of the drum or blades
at mixing speed, after the intermingling of the
cement with water and aggregates.

amp Abbr. for ampere.

ampacity The current-carrying capacity of a
wire or cable, expressed in amperes.

amperage The flow of electric current in a cir-
cuit, expressed in amperes.

ampere The International Standard unit for
electrical current. A unit of the rate of flow of
electric current; an electromotive force of 1 volt
acting across a resistance of 1 ohm results in a
current flow of 1 ampere.

amphiprostyle Marked by columns in porti-
coes only at the front and back (of a classical
temple), not on the sides.

amphiprostyle

amphistylar Said of a classical temple having
columns across the length of both sides or across
both ends.

amphitheater, amphitheater l.A circular,
semicircular, or elliptical auditorium in which a
central arena is surrounded by rising tiers of
seats. 2. (Brit.) The first section of seats in the
gallery of a theater. 3. Any outdoor theater, esp.
of the classical Greek type.

amphitheater

amphithura

amphithura A curtain divided in the center,
closing the entrance through the iconostasis of a
Greek church.

amplitude Of oscillation or vibration, the
maximum displacement from the mean position.

amusement park A commercially operated
park with entertainment features such as roller
coasters, shooting galleries, merry-go-rounds,
refreshment stands, etc.

amyl acetate, banana oil A solvent for lac-
quers and paints; has a strong banana-like odor.

amylin See dextrin.

anaglyph An embellishment carved or chased
in low relief. Also see bas-relief.

analemma 1. A retaining wall at the side of an
ancient Greek or Roman theater. 2. Any raised
construction which serves as a support or rest.

analogion, analogium l.A reading desk,
lectern, or ambo. 2. In the Eastern church, a
stand on which choir books rest.

anamorphosis A drawing which appears to be
distorted unless viewed from a particular angle
or with a special device.

anamorphosis

anatase See titanium dioxide.

anathyrosis A Greek method of fitting
masonry without mortar by carefully dressing
the contact edges of the blocks, leaving the cen-
ter rough and slightly recessed.

anchor, anchorage l.A device such as a
metal rod, wire, or strap, for fixing one object to
another, as specially formed metal connectors
used to fasten together timbers, masonry, trusses,
etc. 2. In prestressed concrete, a device to lock
the stressed tendon in position so that it will
retain its stressed condition. 3. In precast con-
crete construction, a device used to attach the
precast units to the building frame. 4. In slabs on
grade, or walls, a device used to fasten to rock or
adjacent structures to prevent movement of the
slab or wall with respect to the foundation, adja-
cent structure, or rock. 5. A support which holds
one end of a timber fast. 6. A device used to
secure a window or doorframe to the building
structure; usually adjustable in three dimensions;
also see doorframe anchor. 7. See jamb anchor,
masonry anchor, etc. 8. The anchor-shaped dart
in the egg-and-dart molding; also called anchor
dart. 9. A device used in a piping system to
secure the piping to a structure; typically provided
by a metal insert in an overhead concrete slab or
beam. 10. A wrought-iron clamp, of Flemish ori-
gin, on the exterior side of a brick building wall
that is connected to the opposite wall by a steel
tie-rod to prevent the two walls from spreading
apart; these clamps were often in the shape of

anchors, 1

Anchor

Hanger
rod

anchor, 9

medieval anchors, 10

ancient light

numerals indicating the year of construction, or
letters representing the owner's initials, or were
simply fanciful designs.

anchor beam In a typical Dutch barn in colo-
nial America, a massive horizontal timber that
spans the barn from one gable end to the oppo-
site end.

anchorage 1. In posttensioning, a device which
anchors the tendons to the posttensioned con-
crete member. 2. In pretensioning, a device used
to anchor the tendons temporarily during the
hardening of the concrete. 3. Same as anchor, 3.

anchorage bond stress The forces in a steel
bar divided by the product of the perimeter and
the embedment length.

anchorage deformation, anchorage slip
The shortening of tendons in prestressed concrete
due to the deformation of the anchorage or slip-
page of the tendons in the anchorage device
when the prestressing force is transferred to the
anchorage device.

anchorage device Any device used in
anchorage.

anchorage device

anchorage loss Same as anchorage deformation.

anchorage system A group of interacting

anchors and elements.
anchorage zone l.In posttensioning, the

region adjacent to the anchorage for the tendon
which is subjected to secondary stresses as a
result of the distribution of the prestressing

force. 2. In pretensioning, the region in which

transfer bond stresses are developed.
anchor block A block of wood, replacing a

brick in a wall to provide a nailing or fastening

surface.
anchor bolt, foundation bolt, hold-down

bolt 1. A steel bolt usually fixed in a building

structure with its threaded portion projecting;

used to secure frameworks, timbers, machinery

bases, etc. 2. See brick anchor.

anchor bolt

anchor cable A cable or line, one end of

which is held in a fixed position.
anchor dart See anchor, 8.
anchor fastener A mechanical device (such

as a bolt or spike) used to secure a timber or

wood framework.
anchored-type ceramic veneer Ceramic

veneer which is attached to a backing by grout

and nonferrous metal anchors; minimum overall

thickness is 1 in. (2.54 cm).
anchor iron Same as beam anchor.
anchor line Same as anchor cable.
anchor log A timber which serves as a dead man.
anchor pile A pile behind a retaining wall to

which tie-back rods or cables are connected.
anchor plate A square metal plate used as floor

tile in industrial plants.
anchor rod A threaded metal rod used with

various types of hangers to support ductwork,

piping, etc.
anchor store A store (usually a major chain

store or department store) in a shopping center

or mall whose presence attracts business to

smaller shops within the center.
anchor tie Same as anchor, 1.
ancient light (Brit.) A window which is

legally entitled to the continuous access to light

ancillary

by virtue of having had continuous access to
light for many years in the past.

ancillary One of a group of buildings having a
secondary or dependent use, such as an annex.

ancon, (pi.) ancones 1. A scrolled bracket or
console, 1 which supports a cornice or entabla-
ture over a door or window. 2. A projecting boss
on a column drum or wall block. 3. A cramp to
fasten blocks of stone.

ancon, 1

ancon, 2

anda The hemispherical dome of a stupa.

andiron One of a pair of metal supports for a log

in a fireplace.
andron, andronitis 1. In ancient Greece, the

part of a building used by men, esp. the banquet

room. 2. A passage beside the tablinum in a

Roman house.
anechoic room A room whose boundaries

absorb almost completely sound waves which

are incident upon them; practically no sound is

reflected from the boundaries.
anemometer An instrument for measuring the

velocity of airflow.
angel beam A hammer beam of a medieval

roof truss; so called because it often had an angel

carved on its surface.

angel light A small triangular light, 1 between
subordinate arches of the tracery of a window,
esp. in the English Perpendicular style.

angiosperm A class of seed plants (having
seeds enclosed in an ovary) which includes most
of the world's flowering plants.

angiportus In ancient Rome, a narrow road
passing between two houses or a row of houses,
or an alley leading to a single house.

angle 1 . The figure made by two lines that meet.
2. The difference in direction of such intersecting
lines, or the space within them. 3. A projecting
or sharp corner. 4. A secluded area resembling a
corner; a nook. 5. An L-shaped metal member;
an angle iron. 6. See bevel angle. 7. A fitting on
a gutter for rainwater which changes the gutter's
direction.

angle bar 1. An upright bar at the meeting of
two faces of a polygonal window, bay window, or
bow window. 2. An angle iron.

angle bead 1. A corner bead. 2. A strip, usu-
ally of metal or wood, set at the corner of a plas-
ter wall to protect the corner or serve as a guide
to float the plaster flush with it; a type of angle
staff.

angle bead, 2

angle blasting Sandblasting, or the like, at an
angle of less than 90°.

angle block, glue block A small block of
wood, triangular in cross section, which is used
to stiffen two intersecting pieces of wood at
right angles; for example, under the step of a
stair.

angle board A board whose surface is cut at
a desired angle; serves as a guide for cutting
and/or planing other boards at the same
angle.

angle float

angle bond A tie used to bond masonry work
at wall corners.

angle brace 1. A strip of material which is
fixed across a frame to make it rigid, as a wood
strip which is nailed temporarily across the
corners of a window frame or doorframe to
maintain squareness during shipment or in
handling before permanent installation; also
called an angle tie. 2. An angle iron. 3. A spe-
cial brace which is used for drilling where
there is insufficient room for an ordinary brace
handle to turn.

angle bracket A projecting bracket which is
not at right angles to the wall.

angle brick Any brick having an oblique shape
to fit an oblique, salient corner.

angle buttress One of two buttresses at right
angles to each other, forming the corner of a
structure.

angle capital A capital at a corner column,
esp. an Ionic capital where the four volutes

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angle capital

plan of an Ionic angle capital

project equally on the diagonals, instead of
being in two parallel planes; used by both Greeks
and Romans.

angle chimney A chimney placed so that the
sides of the chimney form an angle with the side
walls of a room.

angle cleat Same as angle clip.

angle clip A short strip of angle iron used to
secure structural elements at right angles.

angle closer A special-shaped brick used to
close the bond at the corner of a wall.

angle collar A cast-iron pipe fitting which
has a socket at each end for joining with the
spigot ends of two pipes that are not in align-
ment.

angle column A column placed at the corner
of a building, as at the corner of a portico; may
be freestanding or engaged.

angle corbel An L-shaped corbel plate form-
ing a right-angle bend, the vertical surface of
which is fastened to the wall; the horizontal
surface is used to support a building compo-
nent.

angled bay window A bay window that is tri-
angular in plan and protrudes outward from a
wall.

angled chimney stacks See diagonal chim-
ney stacks.

angle divider A square for setting or bisect-
ing angles; one side is an adjustable hinged
blade; when set at 90°, it can be used as a try
square.

angle dozer A bulldozer with its blade set at an
angle to push the earth to one side.

angledozer Same as bulldozer.

angled stair A stair whose successive flights are
at an angle other than 180° to each other (often
the angles are at 90°), with an intermediate plat-
form between them.

angle fillet A wooden strip, triangular in cross
section, which is used to cover the internal joint
between two surfaces meeting at an angle of less
than 180°.

angle fireplace A fireplace across one corner
of a room; for example, see fogon.

angle float A trowel having two edge surfaces
bent at 90°; used to finish corners in freshly poured
concrete and in plastering. (See illustration p. 38.)

angle gauge

angle float

angle gauge A template used to set or check
angles in building construction.

angle globe valve A type of globe valve

intended for use at a point in a water distribu-
tion system where the piping changes direction
by 90°; saves the cost of an extra elbow and
provides an additional point of control of water
flow.

angle hip tile An arris hip tile.

angle iron, angle bar An L-shaped iron or
steel bar or structural steel member.

angle joint A joint between two pieces of
lumber which results in a change in direction,
such as a dovetail joint or a mortise-and-tenon
joint.

angle lacing A system of lacing in which angle
irons are used in place of bars.

angle leaf In medieval architecture, a carved
claw or spur, 1 which projects from the lower
torus of a column, so as to cover one of the pro-
jecting corners of the square plinth beneath.

angle-lighting luminaire A luminaire whose
light distribution is asymmetric with respect to a
direction of specific interest.

angle modillion A modillion at the corner of a
cornice.

angle newel A landing newel.

angle niche A niche formed at the corner of a
building; common in medieval architecture.

angle of illumination The angle between the
axis of an illuminator and a perpendicular to the
surface being illuminated.

angle of repose The maximum angle with the
horizontal at which a mass of material, as in a cut
or embankment, will lie without sliding; the
angle between the horizontal and the maximum
slope that a soil assumes through natural
processes.

angle of rest Same as angle of repose.

angle paddle A hand tool used to finish a plas-
tered surface.

angle pier A pier, 2 at the intersection of two
walls, constructed on the external angle.

angle post In half-timber construction, the
corner post.

angle rafter A hip rafter.

angle rail A timber that is cut from a square rail
to form two lengthwise pieces which are triangu-
lar in cross section.

angle rib 1 . In decorative work, a molding that
ornaments an angle. 2. In Gothic architecture,
one of the diagonal ribs, 1 that divides each of
the rectangles of a vault.

angle ridge A hip rafter.

angle-roll Same as bowtell.

angle section A structural steel member hav-
ing an L-shaped cross section.

angle shaft l.A column within the right-
angled recesses of Norman door and window
jambs. 2. A decorative member, such as a colon-
nette or enriched corner bead, attached to an
external angle of a building.

angle staff, staff angle A vertical strip of
wood or metal at the exterior angle of two plas-
tered surfaces and flush with them; protects the
plastering and serves as a guide for floating the
plaster; a corner bead, 2.

angle stile A narrow strip of wood used to con-
ceal the joint between a wall and a vertical wood
surface which makes an angle with the wall, as at
the edge of a corner cabinet.

angle stone Same as quoin.

angle strut An angle-shaped structural mem-
ber which is designed to carry a compression
load.

anglet A groove, usually containing an angle of
90°.

angle tie See angle brace, 1.

angle tile A tile, 1 that forms an angle; used to
cover a hip, 1 (ridge) of a roof; sometimes used in
weather tiling (tile hanging) to cover the corner
of a building.

angle trowel A margin trowel.

Anglo-Saxon architecture

EL*

JJi

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1 ^r

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A, B, anglet

angle valve A valve for controlling the flow
of a liquid or air; the fluid leaves at right
angles to the direction in which it enters the
valve.

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PACKING

angle valve

angle volute See angle capital.

Anglo-Italian Villa style A term occasion-
ally used for the Italianate style.

Anglo-Palladianism An architectural move-
ment, primarily in England between 1710 and
1 760, set up in reaction to the Baroque style of
architecture; marked by the rediscovery of works
of Inigo Jones and the earlier works of Andrea
Palladio. Occasionally called Burlingtonian
style or Palladian Revival.

Anglo-Saxon architecture The pre-Roman-
esque architecture of England before the

Anglo-Saxon architecture

angstrom

Norman Conquest (1066 A.D.), which survived
for a short time thereafter; characterized by mas-
sive walls and round arches; a belt course or
pilaster strips; triangular arches; long-and-short
work.

angstrom A unit of length; used to express
electromagnetic wavelengths; 1 A= 10~ 10 meter =
Vio nanometer. Abbr. A.

angular aggregate Aggregate, the particles of
which possess well-defined edges formed at the
intersection of roughly planar faces.

angular capital Same as angle capital.
angular frequency (co) The frequency of a

periodic quantity multiplied by 271; expressed in
radians.

angular hip tile Same as angle tile.

angular pediment A pediment having a hori-
zontal cornice and slanting sides that meet in a
point at the top so as to form a triangle; also
called a triangular pediment.

angular pediment

anhydrite A natural mineral calcium sulfate,
used in the manufacture of portland cement to
control its set.

anhydrous calcium sulfate, dead-burnt
gypsum Gypsum from which all the water of
crystallization has been removed.

anhydrous gypsum plaster Plaster which
has a greater percentage of the water of crystal-
lization removed than normal gypsum plasters;
used as a finish plaster. Requires the addition of
an accelerator to produce a set.

anhydrous lime See lime.

animal black A black pigment made by char-
ring of animal bones; sometimes used in paints,
although carbon black generally is preferred for
tinting strength and blackness. Available in
three grades: boneblack, drop black, and ivory
black.

animal glue, hide glue A glue made from the
bones, hide, horns, and connective tissues of
animals; when used hot, it develops strong
bonds; has poor water resistance.

anisotropic Descriptive of a material (such as
wood) that does not have the same physical
properties in all directions.

ANL On drawings, abbr. for "anneal."

annealed glass Glass created by a process that
moves it, in a molten form, along a long oven
where it is heated and then slowly cooled under
controlled conditions, emerging as a flat, "fire
polished" glass product.

annealed tube See soft copper tube.

annealing A process of holding a material at an
elevated temperature, but below its melting
point, to permit the relieving of internal stresses
in the material.

annex, annexe A subsidiary structure near or
adjoining a larger principal building.

annexation The acquisition of new territory by
a governmental authority, such as a city or state.

annual plant A plant whose life cycle is com-
pleted in a single growing season.

annual rings

annual ring, growth ring A layer of wood

produced during one year of a tree's growth.
annular Said of a ring-shaped structure or object.

annular crypt A crypt in a church that has a
semi-circular ambulatory leading to the main
chamber, which contains a relic of a saint.

annular molding Any molding that is circular
in plan, such as the torus at the base of a column.

annular nail A nail with circular ridges around
its shaft; provides greater holding power than a
nail without such ridges.

antecabinet

annular vault A barrel vault in the shape of a
ring, instead of a straight line; covers a space of
which the plan is formed by the area between
two concentric circles, or any portion of such a
space.

annulated column A shaft or cluster of shafts

fitted, at intervals, with rings.
annulet A small molding, usually circular in

plan and square or angular in section; esp. one of

the fillets encircling the lower part of the Doric

capital above the necking.

anode In an electric system to protect under-
ground iron pipes or structures from electro-
chemical action, a metallic rod which is driven
in the ground; direct current is passed through
the rod to the earth, and then through the iron
pipe or structure, in a direction opposite to that
resulting from the electrochemical properties of
the soil.

anodic coating The surface finish resulting
from anodizing; may be transparent or colored by
the use of a dye or pigment in the anodizing
process.

anodize To provide a hard, noncorrosive, elec-
trolytic, oxide film on the surface of a metal, par-
ticularly aluminum, by electrolytic action.

anse de panier Same as basket-handled arch.

ANSI Abbr. for American National Standards
Institute.

anta (pi. antae) A pilaster or a rectangular pier
formed by a thickening at the end of a wall, usu-
ally projecting into a facade or portico; its capi-
tal and base usually differ from those on columns
within the portico. Antae usually occur in pairs,
with one on each side of the portico. If there are
columns within the portico that are between the
antae, they are said to be in amis. Also see distyle
in antis.

annulets: A, of a Doric capital. Shown enlarged in lower
figure

antae A

annunciator 1. A signaling device, usually
electrically operated, that emits an audible sig-
nal and/or a visual indication under selected cir-
cumstances; for example, it may sound an alarm
in the case of fire or unauthorized entry. 2. See
car annunciator.

ANOD On drawings, abbr. for anodize.

anta cap The capital of an anta.

antebellum Dating before or existing before
the US Civil War (1861-1865).

antecabinet A room, often spacious and ele-
gant, leading to a private audience room or cab-
inet.

antechamber

antechamber 1 . A room preceding a chamber.
2. A foyer, lobby, or vestibule.

antechapel A separate entrance space, as a
porch or vestibule, in front of a chapel.

antechoir The space, more or less enclosed,
between the inner and outer gates of the choir
screen.

antechurch A deep narthex at the front of a
church, usually with a nave and side aisles.

antecourt An entrance court or outer court
which precedes the principal court, as at Ver-
sailles; a forecourt.

antefix 1 . A decorated upright slab used in clas-
sical architecture and derivatives to close or
conceal the open end of a row of tiles which
cover the joints of roof tiles. 2. A similar orna-
ment on the ridge of a roof.

antefix, 1

antemural The outerworks or wall surrounding
and protecting a castle.

antenave A narthex or porch of any descrip-
tion leading into the nave of a church.

antepagment 1. A stone or stucco which serves
as a decorative dressing that enriches the jambs
and head of a doorway or window; an architrave,
2. 2. A jamb or molded architrave of a door.

antependium A wooden hanging which was
once displayed over, and in front of, the altar of
a medieval church.

antepodium A seat behind the dais in a choir,
reserved for the clergy.

anteport A preliminary portal; an outer gate or
door.

anteportico An outer porch or a portico in
front of the main portico in a classical temple.

anterides In ancient Greek and Roman archi-
tecture, a structure to strengthen another; a

antepagment

type of buttress placed against an outer wall,
esp. in subterranean construction.

anterides

anteroom A room adjacent to a larger, more
important one; frequently used as a waiting
area.

ante-temple The narthex of an ancient temple.

antique crown

anthemion, honeysuckle ornament A

common Greek ornament based upon the
honeysuckle or palmette. Used singly on stelae
or antefixes, or as a running ornament on
friezes, etc.

anthemion

antic, antic work A grotesque sculpture con-
sisting of animal, human, and foliage forms
incongruously run together and used to decorate
molding terminations and many other parts of

antidesiccant Material applied to plants prior
to transplanting to reduce the amount of mois-
ture lost from transpiration.

antiflooding interceptor Same as backwater
valve.

antifreeze sprinkler system A wet-pipe
sprinkler system whose piping is filled with an
antifreeze solution. When the system is acti-
vated, the antifreeze solution is discharged, fol-
lowed by a discharge of water from the water
supply to which it is connected.

antifriction bearing Any bearing having the
capability of reducing friction effectively.

antifriction latch bolt In builders' hardware,
a latch bolt designed to reduce friction as the
bolt engages the strike plate.

antimonial lead, hard lead, regulus metal
An alloy containing 10 to 25% antimony and
the balance lead; antimony increases the tensile
strength and hardens the lead; used in roofing,
tank lining, and cladding, 2.

antimony oxide A white opaque pigment
used in paints and plastics to provide flame-
retardant properties. It has better opacity than
extenders but is not as good as titanium
dioxide.

antimony yellow See Naples yellow.

antiparabema One of two chapels at the
entrance end of a Byzantine church.

antipumping A feature that prevents the
reclosing of a circuit breaker until the cause of
the closing has been corrected.

antique crown, eastern crown A heral-
dic device consisting of a headband with an
indefinite number of pointed rays projecting
from it.

medieval architecture. Sometimes synonymous
with grotesque or arabesque.

anticorrosive paint A paint formulated with
a corrosive-resistant pigment (such as lead chro-
mate, zinc chromate, or red lead) and a chemical
and moisture-resistant binder; used to protect
iron and steel surfaces.

anticum The front of a classical building, as dis-
tinguished from the posticum; same as pronaos.

antique crown

antique glass

antique glass A textured cylinder glass of

uneven thickness, used primarily in stained glass
windows; similar in characteristics to the stained
glass of the Middle Ages.

antiquing A technique of handling wet paint,
by combing, graining, or marbling, so as to
expose parts of the undercoat; also called
broken-color work.

antiquum opus Same as opus incertum.

antis, in See in antis.

anti-sing lamp Same as low-noise lamp.

anti-siphon An adjective applied to a mechan-
ical device, such as a valve, that eliminates
siphonage.

anti-siphon trap See deep-seal trap.

anti-siphonage vent Same as back vent.

anti-siphon vacuum breaker A device (or
means) for preventing back siphonage.

antislip paint A paint with a high coefficient
of friction, caused by addition of sand, wood
flour, or cork dust; used on steps, porches, and
walkways to prevent slipping.

antismudge ring A frame attached around the
perimeter of a ceiling-mounted air diffuser,
which minimizes the formation of rings of dirt
on the ceiling.

antistatic agent An agent which minimizes
static electricity in plastics; may consist of
chemical additives or metallic devices con-
nected to an electrical ground.

anti-sun glass See coated glass and tinted
glass.

AP Abbr. for "access panel."

APA Abbr. for "American Plywood Associa-
tion."

apadana The columnar audience hall in a
Persian palace.

apartment 1 . A room or suite of rooms
designed to be lived in, containing at least one
bathroom; is separated from, and is usually one
of, many similar units within a multiple
dwelling. 2. A building containing at least three
such dwelling units; an apartment house. Also
see efficiency apartment, garden apartment,
apartment hotel.

apartment hotel 1. A hotel which rents liv-
ing quarters suitable for light housekeeping
and supplies hotel services. 2. An apartment

house which supplies living quarters suitable
for light housekeeping and has public dining
facilities.

apartment house See apartment, 2.

apartments (Brit.) A group of rooms used as a
dwelling by one person or one family.

APC On drawings, abbr. for "acoustical plaster
ceiling."

apex In architecture or construction, the high-
est point, peak, or tip of any structure.

apex stone, saddle stone The uppermost
stone in a gable, pediment, vault, or dome; usu-
ally triangular, often highly decorated.

apodyterium A room in Greek or Roman
baths, or in the palaestra, where the bathers
or those taking part in gymnastic exercises,
undressed and dressed.

aponsa A shed roof having rafters that are let
into, or rest upon, a wall.

apophyge l.That part of a column where
the shaft of the column springs from its base or
where the shaft terminates at its capital;
usually molded in a concave sweep; also called
a scape or conge. 2. The hollow (i.e., scotia)
beneath the echinus of some Classical
capitals.

apophyge, 1

apophyge, 2

aposthesis Same as apophyge.
apostilb A unit of luminance equal to

candela per square meter.
apotheca In ancient Greece and Rome, a

storeroom of any kind, but esp. one for storing

wine.

(1/n)

approved equal

appareille The slope or ascent to the platform
of a bastion.

apparent brightness See brightness.

apparent candlepower Of an extended light
source at a specified distance: the candlepower
of a point source which produces the same illu-
mination at that distance.

apparent density l.The mass per unit vol-
ume of in-place thermal insulation. 2. The mass
per unit volume (or the weight per unit volume)
of a material, including the voids which are
inherent in the material.

APPD On drawings, abbr. for approved.

appentice, pent, pentice A minor structure
built against the side of a building, with a roof of
single slope; a penthouse, 3.

appentice

appliance, appliance equipment Any de-
vice (other than industrial) which utilizes gas or
electricity as a fuel to produce air-conditioning,
heat, light, refrigeration, or to perform one or
more functions such as dishwashing; usually built
in a standard size or type and installed or con-
nected as a unit.

appliance lamp An electric lamp designed for
high-temperature service.

appliance outlet See outlet.

appliance panel In electric systems, a metal
housing containing two or more devices (such as
fuses) for protection against excessive current in
circuits which supply portable electric appli-
ances with current.

appliance regulator A regulator for control-
ling and maintaining a uniform pressure of gas
supplied to an appliance.

application for payment The contractor's
written request for payment of amount due for
completed portions of the work, 1 and, if the
contract so provides, for materials delivered and
suitably stored pending their incorporation into
the work.

application life Same as working life.

applied molding A molding that is nailed on,
laid on, or otherwise fastened to a surface, rather
than cut into the surface itself.

applied ornament Same as applique, 2.

applied trim Supplementary and separate dec-
orative strips of wood or moldings applied to the
face or sides of a frame, as on a doorframe.

applique l.An accessory decorative feature
applied to an object or structure. 2. In ornamen-
tal work, one material affixed to another.

appraisal An evaluation or estimate (preferably
by a qualified professional appraiser) of the mar-
ket or other value, cost, utility, or other attribute
of land or other facility.

approach-zone district In zoning, a classifi-
cation which identifies all that area outward
from the end of, or approach to, a runway in
which the height of structures or other hazards
to aircraft is restricted.

approval drawing In building construction,
one of the drawings furnished by a manufacturer
to a purchaser for his approval. Such an approval
affirms that the manufacturer has correctly
interpreted all contractual requirements.

approved 1. Referring to materials, devices, or
construction accepted by the authority having
jurisdiction, by reason of tests or investigations
conducted by it or by an agency satisfactory to the
authority, or by reason of accepted principles or
tests by national authorities or technical or scien-
tific organizations. 2. Referring to occupancy or
use, accepted by the authority having jurisdiction
by reason of the submission of adequate proof of
conformity with the basic requirements of the
code under which the authority functions.

approved equal Material, equipment, or
method approved by the architect for use in
the work, 1 as being acceptable as an equiva-
lent in essential attributes to the material,

approved ground

equipment, or method specified in the contract
documents.

approved ground A ground (such as the steel
framework of a building, a concrete-encased
electrode, or a ground ring) that meets the
requirements of the National Electrical Code or
other applicable code.

approving authority The individual agency,
board, department, or official established and
authorized by a political subdivision (e.g., state,
province, county, city, or parish) which is cre-
ated by law to administer and enforce specified
requirements.

APPROX On drawings, abbr. for "approxi-
mate."

appurtenance l.Any built-in, nonstructural
portion of a building, such as doors, windows,
ventilators, electrical equipment, partitions,
etc. 2. An incidental property right, as a right-
of-way.

appurtenant structure A structure attached
to the exterior of a building or erected on the
roof, usually designed to support service equip-
ment or to support a billboard or the like.

APPX On drawings, abbr. for "appendix."

apron 1. A flat broad piece of finished lumber
or trim placed directly under a windowsill. 2. A
flat piece of wood mounted under the base of a
cabinet. 3. Same as counterflashing. 4. Same as
apron flashing. 5. Paneling on the exterior of a
building which serves as a protection against
weather or as a decorative feature. 6. That por-
tion of a concrete slab which extends beyond
the face of a building on adjacent ground, as the
extension of a garage floor. 7. A vertical panel at
the back of a sink or lavatory. 8. In a theater,
that part of a stage which projects into the audi-
ence area beyond the proscenium and curtain
line; a forestage.

apron flashing 1. The flashing that covers the
joint between a vertical surface and a sloping
roof, as at the lower edge of a chimney. 2. The
flashing that diverts water from a vertical surface
into a gutter.

apron lift A hydraulic or mechanical lift which
extends the fixed apron of a stage in front of a
proscenium opening.

apron lining The piece of boarding which cov-
ers the rough apron piece of a staircase.

apron molding See apron, 2.

apron piece, pitching piece A horizontal
wood beam, fixed into a wall and projecting hor-
izontally, which supports the ends of carriage
pieces, roughstrings, and joists at the landings of
a wooden staircase.

apron rail A lock rail having a raised ornamen-
tal molding.

apron sink A deep-sided sink whose front and
sides are extended downward from the upper
edge, forming an apron around the sink.

apron stage In a proscenium theater, an exten-
sion of the fixed apron (in front of a proscenium
opening) by means of a platform or by an apron
lift.

apron wall In an exterior wall, a panel which
extends downward from a windowsill to the top
of a window below.

apse A semicircular (or nearly semicircular) or
semipolygonal space, usually in a church, termi-
nating an axis and intended to house an altar.

apse

apse aisle An aisle or ambulatory extending

around an apse or chevet.
apse chapel A chapel opening from an apse;

such a radial chapel is a conspicuous feature of

French Gothic architecture.
apsidal Pertaining to an apse or similar to one.

araeostyle

apse aisle

aqueduct

apsidiole A small apsidal chapel, esp. one pro-
jecting from an apse. There are often several
chapels projecting from the apse.

apsidiole

apsis The semicircular termination of any rect-
angular chamber; an apse.

APT l.On drawings; abbr. for apartment. 2.
Abbr. for Association for Preservation Technology.

apteral Descriptive of a classical temple or
similar building that has no columns along the
sides but may have a portico at one or both
ends.

APW On drawings, abbr. for "architectural pro-
jected window."

aqueduct A channel for supplying water;
often underground, but treated architecturally
on high arches when crossing valleys or low
ground.

aquifer A water-bearing formation of gravel,
permeable rock, or sand that is capable of provid-
ing water, in usable quantities, to springs or wells.

aquila A tympanum decorated with carvings.

AR l.On drawings, abbr. for "as required." 2.
On drawings, abbr. for "as rolled."

ara Any Classical structure elevated above the
general ground level which is used to make offer-
ings to the gods.

arabesque 1. Intricate overall pattern of geo-
metric forms or stylized plants used in Muslim
countries. 2. Overall decorative pattern of acan-
thus scrolls, swags, candelabrum shafts, animal or
human forms, on panels or pilasters, in Roman
and Renaissance architecture. 3. A species of
ornament of infinite variety used for enriching flat
surfaces or moldings, either painted, inlaid, or
carved in low relief.

arabesque

Arabic arch A horseshoe arch.
araeostyle Same as areostyle; see intercolumni-
ation.

araeosystyle

araeosystyle, areosystyle Alternately systyle
and araeostyle; having an intercolumniation
alternately of two and four diameters.

arbitration The binding resolution of disputes
by one or more neutral persons (usually called
"arbitrators"), as a substitute for judicial pro-
ceedings; may be invoked only by agreement of
the parties to the dispute, but such agreement
may be arrived at before there is an actual dis-
pute, as, for example, through a clause in a con-
tract between them, or after a dispute has
arisen. Arbitration proceedings characteristi-
cally are less formal than those in court, and
the rules of evidence and most rules of substan-
tive law that would be invoked by a court are
not applied.

arbor 1. A light, open structure having a lattice
framework, usually supporting intertwined vines
or flowers; a shaded, leafy recess, often formed by
tree branches. 2. See counterweight arbor. 3.
The rotating shaft of a circular saw, spindle
molder, shaper, etc.

arboretum An informally arranged garden,
usually on a large scale, where trees are grown for
display, educational, or scientific purposes.

arc 1 . The luminous column of gas in an arc
discharge; caused by the flow of electric cur-
rent between separated electrodes in a gas.
2. See carbon-arc spotlight. 3. Any part of
the circumference of a circle. 4. An angular
measure.

area custodiae In ancient Roman architec-
ture, a type of cell for the confinement of
prisoners.

arcade l.A line of counterthrusting arches
raised on columns or piers. Also see blind
arcade, coupled arcade, interlacing arcade,
intersecting arcade, surface arcade, wall
arcade. 2. A covered walk with a line of such
arches along one or both long sides. 3. A cov-
ered walk with shops and offices along one
side, and a line of such arches on the other.
Also see stoa. 4. A covered walk, lit from the
top, lined with shops or offices on one or more
levels.

arcading A line of arches, raised on columns,
that are represented in relief as decoration of a
solid wall; sometimes seats are incorporated in
the composition.

!l',:.J

P7 - Wt± W

arcading

arcae In ancient Roman architecture, the gut-
ters of the cavaedium.

arcature 1. Arcading. 2. An ornamental,
miniature arcade.

arc-boutant Same as flying buttress.

arc cutting A process of cutting or removing
metal by melting it with the heat produced
between an electrode and the metal being cut.

arc de cloitre A groined vault having reen-
trant angles.
arc de triomphe Same as triumphal arch.

arc discharge An electric discharge character-
ized by the production of light, high cathode-
current densities, and a low voltage drop at the
cathode.

arc doubleau An arch, usually very massive,
carried across a wide space, to support a groined
vault or to stiffen a barrel vault.

arcella A cheese room, in medieval architecture.

arc formeret The wall arch or wall rib, or the
corresponding rib coming next to the arcade
between nave and aisle, or the like, as in Gothic
vaulting.

arc gouging A groove or bevel formed in metal
as a result of arc cutting.

arch A construction that spans an opening; usu-
ally curved; often consists of wedge-shaped blocks
(voussoirs) having their narrower ends toward the
opening. Arches vary in shape, from those that
have little or no curvature to those that are acutely
pointed. For special types of arches, see acute arch,
anse de panier, arriere-voussure, back arch,
basket-handle arch, bell arch, blind arch, camber
arch, catenary arch, cinquefoil arch, compound
arch, cusped arch, diminished arch, discharging
arch, Dutch arch, elliptical arch, equilateral arch,

arched construction

arch: Ex Estrados; In intrados; K keystone; S springers;
v voussoirs

flat arch, Florentine arch, foil arch, French arch,
garden arch, gauged arch, Gothic arch, horseshoe
arch, inverted arch, jack arch, keel arch, keystone
arch, lancet arch, Mayan arch, memorial arch,
miter arch, Moorish arch, ogee arch, pointed arch,
Queen Anne arch, raking arch, rampant arch,
rear arch, relieving arch, round arch, rowlock
arch, safety arch, sconcheon arch, secondary
arch, segmental arch, semicircular arch, semiellip-
tical arch, shouldered arch, skew arch, straight
arch, three-centered arch, transverse arch, trefoil
arch, triangular arch, triumphal arch, Tudor arch,
two-centered arch.

ARCH. On drawings, abbr. for architect, archi-
tecture, or architectural.

archarium Same as archivium.

arch band Any narrow elongated surface form-
ing part of, or connected with, an arch.

arch bar A curved wrought-iron or steel bar
used to support the weight of the masonry above
a fireplace or window opening.

arch barrel roof See barrel vault,
arch beam Same as arched beam.

arch brace A curved brace, usually used in
pairs to support a roof frame and give the effect
of an arch.

arch brick, compass brick, featheredge
brick, radial brick, radiating brick, radius
brick, voussoir brick l.A wedge-shaped
brick used in arch or circular construction; its two
larger faces are inclined toward each other. 2.
Extremely hard-burnt brick from an arch.

arch buttant Same as flying buttress.

arch buttress Same as flying buttress.

arch buttress

arch center Formwork to support the voussoirs

of an arch during construction.
arch corner bead A corner bead that is cut on

the job; used to form and reinforce the curved

portion of an arch opening.

arched barrel roof Same as barrel roof.

arched beam A beam whose upper surface is
slightly curved.

arched butment Same as flying buttress.

arched buttress Same as flying buttress.

arched construction A method of construc-
tion relying on arches and vaults to support walls
and floors.

arched corbel table

arched corbel table In early Christian and
Romanesque architecture and their derivatives,
a corbel table (often near the top of a wall) com-
posed of small blind arches that are regularly
punctuated by pilaster strips.

arched dormer A dormer having an approxi-
mately semicylindrical roof; the head of the
upper sash in the dormer may be either round-
topped or flat-topped.

arched tomb A tomb chest that lies within an

arched niche in a wall.
archeion See archivium.

archeria In medieval fortifications, an aperture
through which an archer or longbowman might
discharge arrows.

archiepiscopal cross A cross with two trans-
verse arms, the longer one nearer the center.

arching 1 . The transfer of stress from a yielding
part of a soil mass to adjoining less-yielding or
restrained parts of the mass. 2. A system of
arches. 3. The arched part of a structure.

architect 1. A person trained and experienced
in the design of buildings and the coordination
and supervision of all aspects of the construc-
tion of buildings. 2. A designation reserved,
usually by law, for a person or organization pro-
fessionally qualified and duly licensed to per-
form architectural services, including analysis of
project requirements, creation and develop-
ment of the project design, preparation of draw-
ings, specifications, and bidding requirements,
and general administration of the construction
contract. An architect usually renders services
that require the application of art, science, and
the aesthetics of design to the construction of
buildings, including their components and
appurtenances and the spaces around them, tak-
ing into account the safeguarding of life, health,
property, and public welfare; often includes con-
sultation, evaluation, planning, the provision of
preliminary studies, designs, and construction
documents; and may also include construction
management, and the administration of con-
struction documents.

architect-engineer An individual or firm
offering professional services as both architect
and engineer; term generally used in govern-
ment contracts, particularly those with the fed-
eral government.

architect-in-training Same as intern architect.

architectonic Related or conforming to tech-
nical architectural principles.

architect's approval The architect's written
or imprinted acknowledgment that materials,
equipment, or methods of construction are
acceptable for use in the work, 1, or that a con-
tractor's request or claim is valid.

architect's scale A scale having graduations
along its edges so that scale drawings can be
measured directly in feet (or meters); often tri-
angular in shape.

architectural 1. Pertaining to architecture, its
features, characteristics, or details. 2. Pertaining
to materials (such as stone, mosaic, or bronze)
used to build or ornament a structure.

architectural area Total floor area of a build-
ing calculated from its exterior surfaces or from
the center line of a common wall between two
buildings; usually excludes open terraces. Roofed
areas such as porches or arcades are calculated at
one-half actual area.

architectural barrier An architectural fea-
ture that creates inaccessibility or prevents the
free movement of disabled people within a
building.

Architectural Barriers Act An Act passed
by the US Congress in 1968 requiring that build-
ings financed with federal funds, and/or owned or
leased by the federal government, be constructed
or modified so that they are accessible to, and
can be used by, physically disabled people.

architectural bronze An alloy containing
57% copper, 40% zinc, 2.75% lead, 0.25% tin;
used for extruded moldings and forgings. Not
technically a bronze.

architectural coating A coating which is
usually intended for on-site application of inte-
rior and/or exterior surfaces of buildings.

architectural concrete 1. Reinforced con-
crete used for structural and ornamental work. 2.
In nonconcrete frame structures, the exposed
concrete used for aesthetic effects.

architectural details The relatively small ele-
ments of design and finish of a building.

architectural drawing One of a number of
drawings prepared by an architect for a con-
struction project, e.g., plans, elevations, and
details.

architrave block

architectural fountain A system of pumps,
tubes, pipes, controls, valves, and nozzles
through which water is forced under pressure to
produce ornamental jets, spouts, or showers;
often lighted for special nighttime effects.

architectural glass Any of several types of
configurated glass.

architectural hardware All hardware used
in building construction, especially that which is
attached to movable elements such as doors and
windows; also called finish hardware.

architectural ironmongery (Brit.) Same as

architectural hardware.
architectural millwork, custom millwork

Ready-made millwork as obtained from the mill,
especially fabricated to meet the specifications
for a particular job, as distinguished from stan-
dard or stock items or sizes.
architectural mode An inexact classification
for buildings that share selected architectural
features but, unlike an architectural style, may
not share consistency of design, form, or orna-
mentation with other buildings similarly classi-
fied. When such buildings seemingly emulate an
earlier prototype (for example, American Colo-
nial Revival), important architectural details
that characterize the prototype are often either
omitted or exaggerated in size or importance;
furthermore, other design elements may be
added (such as a type of dormer, chimney, or
window) that never existed in the prototype; or
characteristic building materials of the proto-
type may be replaced with newer types of mate-
rials. Compare with architectural style.

architectural projected window A window
in which the basic frame and hinged sash (venti-
lator, 2) members are made of heavier steel than
that used in a commercial projected window.

architectural section See section, 2.

architectural sheet metal See sheet metal.

architectural style A classification character-
izing buildings that share many common attri-
butes, including similarity in general appearance,
in the arrangement of major design elements in
ornamentation, in the use of materials, and in
form, scale, and structure. Such styles are often
related to a particular period of time, geographi-
cal region, country of origin, or religious tradi-
tion, or to the architecture of an earlier period.

Often, a term that includes the word style (such
as Santa Fe style) is an architectural mode rather
than an architectural style.

architectural terra-cotta A hard-burnt, glazed
or unglazed clay unit used in building construc-
tion; plain or ornamental; machine-extruded or
hand-molded; usually larger in size than brick or
facing tile. Also see ceramic veneer.

architectural volume The cubic content of a
building calculated by multiplying the floor area
by the height. For foundations, the average
depth of footing to the finish floor is used. For
roofs (other than flat roofs), the average height
is used.

architecture 1 . The art and science of design-
ing and building structures, communities, or open
areas, in keeping with aesthetic and functional
criteria. 2. Structures built in accordance with
such principles.

architrave l.In the classical orders, the lowest
member of the entablature; the beam that spans
from column to column, resting directly upon
their capitals. Also see order. 2. The ornamental
moldings around the faces of the jambs and lintel
of a doorway or other opening; an antepagment.

architrave bead A metal stop bead which is

fixed to a wall next to a door or window open-
ing; covered by the architrave.
architrave block Same as skirting block.

architrave cornice

architrave cornice An entablature in which
the cornice rests directly on the architrave, the
frieze being omitted.

archivium In ancient Greece and Rome, a
building in which archives of a city or state were
deposited; also called archeion or tabularium.

archivolt An architrave modified by being car-
ried around a curved opening instead of a rect-
angular one; an ornamental molding or band of
moldings on the face of an arch following the
contour of the extrados.

archivolt

archivoltum A medieval conduit or receptacle
for waste materials, as a sewer or cesspool.

arch order l.In Roman architecture, arches
enframed by engaged columns and entablatures.
2. In medieval architecture, successive vertical
planes of arches and colonettes set one within
another.

arch order, 1

arch rib l.In Romanesque architecture, a
transverse rib crossing the nave or aisle at right
angles to its length. 2. A principal load-bearing
member of a ribbed arch.

arch ring In an arched structure, the curved
member that sustains the principal load.

arch stone Same as voussoir.

arch surround A seldom-used term for a dec-
orative border around an arch; same as archivolt.

arch truss A truss having an arched upper chord
(concave downward) and a straight bottom chord;
there are vertical hangers between the two chords.

archway A passage through or under an arch,
especially when long, as under a barrel vault.

archway

arc light A high-intensity light source pro-
duced by an arc, usually, between two metal
electrodes or between two carbon rods; also see
carbon-arc spotlight.

arcosolium An arched recess or sepulchral
cell in a Roman subterranean burial place or
catacomb.

arcs doubleaux Same as arch band.

arc spotlight See carbon-arc spotlight.

arcuated Based on, or characterized by, arches
or archlike curves or vaults. It is common to
distinguish between trabeated (beamed) and
arcuated buildings.

arcuated lintel A Syrian arch.

arcuatio In ancient Rome, a structure formed
by means of arches or arcades and employed to
support a construction of any kind, such as an
aqueduct.

argillite

arcus ecclesiae In medieval architecture, the
arch by which the nave of the church was
divided from the choir or chancel.

arcus presbyterii In medieval architecture,
the arch over the tribune, 2.

arcus toralis The lattice separating the choir
from the nave in a basilica.

arcus triumphalis A triumphal arch.

ARC W, ARC/W On drawings, abbr. for arc
weld.

arc weld A weld in which the heat of fusion is
supplied by an electric arc.

arc welding The joining of metal parts by
fusion, in which the necessary heat is produced
by means of an electric arc, sometimes accompa-
nied by the use of a filler metal and/or the appli-
cation of pressure.

WELDIHC C*BLf-

arc welding: above, with bare electrodes; below, circuit

are An area equal to 100 sq m.

area 1 . Measurement of surface within speci-
fied boundaries. 2. Space either within or out-
side a structure or location, designated for a
specific purpose, as recreation and/or parking
area. 3. An uninterrupted interior space. 4. An
areaway. 5. The cross-sectional area of steel
reinforcement.

area divider A raised edge on a roof membrane
that divides it into smaller areas.

area drain A receptable designed to collect sur-
face or rainwater from an open area.

area efficiency Of a building, the ratio of the
net usable floor area (or the net rentable area) to
the gross floor area.

area grouting The grouting of an area in
which (closely spaced) shallow holes have been
drilled in a pattern in bedrock. This grouting has
the effect of strengthening the upper portions of
the bedrock and making it less pervious.

area light 1. A source of light with significant
dimensions in two directions, such as a window
or luminous ceiling. 2. A light used to illuminate
large areas.

area method A method of estimating probable
total construction cost by multiplying the
adjusted gross floor area by a predetermined cost
per unit of area.

area of refuge An area where individuals who
are in a building may gather safely in case of fire
and/or smoke; usually an outdoor area adjacent
to the building, or an area protected by fire-rated
walls.

area of rescue assistance Same as area of
refuge.

area of steel See area, 5.

area separation wall A fire-rated partition
designed to prevent the spread of fire from an
adjoining occupancy.

area 'wall A retaining wall around an areaway.

areaway An open subsurface space adjacent to
a building used to admit light and air or as a
means of access to a basement or crawl space.

arena l.An acting space of any shape sur-
rounded by seats. 2. A type of theater not having
a proscenium, the spectators' seats, rising in
tiers, wholly surrounding the stage. 3. The
sanded central area in a Roman amphitheater or
circus, surrounded by the seats. 4. Any building,
indoor or outdoor, for sports events, etc.

arenaceous Composed primarily of sand; sandy.

arena theater See arena, 2.

arena vomitory A vomitory through a section
of seats which provides a special access, for
actors, to an arena stage.

areostyle, araeostyle See intercolumniation, 2.

argillaceous Composed primarily of clay or
shale; clayey.

argillite A rock containing chiefly clay materi-
als; derived from claystone, siltstone, or shale;

ARI

used locally as building stone, although rarely
produced commercially.

ARI Abbr. for "Air-Conditioning and Refrigera-
tion Institute."

aris See arris.

ark An ornamental, enclosed repository in a
synagogue for the scrolls of the Torah.

arkose Sandstone containing 25% or more feld-
spar grains in abundance; used as building stone.

armarium Same as ambry.

armature l.The heavy-current winding of a
motor or generator. 2. The winding in a solenoid
or relay. 3. Structural ironwork in the form of
framing or bars (commonly employed in
medieval buildings) used to reinforce slender
columns, or to consolidate canopies or hanging
members such as bosses, and in tracery.

arm conveyor A conveyor for building mate-
rials in the form of an endless belt or chain, to
which are attached projecting arms or shelves
which carry the materials.

armored cable, metal-clad cable Two or

more individually insulated electric conductors
having a common outer protective covering of
metal. Also see BX.

armored clamp A fitting which grips the
armor of a cable where the armor terminates or
where the cable enters a junction box.

armored faceplate A tamperproof faceplate
or lock front, mortised in the edge of a door to
cover the lock mechanism.

armored front In builders' hardware, a lock
front which consists of two plates: the under
plate (an unfinished plate fastened to the case)
and the finish plate (a plate which covers the
cylinder setscrews, thus protecting them from
tampering, and which is fastened to the under
plate); used on mortise locks.

armored-plate door A door fabricated of
tempered glass.

armored plywood Plywood which is faced on
one or both sides with metal sheeting.

armored wood Metal-clad wood.

armor plate A metal plate which protects the

lower part of a door from kicks and scratches;

similar to a kickplate but covering the door to a

greater height, usually 39 in. (1 m) or more from

the bottom of the door.

armor-plate glass See bullet-resisting glass,
tempered glass.

armory 1 . A building used for military training
or storage of military equipment. 2. A weapons-
manufacturing plant.

aromatic cedar See eastern red cedar.

arrectarium In Classical Roman construction,
an upright pillar or post which is load-bearing.

arrester 1 . At the top of an incinerator or
chimney, a wire screen which prevents sparks
or burning material from leaving the stack.
2. See lightning arrester. 3. See surge arrester.
4. See water-hammer arrester. 5. A lightning
arrester. 6. A grease trap.

arriere-voussure, rear arch 1. A rear vault;

an arch or vault in a thick wall carrying the
thickness of the wall, esp. one over a door or
window frame. 2. A relieving arch behind the
face of a wall.

arriere-voussure

arris, aris l.An external angular intersection
between two planar faces (an edge), or two
curved faces, as in moldings or between two
flutes on a Doric column or between a flute and
the fillet on an Ionic or a Corinthian column. 2.
The sharp edge of a brick.

arris fillet A triangular batten used to tilt up
the lowest course of slates on a roof, at the edge
of gutters.

arris gutter A V-shaped wooden gutter fixed to
the eaves of a building.

arris hip tile, angle hip tile A special roof
tile having an L-shaped cross section, made to fit
over the hip of a roof.

arris rail A rail of triangular section, usually
formed by slitting diagonally a strip of square
section; the broadest surface forms the base.

Art Moderne

arrissing tool A tool similar to a float, but hav-
ing a form suitable for rounding an edge of
freshly placed concrete.

arris tile Any angularly shaped tile.

arris-trenched A housing, 1 that is cut
obliquely through an arris.

arrisways, arriswise Diagonally, in respect
to the manner of laying tiles, slates, bricks, or
timber.

arrow diagram In CPM, an arrangement of
arrows, representing activities, that describe a
project.

arrow loop, loophole A vertical slit for
archers in medieval fortification walls, with
jambs deeply splayed toward the interior.

arrow loop

arrow slit Same as arrow loop.
ARS On drawings, abbr. for asbestos roof
shingles.

ART. On drawings, abbr. for "artificial."

Art Deco A decorative style stimulated by the
Paris Exposition International des Arts Decora-
tifs et Industrie lies Modernes of 1925, widely
used in the architecture of the 1930s, including
skyscraper designs such as the Chrysler Building
in New York; characterized by sharp angular or
zigzag surface forms and ornaments. Also re-
ferred to as Style Moderne.

artemiseion A building or shrine dedicated to
the worship of Artemis.

arterial street A street that provides a direct
route for long-distance travel within different
parts of a city.

arterial vent A vent serving a building drain
and a public sewer.

artesonado In Hispanic architecture, a ceiling,
usually having a paneled appearance, comprised
of sections and/or interlacing strips.

art glass A type of colored glass used in win-
dows during the late 19th and early 20th cen-
turies; characterized by unusual combinations of
hues and special effects in transparency and
opaqueness.

article l.A subdivision of a document. 2. In
project specifications, the primary subdivision of
the section, often further subdivided into para-
graphs, subparagraphs, and clauses.

articulated drop chute A drop chute, for a
falling stream of concrete, which consists of a
vertical succession of tapered metal cylinders, so
designed that the lower end of each cylinder fits
into the upper end of the one below.

articulated structure A structure which per-
mits relative motion to occur between its parts
(e.g., by means of one or more sliding or hinged
joints).

artifact See building artifact.

artificial Made to resemble a natural material or
object, for example, faux marbre.

artificial daylight Light provided by an artifi-
cial source which has a spectral distribution
approximating that of natural daylight at a cor-
related color temperature.

artificial horizon A device for indicating the
horizon, as a bubble, pendulum or the flat sur-
face of a liquid.

artificially dried See kiln-dried.

artificial marble See artificial stone.

artificial monument A relatively permanent
object used to identify the location of a survey
station or corner.

artificial sky A dome (usually hemispherical)
illuminated by concealed light sources; used to
illustrate and study daylighting techniques on
architectural models placed near the center of
the hemisphere.

artificial stone A mixture of stone chips or
fragments, usually embedded in a matrix of mor-
tar, cement, or plaster; the surface may be
ground, polished, molded, or otherwise treated
to simulate stone; variously called art marble,
artificial marble, cast stone, marezzo, patent
stone, and reconstructed stone.

art marble See artificial stone.

Art Moderne An architectural style found
principally in houses constructed in the 1930s,

Art Nouveau

following the earlier Art Deco style. Common
characteristics may include smooth stuccoed
wall surfaces; flat roofs; architectural details
that emphasize the horizontal appearance of
the building; rounded exterior corners; ribbon
windows that may continue around a corner;
glass blocks; an asymmetrical facade. The
jagged version of this style is sometimes called
Zigzag Moderne. Also see International style.
Compare with Art Deco and Streamline
Moderne.

Art Nouveau A style of decoration in archi-
tecture and applied art developed principally in
France and Belgium toward the end of the 19th
cent.; characterized by organic and dynamic
forms, curving design, and whiplash lines. The
German version is called Jugendstil, the Austrian
variant Sezession; in Italy one speaks of Stile Lib-
erty, in Spain of Modernismo.

Arts and Crafts Movement A group of
architects and artisans who emphasized the
importance of craftsmanship and high stan-
dards in all architectural details; greatly influ-
enced by the outstanding work of William
Morris and his company of craftsmen near
London. Beginning in the late 19th century
and extending into the early 20th century, this
movement had a significant impact in Amer-
ica on the Prairie style with its low-pitched
roofs and widely overhanging eaves, and on
the Craftsman style. In particular, excellent
craftsmanship and superior detailing was
embraced in the designs of the architects
Charles Sumner Greene (1868-1957) and his
brother Henry Mather Greene (1870-1954) of
Pasadena, California, whose work exemplified
architectural details carried to a high art.

art 'window A term sometimes applied to a
window having its upper and lower sashes of dif-
ferent sizes, with the upper sash containing a
number of small panes of colored glass.

arx The fortress or citadel of an ancient town.

AS Abbr. for automatic sprinkler.

ASA Abbr. for "American Standards Associa-
tion;" see American National Standards
Institute.

asarotum A type of painted pavement used by
the ancient Romans before their use of mosaic
work.

asb 1. Abbr. for apostilb. 2. Abbr. for asbestos.

ASBC Abbr. for "American Standard Building
Code."

asbestos, asbestos fiber Fine, flexible, non-
combustible, inorganic fiber obtained from nat-
ural hydrous magnesium silicate; can withstand
high temperatures without change; a poor heat
conductor; is fabricated into many forms either
alone or with other ingredients. A recognized
health hazard.

asbestos abatement, asbestos removal
The procedures used in eliminating the release
of asbestos fibers or in removing materials con-
taining asbestos (e.g., the process of encapsula-
tion). Also see air monitoring, HEPA filter, and
wet cleaning.

asbestos blanket Asbestos fibers (alone or in
combination with other fibers) stitched, bonded,
or woven into flexible blanket form; used for
high-temperature insulation or for fire and flame
barriers.

asbestos board See asbestos-cement board.

asbestos-cement board, asbestos-cement
wallboard, asbestos sheeting A dense,
rigid, board containing a high proportion of
asbestos fibers bonded with portland cement;
resistant to fire, flame, and weathering;
has low resistance to heat flow. Used as a
building material in sheet form and corrugated
sheeting.

asbestos-cement cladding Asbestos-cement
board and component wall systems, directly sup-
ported by wall framing, forming a wall or wall
facing.

asbestos curtain, fire curtain, safety cur-
tain A curtain which closes the stage of a
theater from the auditorium automatically in
case of fire, preventing the spread of flame and
smoke; usually fabricated of woven asbestos
and steel wire, it may be nonrigid, semirigid, or
rigid.

asbestos felt A product made by saturating
felted asbestos with asphalt or other suitable
binder, such as a synthetic elastomer.

asbestos fiber See asbestos.

asbestos joint runner, pouring rope An

asbestos rope, wrapped around a pipe and then
clamped in position; used to hold molten lead
which is poured in a caulked joint.

ashpan

ASM5T0S
SUNNER

asbestos joint runner

asbestos plaster A fireproof insulating mate-
rial generally composed of asbestos with ben-
tonite as the binder.

asbestos roofing Roofing or wall cladding
sheets made of asbestos cement; may be plain,
corrugated, or variously patterned. Also see
asbestos cement board.

asbestos roof shingle A fire-resisting roofing
shingle, composed largely of asbestos.

asbestos runner Same as asbestos joint runner.

asbestos structural roofing Heavy asbestos-
cement board directly supported by roof fram-
ing, forming a roof deck and providing a roof
surface for cladding.

as-built drawing A working drawing as modi-
fied during construction; includes a record of
concealed items (such as conduits for building
services), thereby providing information for
future reference. Also called record drawings.

ASC Abbr. for "asphalt surface course."

A»scale In sound-level meters, a weighting net-
work, widely used to measure the noise levels in
buildings or communities. The A-scale provides
meter readings that correlate better with subjec-
tive judgments of noise than do readings of sound
pressure levels (which are also taken with a sound
level meter, but without a weighting network).

ASCE Abbr. for "American Society of Civil
Engineers."

ascendant See chambranle.

as-constructed See as-built drawing.

ash A hard, strong, straight-grained hardwood
of the eastern US having good shock resistance
and bending qualities; used as flooring, trim, and
decorative veneer.

ash dump An opening in the floor of a fire-
place or firebox through which ashes are swept
to an ashpit below.

ash house In colonial America, a small depen-
dency for storing ashes that were used primarily
for making soap.

ashlar 1. Squared building stone. 2. Ashlar
masonry. 3. A vertical stud between the floor
beams and rafters of a garret.

ashlar anchor Same as, or functioning as, a
cramp.

ashlar brick, rock-faced brick A brick
whose face has been hacked to resemble roughly
hacked stone.

ashlaring 1. Ashlars, collectively. 2. In garrets,
the short wood upright pieces between the floor
beams and rafters, to which wall lath is attached.

ashlar line A horizontal line at the exterior
face of a masonry wall.

ashlar masonry Masonry composed of rect-
angular units of burnt clay or shale, or stone,
generally larger in size than brick and properly
bonded, having sawn, dressed, or squared beds
and joints laid in mortar.

ashlar masonry: A, random-range quarry-faced ashlar;
B, random-range dressed-faced ashlar; C, coursed quarry-
faced ashlar; D, coursed dressed ashlar with margin draft;
E, bonder in ashlar; /, rubble filling back of ashlar

ashlar piece A vertical stud between the floor

beams and rafters of a garret.
ashlar veneer A veneer wall constructed of

ashlar masonry.
ashlering See ashlaring.
ashpan A metal receptacle beneath a grating

for collection and removal of ashes.

ashpit

ashpit A chamber located below the fireplace
or firebox for the collection and removal of

ashes.

ashpit door A cast-iron door providing access
to an ashpit for ash removal.

ASHRAE Abbr. for "American Society of
Heating, Refrigerating and Air-Conditioning
Engineers."

ASI Abbr. for "Architects and Surveyors In-
stitute."

Asiatic base A type of Ionic base; consists of a
lower disk with horizontal fluting or scotias
(there may be a plinth below the disk) and an
upper torus decorated with horizontal fluting on
relief; developed in Asia minor.

Asiatic water closet A water closet which has
its bowl nearly flush with the floor so that the
user adopts a squatting position; widely used in
some parts of Asia.

ASID Abbr. for "American Society of Interior
Designers."

asistencia In Spanish Colonial architecture, a

chapel usually having no permanent priest but
relying on the part-time assistance of visiting
padres.

asistencio In Hispanic Colonial architecture, a
contributing chapel.

askarel A synthetic electrically insulating liq-
uid which is nonflammable; when decomposed

by an electric arc, the gaseous products also are
nonflammable.
ASLA Abbr. for American Society of Land-
scape Architects.

ASME Abbr. for "American Society of
Mechanical Engineers."

aspasticum An apartment or place adjoining
the ancient churches or basilicas in which the
bishop or presbyters received visits of devotion or
in which ceremonies or business was conducted.

aspect The direction which a building faces
with respect to the points of a compass.

aspect ratio 1 . In any rectangular configura-
tion (such as the cross section of a rectangular
duct), the ratio of the longer dimension to the
shorter. 2. In a rectangular configuration, the
ratio of the long-side to the short-side.

aspersorium A holy-water stoup or font.

asphalt 1 . A dark brown to black cementitious
material, solid or semisolid, in which the pre-
dominating constituents are bitumens which
occur in nature. 2. A similar material obtained
artificially in refining petroleum; used in built-
up roofing systems as a waterproofing agent. 3. A
mixture of such substances with an aggregate for
use in paving.

asphalt binder course See binder course, 1.

asphalt block A paving block composed of a
mixture of 88 to 92% crushed stone and the bal-
ance asphaltic cement.

asphalt cement Asphalt that is refined to
meet specifications for paving, industrial, and
special purposes; see asphaltic cement.

asphalt color coat An asphalt surface
treatment with a cover of mineral aggregate
which has been selected to produce a desired
color.

asphalt concrete See asphaltic concrete.

asphalt cutter A powered machine having a
rotating abrasive blade; used to saw through
bituminous surfacing material.

asphalt-emulsion slurry seal A mixture of
slow-setting emulsified asphalt, fine aggregate,
and mineral filler, with water added to produce a
slurry consistency.

asphalt felt See breather-type asphalt felt.

asphalt filler See asphalt joint filler.

asphalt prepared roofing

asphalt fog seal An asphalt surface treat-
ment consisting of a light application of liq-
uid asphalt without a mineral aggregate
cover.

asphalt heater A piece of equipment for rais-
ing the temperature of bitumen used in paving;
usually the bitumen circulates through tubes
inside a chamber heated by a burner.

asphaltic base course In asphalt pavement, a
foundation layer consisting of mineral aggregate
bound together with asphaltic material.

asphaltic cement, asphalt cement A spe-
cially prepared asphalt, free of water and mate-
rial foreign to asphalt; contains less than 1% ash;
must be heated to a fluid condition for use; an
asphalt specially prepared as to quality and con-
sistency for direct use in the manufacture of
bituminous pavements.

asphaltic concrete, asphalt paving, black

top A mixture of asphalt and graded aggregate
widely used as paving material over a prepared
base; normally placed, shaped, and compacted
while hot, but can be prepared for placement
without heat. Also see cold mix.

asphaltic felt See asphalt prepared roofing.

Also see the specific type of felt, as mineral-
surfaced felt, sanded flux-pitch felt, etc.

asphaltic macadam A pavement similar to
macadam but having asphalt as the binder in
place of tar.

asphaltic mastic, mastic asphalt A viscous
mixture of asphalt and a filler material such as
fine sand or asbestos; hardens when exposed to
air; used as an adhesive, as a sealant at joints,
and in waterproofing.

asphalting The process of applying asphalt for
various construction purposes, as in waterproof-
ing basements and roof decks.

asphalt intermediate course Same as binder
course, 1 .

asphalt joint filler An asphaltic product used
for filling cracks and joints in pavement and
other structures.

asphalt lamination A laminate of sheet mate-
rial, such as paper or felt, which uses asphalt as
the adhesive.

asphalt leveling course A course (of an
asphalt- aggregate mixture) of variable thickness

used to eliminate irregularities in contour of an
existing surface, prior to the placement of a
superimposed layer.

asphalt macadam See asphaltic macadam.

asphalt mastic See asphaltic mastic.

asphalt overlay One or more courses of
asphalt construction on an existing pavement;
generally includes an asphalt leveling course to
correct the contour of the old pavement.

asphalt paint A liquid asphaltic product some-
times containing small amounts of other materi-
als such as lampblack, aluminum flakes, and
mineral pigments.

asphalt panel See premolded asphalt panel.

asphalt paper A paper sheet material that has
been coated, saturated, or laminated with
asphalt to increase its toughness and its resis-
tance to water.

asphalt pavement A pavement consisting of
a surface course of mineral aggregate, coated and
cemented together with asphalt cement on sup-
porting courses.

asphalt pavement sealer A compound
applied to asphalt pavements to protect the sur-
face from deterioration, from weathering, and
from petroleum products.

asphalt pavement structure All of the

courses of asphalt-aggregate mixtures placed
above the subgrade or improved subgrade.

asphalt paving See asphaltic concrete.

asphalt plank A plank which is fabricated of a
mixture of asphalt fiber and mineral filler, often
reinforced with steel or fiberglass mesh; some-
times contains mineral grits to provide a sandpa-
per texture.

asphalt prepared roofing, asphaltic felt,
cold-process roofing, prepared roof-
ing, rolled roofing, rolled strip roofing,
roofing felt, sanded bituminous felt,
saturated felt, self-finished roofing felt
A roofing material manufactured by saturating
a dry felt with asphalt and then coating the
saturated felt with a harder asphalt mixed with
a fine mineral, glass-fiber, asbestos, or organic
stabilizer; available in the form of rolls. All or
part of the weather side may be covered with
mineral granules or with powdered talc or
mica. The reverse side is covered with a mate-
rial suitable to prevent sticking in the roll. The

asphalt prime coat

WOOD
DECK

■ STARTER STRIP
Installing asphalt prepared roofing

granule-surfaced material may be used as cap
sheet in built-up roofing.

asphalt prime coat An initial application of
an asphalt primer, usually as preparation for a
superimposed treatment or construction.

asphalt primer A liquid material of low vis-
cosity which upon application to a nonbitumi-
nous surface is completely absorbed; used to
waterproof existing surfaces and to prepare them
as a base for an asphalt course.

asphalt roofing See asphalt-prepared roofing.

asphalt seal coat A bituminous coating, with
or without aggregate, applied to the surface of a
pavement to waterproof and preserve the surface
and to improve the texture of a previously
applied bituminous surface.

asphalt- shingle nail Same as roofing nail.

asphalt shingles, composition shingles,
strip slates Shingles manufactured from sat-
urated roofing felts (rag, asbestos, or fiber glass)
coated with asphalt and having mineral granules
on the side exposed to the weather.

asphalt soil stabilization The treatment of
naturally occurring nonplastic or moderately
plastic soil with liquid asphalt at normal temper-
atures to improve the load-bearing qualities of
the soil.

asphalt surface course A top course of
asphalt pavement.

asphalt surface treatment The application
of asphaltic materials to any type of pavement
surface or road surface, with or without a cover
of mineral aggregate.

asphalt tack coat A light coating of liquid
asphalt on an existing asphalt surface or on a
Portland cement concrete surface; used to ensure
a bond between the old surface and the overlay-
ing course.

TAB TAB NOTCH

STARTER COURSE

ROOFING FELT UNDERLAY

asphalt shingles: above, an asphalt shingle strip;
below, installing asphalt shingles

asphalt tile A resilient, low-cost floor tile com-
posed of asbestos fibers, finely ground limestone
fillers, mineral pigments, and asphaltic or
resinous binders. Requires waxing and buffing;
set in mastic over wood or concrete subfloor; is
not greaseproof unless specially treated.

asphaltum 1. Natural asphalt. 2. In painting,
asphalt from residues of crude mineral oil.

aspiration In an air-conditioned room, the
pulling of room air into the moving air-stream
which is discharging from a diffuser.

aspirator A device which draws a stream of
liquid or air through it by means of suction
which is produced by the flow of a fluid through
an orifice.

ASR Abbr. for "automatic sprinkler riser."

Assam psychrometer A psychrometer, shiel-
ded from radiation, in which the air is blown
over the bulbs of the two thermometers with a
small fan.

ASSE Abbr. for "American Society of Sanitary
Engineering."

assemblage of orders Same as supercolumni-
ation; also see orders.

Assyrian architecture

assembling bolt A threaded bolt for holding
together temporarily the several parts of a struc-
ture during riveting.

assembly area Same as assembly space.

assembly building A building used for the
gathering of persons for the purposes of amuse-
ment, deliberation, dining, drinking, education,
entertainment, instruction, or awaiting trans-
portation.

assembly occupancy Occupancy of a
room, hall, or building by people gathered for a
purpose, such as church, restaurant, or bus
station.

assembly drawing An engineering drawing of
a complete unit, usually including detail draw-
ings of its components.

assembly space A gathering place (such as an
auditorium, exclusive of a stage) that is occupied
by numbers of persons during major periods of
occupancy; some building codes consider every
tier of seating in an auditorium to be a separate
assembly space.

asser In ancient carpentry: l.The ribs or brack-
ets of an arched ceiling. 2. The purlins or rafters
of a roof. 3. A beam or joist.

assessed valuation The value of a property as
determined by a municipality for real estate tax
purposes; often this valuation is less than the
true market value of the property.

assessment A tax, charge, or levy on property:
1. as a means of computing real estate tax; 2. to
pay for specific services or improvements.

assessment ratio Of a property, the ratio
between its market value and its assessed
value.

assignment 1. The transfer of a legal right. 2.
In the case of a lease, the transfer of the right
of the tenant to the entire property leased and
for the entire term remaining; also see sub-
lease.

assidua That part of a church in which the altar
is placed.

assize 1. A cylindrical block of stone forming
one unit in a column. 2. A course of
stonework.

associate In an architectural firm, a member of
an architect's staff who has a special employ-
ment agreement.

associate architect, associated architect

An architect who has a temporary partnership,
joint venture, or employment agreement with
another architect to collaborate in the perfor-
mance of services for a specific project or series
of projects. Also see joint venture.

assommoir A gallery built over a door or pas-
sage of a fortified place, from which stones and
heavy objects could be hurled down on the
enemy.

ASST On drawings, abbr. for "assistant."

assumption of mortgage The purchaser of
property may promise the vendor that he will
assume the obligation to keep up the mortgage
payments. In such event, the mortgagee may
generally enforce this promise against the pur-
chaser, and in addition to his right to foreclose
in the event of nonpayment the mortgagee may
also recover from the purchaser (or from the
vendor) any deficiency between the proceeds
of the foreclosure sale and the amount still
owing on the mortgage. Also see subject to
mortgage.

Assyrian architecture Architecture of the
Assyrian empire (centered between the Tigris
and Upper and Lower Zab rivers in southwest
Asia); was expressive of its might, as conquerors
of Mesopotamia and much of the adjacent
countries between the 9th and 7th centuries
B.C. Mud brick was used as the building mate-
rial, although stone was available; stone was
used only for carved revetments and monumen-
tal decorative sculptures. Excavations have

Assyrian architecture: colored tiling from Khorsabad

astler

wmmmm .

mmmmwmmm

Assyrian architecture: pavement slab at Nimrud
(end of 9th cent. B.C.)

Assyrian architecture: decorative relief

uncovered large palaces and temple complexes
with their ziggurats as well as extensive fortifi-
cations.

astler Old English term for ashlar.

ASTM A non-profit technical society (formerly
known as the American Society for Testing and
Materials) that develops and publishes stan-
dards, definitions of materials, methods for
testing materials, recommended installation
practices, and specifications for materials.

ASTM portland cement One of eight classi-
fications of portland cement standardized by the
ASTM.

astragal 1 . A bead, usually half-round, with a fil-
let on one or both sides. It may be plain, but the
term is more correctly used to describe the classi-
cal molding consisting of a small convex molding
decorated with a string of beads or bead-and-reel
shapes. 2. A plain bead molding. Also called
roundel, baguette, or chaplet. 3. A member, or
combination of members, fixed to one of a pair of
doors or casement windows to cover the joint
between the meeting stiles and to close the clear-
ance gap; provides a weather seal, minimizes the
passage of light and noise, and retards the passage
of smoke or flame during a fire. Also see overlap-
ping astragal, split astragal.

astragal, 1 : in Greek architecture

c3a

Assyrian architecture: head

An overlapping astragal, 3

astragal front A lock front which is shaped to
fit the edge of a door having an astragal molding.

astragal joint A spigot-and-socket joint used
on a lead downspout (or the like), where the
socket incorporates ornamental moldings called
astragals.

astreated Decorated with star-like ornaments.

astylar Columnless; usually describing a facade
without columns, pilasters, or the like.

atrium

asylum A building or group of buildings that
serves as a refuge for the mentally ill.

AT. l.Abbr. for asphalt tile. 2. On drawings,
abbr. for "airtight."

atadura In Mayan architecture, a facade mold-
ing, above and below a continuous horizontal
decorative frieze on the exterior of a building.

ataracea Inlaid woodwork of various colors.

ATC l.On drawings, abbr. for architectural
terra-cotta. 2. On drawings, abbr. for "acoustical
tile ceiling."

atelier l.An artist's workshop. 2. A place
where artwork or handicrafts are produced by
skilled workers. 3. A studio where the fine arts,
including architecture, are taught.

ATF On drawings, abbr. for "asphalt-tile floor."

at grade Said of that part of a structure which is
at the same elevation as the adjacent finished
ground level.

Athenaeum A temple or place dedicated to
Athene, or Minerva; specifically an institution
founded at Rome by Hadrian for the promotion
of literary and scientific studies, and imitated in
the provinces.

atlantes See atlas.

atlas, pi. atlantes A figure (or figures) of a man
used in place of a column to support an entabla-
ture; also called a telamon.

atmospheric pressure, barometric pres-
sure The pressure exerted by the earth's
atmosphere; under standard conditions equal to
14.7 lb per sq in. (1.01 X 10 6 pascals) equivalent
to the pressure exerted by a column of mercury
29.9 in. (76.0 cm) high.

atmospheric-pressure steam curing Same
as atmospheric steam curing.

atmospheric steam curing The steam
curing of concrete or cement products at atmo-
spheric pressure, usually at a maximum ambi-
ent temperature between 100 to 200°F (40 to
95°C).

atmospheric-type vacuum breaker A
backflow preventer containing a float check,
check seat, and an air inlet port. As water flows
through this device, it causes the float check to
rise off a seat, thereby permitting the flow of
water. If pressure is lost upstream or if the flow of
water is turned off, the float check falls, thereby
allowing air to enter the line and preventing
backflow.

Air Inlet Port

Float Check

atm Abbr. for "atmosphere."

atmospheric burner A gas burner in a fur-
nace in which combustion air is supplied at
atmospheric pressure.

Shut Off Valve

atmospheric-type vacuum breaker

atomization The formation of tiny droplets

or a very fine spray, as produced by impinging

jets of air on a small stream of paint in spray

painting.
atomizing-type humidifier A humidifier in

which tiny particles of water are introduced into

a stream of air.
atrio A walled forecourt in California mission

architecture.
atriolum 1. In ancient Rome, a small atrium. 2.

A small antechamber forming the entrance of a

tomb.
atrium 1 . The main hall of an ancient Roman

house, containing an opening to the sky

atrium tetrastylum

atrium, 1

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atrium, 2

(compluvium) through which rainwater falls to
a tank or cistern below (impluvium). 2. In a
contemporary building, a large vertical space,
often centrally located, that connects three or
more floors and creates a sense of spaciousness.
atrium tetrastylum An atrium, 1, supported
by four columns, one at each corner of the
impluvium.

attached column An engaged column.

attached garage l.A garage which has at
least one wall (or part of one wall) in common
with a building. 2. A garage which is connected
to a building, as by a covered porch.

attached house A house that is joined to one
(or more) adjacent house(s) by a party wall.

attached pier Same as engaged pier.

attachment plug A device which is inserted
into a receptacle to establish the electric con-
nection between the conductors which are
wired to the receptacle and the conductors of
the flexible cord attached to the plug.

attemperator See coil.

attenuation See sound attenuation.

attenuator See sound attenuator.

Atterberg limits In plastic soils, the water
contents (determined by standard tests) which
define the boundaries between the different
states of consistency of plastic soils. Also see liq-
uid limit, plastic limit, shrinkage limit.

Atterberg test A test for determining the plas-
ticity of soils.

attic l.A garret. 2. In classic building, a story
built above the wall cornice. 3. (cap.) Pertaining
to the district of Attica in Greece. 4. The orna-
mental construction above an entablature; often
decorated. 5. The space between the ceiling
framing of the topmost story and the underside
of the roof framing.

attic, 2: of St. Peter's, Rome; A, attic of main edifice;
B , attic of the dome

Attic base The base of a column of the Ionic
order consisting of an upper torus and a lower

authority having jurisdiction

^..-

Attic base

torus, with a scotia and two narrow fillets

between them.
attic fan A propeller fan used to exhaust the air

within an upper space of a house (such as a garret) .
attic order Small pillars or pilasters decorating

the exterior of an attic, 2.

attic story See attic, 2.

attic tank An open tank which is installed
above the highest plumbing fixture in a building
(e.g., in the attic) and which supplies water to
the fixtures by gravity; the filling of the tank is
controlled by a float valve.

Atticurge Said of a doorway having jambs
which are inclined slightly inwards, so that the
opening is wider at the threshold than at the
top.

attic ventilator A mechanical fan, located in
the attic space of a residence; usually moves
large quantities of air at a relatively low
velocity.

attorney-in-fact A person authorized to act
for or in behalf of another person or organiza-
tion, to the extent prescribed in a written instru-
ment known as a power of attorney.

aud Abbr. for auditorium.

audio accumulator An audio listening device
used to detect sounds of breaking and entering a
building or a secure area within a building. False
alarms are minimized by a circuit design that
delays activation of an alarm until a predeter-
mined number of sound detections have been
"accumulated" within a selected time period.

audio frequency Any frequency of oscilla-
tion of a sound wave which is audible; usually in
the range between 15 and 20,000 Hz (cycles per
second).

audio-visual aids Equipment and/or materials
used in training, demonstrations, or teaching,
which employ sight and sound simultaneously.

auditorium That part of a theater, school, or
public building which is set aside for the audi-
ence for listening and viewing.

auditorium plan A plan, 1 employed in church
architecture where the plan of the sanctuary
somewhat resembles a common plan of a modern
auditorium.

auditorium seating Manufactured row chairs
for stepped, level, or inclined floors in rooms or
areas occupied by an audience.

auditory In ancient churches, that part of the
church where the people usually stood to be
instructed in the gospel; now called the nave.

auger 1 . A hand-held carpenter's tool for boring
holes in wood, similar to, but larger than, a gim-
let; has a long steel bit usually not larger than 1
in. (25 mm) in diameter. 2. A rotary drill, usu-
ally powered, for cutting circular holes in earth
or rock.

auger bit A bit having a square tang, fitted into
and rotated by a brace; used for drilling holes in
wood.

augered pile A concrete pile which is cast-in-

place in a hole drilled by an auger; may be belled

at the bottom; suitable in dry soil.
Augustaeum A building or temple dedicated

to the deified Augustus.
aula In ancient architecture, a court or hall, esp.

an open court attached to a house.
auleolum A small church or chapel.
aumbry See ambry.
aureole A pointed oval frame or glory around

the head or body of a sacred figure; the radiance

surrounding it. (See illustration p. 66.)
auricular Said of the shape of an ornament of

organic and dynamic forms that resemble the ear.

authority See administrative authority.

authority having jurisdiction A federal,
state, local, or other regional department, or an
individual such as a fire chief, fire marshal,
chief of a fire prevention bureau (or labor
department or health department), building
official, electrical inspector, or other individual
having statutory authority. For insurance pur-
poses, the "authority having jurisdiction" may
be an insurance inspection department or rat-
ing bureau, or other representative of an insur-
ance company. In many circumstances the

AUTO

AUkf.v

s \ V\\\ * , i, ' w s ( /< /<* /

property owner or a delegated agent assumes
the role of the authority having jurisdiction; at
government installations, the commanding
officer or departmental official may be the
"authority having jurisdiction."
AUTO On drawings, abbr. for "automatic."

autoclave A pressure vessel in which an envi-
ronment of steam at high pressure may be pro-
duced, usually at a high temperature; used in the
curing of concrete products and in the testing of
hydraulic cement for soundness.

autoclave curing Steam curing of concrete
products, sand-lime brick, asbestos cement prod-
ucts, hydrous calcium silicate insulation prod-
ucts, or cement in an autoclave at maximum
ambient temperatures generally between 340
and420°F(170and215°C).

autoclaved aerated concrete A lightweight
concrete usually made by adding aluminum
powder or calcium carbide to concrete mortar
which is subject to autoclave curing.

autoclaving cycle 1. In autoclave curing, the
time interval between the start of the tempera-
ture-rise period and the end of the blowdown
period. 2. A schedule of the time and tempera-
ture-pressure conditions of periods which make
up the cycle.

auto court A motel.

autogenous healing A natural process of
closing and filling cracks in concrete or mortar
while it is kept damp.

autogenous volume change The change in
volume produced by continued hydration of
cement, exclusive of effects of external forces or
change of water content or temperature.

autogenous welding A type of welding in

which the metals are usually united without the
use of flux, 1 .

automatic Said of a door, window, or other
opening protective device that is so constructed
and arranged that, when actuated by a predeter-
mined temperature or rise in temperature, it will
operate as intended.

automatic batcher A batcher for concrete
which is actuated by a single starter switch,
opens automatically at the start of the weighing
operations of each material, and closes automat-
ically when the designated weight of each mate-
rial has been reached.

automatic circuit breaker See circuit breaker.

automatic circuit recloser A self-controlled
device for automatically interrupting and reclos-
ing an alternating current circuit with a prede-
termined sequence of opening and reclosing,
followed by resetting, hold closed, or lockout
operation.

automatic closing device See closing
device.

automatic control valve A valve designed
to control the flow of steam, water, gas, or other
fluids, by means of a variable orifice which is
positioned by an operator in response to signals
from a sensor or controller.

automatic door l.A power-operated door
that closes when subject to an abnormally high

automatic fire vent

ambient temperature, an unusual rate of temper-
ature rise, or an abnormal smoke condition. 2. A
power-operated door that opens when a person
or automobile approaches.
automatic door bottom A movable plunger,
in the form of a horizontal bar at the bottom of a
door, which drops automatically when the door
is closed; when closed, a horizontal protruding
operating rod strikes the door jamb, thereby
actuating the plunger, sealing the threshold and
reducing noise transmission.

Door

Automatic
plunger

Felt Or rubber gasket

V//////77//////,

automatic door bottom

OPERATING'
ROD

automatic door bottom

automatic dry-pipe sprinkler system A
sprinkler system in which the piping up to the
sprinkler heads is either filled with compressed

air or air at atmospheric pressure; the water sup-
ply is controlled by an acceptable dry-pipe valve;
also see dry-pipe sprinkler system.

automatic dry standpipe system A stand-
pipe system in which all piping is either filled
with compressed air or air at atmospheric pres-
sure; the water enters the system through a con-
trol valve that is actuated either automatically
by a reduction of air pressure within the system
or by the manual activation of a remote control
located at each fire-hose station.

automatic elevator, self-service elevator
An elevator which starts and stops automati-
cally in response to the pushing of a button at
one of the landings or in the car.

automatic fire-alarm system A fire-alarm
system which detects the presence of a fire and
automatically initiates a signal indicating its
detection.

automatic fire detector An alarm-initiating
device that automatically detects heat, smoke,
or other products of combustion.

automatic fire door A fire door that auto-
matically closes a space when the temperature
within the space reaches a predetermined value,
or when there has been a significant increase in
the rate of temperature rise, smoke, or other
products of combustion within the space.

automatic fire-extinguishing system An

approved system of devices and equipment that
automatically detects a fire and then discharges
an approved fire-extinguishing agent onto or in
the area of the fire.

automatic fire pump A pump which pro-
vides the required water pressure in a fire
standpipe or sprinkler system; when the water
pressure in the system drops below a prese-
lected value, a sensor causes the pump to start,
and to stop the pump when the pressure is
restored.

automatic fire-suppression system An

engineered system using carbon dioxide (C0 2 ),
a foam wet or dry chemical, a halogenated extin-
guishing agent, or a clean extinguishing agent,
in an automatic sprinkler system to detect and
automatically suppress a fire through fixed pip-
ing and nozzles.

automatic fire vent l.A device installed in
the roof of a large single-story building which

automatic flushing system

operates automatically in the event of fire, provid-
ing an opening to the outdoors; removes smoke
and confines the fire so that it can be fought more
effectively. 2. See smoke and fire vent.

automatic flushing system A water tank
system which provides automatically for the
periodic flushing of urinals or other plumbing
fixtures, or of pipes having too small a slope to
drain effectively.

automatic gas shutoff device In a gas-fired
water heater, a device that shuts off the gas
supply if the water temperature in the heater
exceeds a predetermined limit.

automatic load shedding The automatic
disconnection of a part of the electrical load in a
building when there is an outage of the main
power supplied to the building; this action
reduces the total load placed on an emergency
power generator.

automatic operation In an elevator: an oper-
ation whereby the starting of the elevator car is
effected in response to the momentary actuation
of operating devices at the landing, and/or in
response to any automatic starting mechanism;
and whereby the car is stopped automatically at
the landings.

automatic operator A power-operated door-
activating device and control, actuated by
approaching traffic or a remote switch.

automatic pilot See safety shutoff device.

automatic smoke alarm system An alarm
system whose smoke detectors initiate and
transmit an alarm automatically.

automatic smoke vent See smoke and fire
vent.

automatic sprinkler A sprinkler head hav-
ing a nozzle which is normally closed, but opens
when exposed to a predetermined quantity of
heat — either by the melting of a fusible element
or by the rupturing of a liquid-filled glass bulb.

automatic sprinkler system 1. A fire-protec-
tion sprinkler system connected to a suitable
water supply; designed to provide an immediate
and continuous flow of water automatically in
case of fire. 2. A fire sprinkler system that reacts to
fire without the need for human intervention; a
type of automatic fire-protection sprinkler system.

automatic threshold closer Same as auto-
matic door bottom.

automatic transfer switch l.A combina-
tion of an electrically operated, double-throw
transfer switch and a control panel. Under nor-
mal circumstances, the connected load is ener-
gized from the utility source. Upon failure of this
source, the transfer switch automatically con-
nects the load to an emergency power generator
until power supplied by the utility is restored, at
which time it reconnects the load to the utility
source. 2. In an electric circuit, a switch which
automatically transfers a specific load from the
normal source to an emergency source if the for-
mer fails or if the voltage of the normal source
drops below a preset minimum.

automatic water supply A water supply sys-
tem whose operation is not dependent on any
manual setting of any items of equipment, such as
operating valves, starting pumps, or connectors.

automatic wet-pipe sprinkler system A
sprinkler system in which all piping and sprinkler
heads, at all times, are filled with water under
pressure; the system discharges immediately when
a sprinkler head operates, and the water contin-
ues to flow until the system is shut off.

auto-suppression system A British term for
a protection system that activates automatically
when a fire is detected; an automatic sprinkler
system.

aux Abbr. for "auxiliary."

auxiliary dead latch, auxiliary latch bolt,
deadlocking latch bolt, trigger bolt A

supplementary latch in a lock which automati-
cally deadlocks the main latch bolt when the
door is closed.
auxiliary energy subsystem An energy
source (other than the sun), used to supplement
or provide backup for the output provided by a
solar energy system.

auxiliary heat The additional heat which is

supplied by a conventional heating system in a
house when its solar energy system fails to
deliver sufficient energy to heat the house to a
comfortable temperature. See auxiliary energy
subsystem.

auxiliary heating fraction The ratio of aux-
iliary heat to the total heating requirements.

auxiliary loads All dynamic loads other than
the basic design loads which a building must
sustain.

awning blind

auxiliary rafter Above a principal rafter, a

second principal rafter, occasionally used in a
large queenpost truss.

auxiliary reinforcement In a prestressed
structural member, any reinforcement in addi-
tion to that whose function is prestressing.

auxiliary rim lock A secondary or extra lock
that is surface-mounted on a door to provide
additional security.

auxiliary rope-fastening device A device
attached to an elevator car, to a counterweight, or
to the overhead dead-end rope-hitch support;
automatically supports the car or counterweight
in case the fastening for the wire rope (cable) fails.

available short-circuit current The maxi-
mum electric current delivered by the electric
power system to a fault at a given point in a
circuit.

avalanche protector A barrier that prevents
loose material from sliding into the tracks or
wheels of any type of excavation or digging
machine.

avant-corps That part of a building which pro-
jects prominently from the main mass, e.g., a
pavilion.

AVE On drawings, abbr. for "avenue."

aventurine Glass (or glazes) containing col-
ored spangles of nonglassy material.

avenue l.A wide street, usually planted with
trees; generally straight. 2. A way of approach or
access.

average bond stress The force in a steel rein-
forcing bar divided by the product of its perime-
ter and its embedded length.

average concrete Concrete that is made with-
out artificial aggregates or admixtures; its strength
is not established by tests but is assumed to be the
value derived from its water-cement ratio.

average-end-area method A procedure for
calculating the volume of earthwork between
two cross sections; the cross-sectional areas are
averaged and multiplied by the distance
between cross sections to determine the volume.

average frequency of occurrence The

average number of years between storms that will
produce rainfall rates equaling or exceeding a
given amount; sometimes called the "return
period."

average grade Within a building construction
site, the arithmetic average of the elevations of
various ground surfaces within the site.

average haul The average distance that a
grading material is moved from cut to fill.

AVG On drawings, abbr. for "average."

avodire, white mahogany A west African
wood, pale yellow to white in color; soft to hard;
light in weight to moderately heavy; frequently
ribbon-striped. Used for interior finish, plywood,
and paneling.

AW Abbr. for "actual weight."

AAV Abbr. for "all-weather."

award A communication from an owner accept-
ing a bid or negotiated proposal. An award cre-
ates legal obligations between the parties.

A-weighted sound level The sound level
measured with a sound-level meter using A-
weighting, which alters the sensitivity of the sound-
level meter with respect to frequency so that the
sound-level meter is less sensitive at frequencies
where the ear is less sensitive; usually used in spec-
ifying permissible sound levels in buildings.

AWG On drawings, abbr. for American wire
gauge.

AWI Abbr. for "Architectural Woodwork
Institute."

awl A pointed tool used for piercing holes in
thin wood, hardboard, etc.

awning A roof-like covering of canvas, or the
like, often adjustable, over a window, door, etc., to
provide protection against the sun, rain, and wind.

awning blind A blind which is hinged at the
top; can swing outward and be fixed in position
by a stay.

awning blind

awning window

awning window A window consisting of a
number of top-hinged horizontal sashes one
above the other, the bottom edges of which
swing outward; operated by one control device.

INLET CONE OR
NLET BELL

awning window

AWPA Abbr. for "American Wood-Preservers'

Association."
AWS 1. Abbr. for "all wood screws." 2. Abbr. for

"American Welding Society."
A.W.W.I. Abbr. for "American Wood Window

Institute."
ax 1 . A sharp-edged steel tool for splitting wood,

hewing timber, etc. 2. An axhammer.

ax, 1

axed arch An arch which is constructed of bricks
that have been roughly cut into a wedge shape.

axed brick, rough-axed brick A brick,
shaped with an ax, that has not been trimmed;
when laid, the joints for such bricks are thicker
than those for gauged brick.

axed work (Brit.) A hand-dressed stone sur-
face showing toolmarks made by an ax, pick, or
bushhammer.

axhammer An ax for spalling or dressing rough
stone; has either one cutting edge and one ham-
mer face or two cutting edges.

axial- flow fan 1. One of the following types
of fans: vaneaxial, tubeaxial, or propeller. Such
fans impart energy to the air by giving it a
twisting motion. They are specified by blade
shape, ratio of hub-to-tip diameter, pitch of

MOTOR

HOUSING
CASING

axial-flow fan

the blades, and number of blades. Guide vanes
may be added to straighten the flow and
increase the efficiency. 2. See centrifugal fan.

axial force See axial load.

axial force diagram In statics, a graphical
representation of the axial load acting at each
section of a structural member, plotted to scale
and with proper sign as an ordinate at each point
of the member and along a reference line repre-
senting the length of the member.

axial load, axial force The resultant longitu-
dinal internal component of force which acts
perpendicular to the cross section of a structural
member and at its centroid, producing uniform
stress.

axis A straight line indicating center of symme-
try of a solid or plane figure.

axle pulley See sash pulley.

axle- steel reinforcing bar A reinforcing

bar fabricated from carbon-steel axles of rail-
road cars.

Axminster carpet A carpet having pile which
is attached to the carpet backing by inserting the
tufts by rows between the warp threads and then
binding them by means of the filling; this method
of carpet construction permits intricate design
and almost any number of colors to be used.

axonometric projection A form of ortho-
graphic projection in which a rectangular object,
projected on a plane, shows three faces. One of
two general divisions of pictorial projection (the
other being oblique projection); often divided into
three types: isometric, dimetric and trimetric.

azulejo

ayaka A type of pillar, placed on a platform
attached to a Buddhist stupa.

azimuth In plane surveying, a horizontal angle
measured clockwise from north meridian to the
direction of an object or fixed point.

azimuth traverse A survey traverse in which
the direction of the measured course is deter-
mined by azimuth and verified by back azimuth;
to initiate this type of traverse, it is necessary to
have a reference meridian.

azotea 1. In Hispanic architecture, a flat roof.
2. An open, elevated terrace, usually located at
the back of a house which it adjoins.

Aztec architecture The architecture of the
Aztecs in Mexico, succeeding the Mayans, from
the 14th cent, until the Spanish conquest in the
16th cent.

azulejo An earthenware tile of Spanish manu-
facture, painted and enameled in rich colors,
esp. one having a metallic luster.

nth

This page intentionally left blank

B Abbr. for beam.

B&B In the lumber industry, abbr. for "grade B
and better."

B&S l.On drawings, abbr. for "beams and
stringers." 2. On drawings, abbr. for "bell and
spigot." 3. On drawings, abbr. for Brown
and Sharpe gauge.

BIS 1 . Abbr. for "banded one side." 2. Abbr. for
"bead one side."

B2E Abbr. for "banded two ends."

B2S l.Abbr. for "banded two sides." 2. Abbr.
for "bead two sides." 3. Abbr. for "bright
two sides."

B2S1E Abbr. for "banded two sides and one end."

B3E Abbr. for "beveled on three edges."

B4E Abbr. for "beveled on four edges."

BA Abbr. for "bright annealed."

Babylonian architecture In ancient Baby-
lon, architecture characterized by: mud-brick
construction; walls articulated by pilasters and
recesses, sometimes faced with burnt and glazed
brick; narrow rooms, mostly covered with flat
timber and mud roofs; and the extensive use of
bitumen in drain and pavement construction
and as mortar.

back l.The rear, reverse, unseen, more remote,
or less important part of a structure, tool, or
object. 2. The support for a more prominent or
visible element; e.g., the back of wallboard is the
surface to be plastered. 3. The top or exposed
side of a slate, tile, or the like, in contrast to the
bed. 4. The ridge or top of a horizontal member
or structure like a joist, rafter, or roof. 5. A prin-
cipal rafter. 6. The extrados or top surface of an
arch, often buried in the surrounding masonry.
7. A low-grade veneer used for the back ply in
plywood construction. 8. The wainscoting below
the sash frame of a window, extending to the
floor.

back addition The projecting rear wing of
a house; an outrigger.

back arch Same as arriere-voussure.

backhand A piece of millwork used around a
rectangular window or door casing to cover the
gap between the casing and the wall or as a dec-
orative feature. Also called a backbend.

backhand

backbar A work surface behind (and at the
same height as) a liquor or service bar; usually
has cabinets under the work surface which are
used for storage, for the display of bottles and
glassware, or for refrigerated coolers.

back bedding See back putty.

backbend l.Same as backhand. 2. At the
outer edge of a metal door or window frame, the
face which returns to the wall surface.

backboard A temporary board on the outside
of a scaffold.

back boxing See back lining, 1.

back»brush To repaint a surface, which has
just been painted, with a return stroke.

back check In a hydraulic door closer, 1 a
mechanism which slows the speed with which
a door may be opened.

back choir Same as retrochoir.

back clip A special clip, 3 attached to the
back of a gypsum board; the clip fits into slots
in the framing that holds the gypsum board in
place.

backcloth Same as backdrop.

backcoating

backcoating A thin coating (such as sprayed
neoprene) on the back side of a fabric to
increase its durability, its resistance to the flow
of air, or its heat resistance.

back counter A work surface behind the front
serving counter of a restaurant, usually containing
short-order cooking equipment, storage cabinets,
storage shelves, etc.

back-draft damper A damper, 1 having blades
which are actuated by gravity, permitting air to
pass through them in one direction only.

backdrop On the theater stage, a large, taut,

flat canvas, usually hung from the grid at the rear

of the stage to mask the backstage area.
back edging Cutting a glazed ceramic pipe by

first chipping through the glaze around the

perimeter and then chipping the pipe below

until it is cut through.
backerboard See gypsum backerboard.
backer strip An asphalt-coated water-repellent

strip which is applied behind the joint where the

vertical edges of two shingles meet.
backfill Soil which is replaced in an area that

has been excavated previously.
back fillet The return of the margin of a groin,

doorjamb, or window jamb when it projects

beyond a wall.

back fillet A

backfill concrete A non-structural concrete
used to prepare a surface to receive structural
concrete, to fill excavated pockets in rocks, or to
correct over-excavation.

backfilling, backfill 1. Rough masonry built
behind a facing or between two faces. 2. Filling
over the extrados of an arch. 3. Brickwork in
spaces between structural timbers. Also see
nogging. 4. Soil or crushed stone used to fill the
space between the excavation or sheeting and

the exterior of a structure, or around the founda-
tion walls to provide means for water to drain
away from a foundation.

back flap, back fold, back shutter The leaf
in a window shutter that folds behind the exposed
leaf of the shutter; that part of a window shutter
that folds into a recess in the window casing.

backflap hinge, flap hinge A hinge having
a flat plate or strap which is screwed to the face
of a shutter or door.

backflow 1 . The flow of water or other liq-
uids, mixtures, or substances into the distrib-
uting pipes of a potable supply of water from
any other than its intended source. Also see
back siphonage. 2. Any flow in a direction
opposite to the natural or intended direction
of flow.

backflow connection Any arrangement of
pipes, plumbing fixtures, drains, etc., in which
backflow can occur.

backflow preventer A device used to prevent
water (or other liquids) from being siphoned into
a potable water system.

FLUSH-' DETAILS OF
CONNECTION SIPHON BHEAKER

backflow preventer for a hose connection

backflow valve See backwater valve.

back fold See backflap.

back form See top form.

background noise The total noise from all
sources other than a particular one of interest.

back gutter A gutter installed on the uphill
side of a chimney on a sloping roof; used to
divert water around the chimney.

back hearth, inner hearth That part of the
hearth, or floor, which is contained within the
jambs of the fireplace.

backhoe An excavating machine for cutting
trenches; a boom-mounted bucket moves
toward the machine, cutting the ground like a
hoe; then the machine turns away from the cut
to permit the operator to dump the soil.

back putty

[^iH-'TTW ^=^— BUCKET
"I I I DRAG CABLE

backhoe attachment on a crane

backhouse, back building l.A privy or
outhouse. 2. A structure that stands behind a
building to which it is a subsidiary.

backing See carpet backing.

backing board In a suspended acoustical ceil-
ing, a flat sheet of gypsum board to which acousti-
cal tile is attached by adhesive or mechanical
means.

backing brick A relatively low-quality brick
used behind face brick or other masonry.

backing coat A coat of plaster other than the
finish coat.

backing ring A backing in the form of a ring,
used during the welding of piping at butt joints.

backing up In masonry, the laying of backing
brick.

back jamb See back lining, 1 .

backjoint In masonry, a rabbet such as that
made on the inner side of a chimneypiece to
receive a slip.

back land Land having no road frontage require-
ment. It is surrounded by land owned by others.

backlighting The illumination of an object
from the rear.

back lining 1. A thin wood strip which lines a
window casing, next to the wall and opposite
the pulley stile, and provides a smooth surface
for the working of the weighted sash; also called
back boxing or a back jamb. 2. That piece of
framing forming the back recess for boxing
shutters.

back lintel A lintel which supports the backing
of a masonry wall, as opposed to the lintel sup-
porting the facing material.

back»mop To mop the back or underside of
roofing felts with asphalt or tar when laying a
built-up roof.

back mortaring Same as backplastering and
pargetting, 3.

back-nailing Nailing the plies of a built-up
roof to the substrate (in addition to hot mopping)
to prevent slippage.

back nut l.A threaded nut, one side of
which is dished to retain a grommet; used in
forming a watertight pipe joint. 2. A locking
nut on the shank of a pipe fitting, tap, or
valve.

back observation Same as backsight.

back-paint To paint the reverse or hidden side
of an object, usually for protection against the
weather.

backplastering A coat of plaster applied to
the back side of lath, opposite the finished sur-
face.

backplate A plate, usually metal or wood,
which serves as a backing for a structural
member.

backplate lamp holder A lamp holder, inte-
grally mounted on a plate, which is designed for
screwing to a flat surface.

back pressure Pressure developed in opposi-
tion to the flow of liquid or gas in a pipe, duct,
conduit, etc.; due to friction, gravity, or some
other restriction to flow of the conveyed fluid.

back-pressure valve See check valve.

back propping The placing of timbers, usually
set in a diagonal or oblique position, to hold a
wall in place.

back putty, bed glazing The bedding of
glazing compound which is placed between
the face of glass and the frame or sash con-
taining it.

back putty

backsaw

backsaw A saw having a metal strip along its
back to stiffen it; has many small teeth for fine,
accurate sawing, as for miters.

backsaw

backset l.The horizontal distance from the
face of a lock or latch to the center of the key-
hole, knob, or lock cylinder. 2. Same as set-
back.

back shore In raking shores, an outer member
under a rider shore that temporarily supports the
side of a building.

back shutter See backflap.

backsight In surveying, a sight on a previously
established survey point or line.

back siphonage The flowing back of used,
contaminated, or polluted water from a plumb-
ing fixture or vessel into the pipe which feeds it;
due to reduced pressure in the pipe.

back siphonage preventer See vacuum
breaker.

backsplash A protective panel on the wall
behind a sink or counter; an apron, 7.

backstage The entire area behind the fire wall
of the stage of a theater, including the rear of the
stage, storage areas, and dressing rooms.

backstay Same as brace, 1.

back-to-back house A house with a party
wall at the rear as well as along the sides.

backup l.That part of a masonry wall behind
the exterior facing. 2. A compressible material
used behind a sealant to reduce its depth and to
support the sealant against sag or indentation. 3.
Overflow in a drain or piping system, due to
stoppage. 4. A condition where waste water
flows back into another fixture or compartment
or water line (but does not flow back into the
potable water system).

backup protection In an electrical system, a
type of protection initiated by a sensing device
that detects a failure of a protective element
(such as a circuit breaker); in that event, the
next upstream protective device takes over the
protective function.

backup rod A strip of plastic foam that is
inserted in a joint to limit the penetration of
sealant into the joint.

backup strip A piece of wood at the corner of
a ceiling and side wall; serves as the mounting
for the ends of the gypsum-board panels.

backup strip, lathing board A wood strip
which is fixed at the corner of a partition or wall
to provide a nailing surface for ends of lath.

back veneer In veneer plywood, the layer of
veneer on the side of a plywood sheet which is
opposite the face veneer — usually of lower
quality.

back '

back vent An individual vent for a plumbing
fixture located on the downstream (sewer) side
of a trap, 1 to protect the trap against siphonage.

b<xk vent-

back vent

backwater valve, backflow valve A type
of check valve in a drainage pipe; reversal of
flow causes the valve to close, thereby cutting off
flow.

bacterial corrosion A corrosion which results
from substances (e.g., ammonia or sulfuric acid)
produced by the activity of certain bacteria.

badger 1. A tool used inside a pipe or culvert to
remove excess mortar or deposits. 2. A badger
plane.

bake house

backwater valve

IALKI .flUKVIThB

8MI PtOATIH
NOfflMAL PMITign

OKAINPIPE

backwater valve: installation

badger plane A hand plane, the mouth of
which is cut obliquely from side to side, so that it
can work close up to a corner.

badigeon A filler or patching material used in
masonry or wood work.

baffle 1. A plate used to control the flow of a liq-
uid. 2. An opaque or translucent plate used to
shield a light source from direct view at certain
angles; a light baffle. 3. A flat deflector or obstruc-
tion designed to reduce sound transmission. 4. A
plate that retards and/or changes the direction of
the flow of air, air-gas mixtures, or flue gases.

bag, sack A quantity of portland cement: 94 lb
in the United States, 87.5 lb in Canada, 112 lb
(50.8 kg) in the United Kingdom, and 50 kg in
most countries using the metric system.

bagasse A by-product of sugar cane after the
juice has been extracted; used as a fuel and also
as the principal component in cellulose-cane
acoustical tile.

bagged brickwork Brickwork that is prepared
for painting by applying a thin mixture of water
and mortar to the brickwork, such as by pound-
ing the brickwork with a burlap (Hessian) bag
containing the mixture.

bag molding The application of pressure on a
material during molding so that it takes the shape
of a curved, rigid die. The material, contained
within the die and a flexible cover, is deformed by
changes of pressure within the enclosure.

bagnette A bead molding.

bagnio 1. A bathing establishment. 2. A brothel.
3. A Turkish prison.

bag plug An inflatable drain stopper; when
inflated, it acts to seal a pipe; usually located at
the lowest point of the piping system.

bag-rubbed joint Same as flush-cut joint.

bag trap An S-shaped trap, 1 in which the ver-
tical inlet and outlet pipes are in alignment.

bag trap

bague An annular molding encircling the shaft
of a column or pillar, either half-way between
the base and capital or at lesser intervals.

baguette A small, convex molding.

bahut l.In a masonry wall or parapet, the
rounded upper course. 2. A low wall surmount-
ing a cornice to carry the roof structure.

baignoire A box in a theater in the lowest
tier.

bail 1 . The wall of an outer court of a feudal cas-
tle. 2. A hinged loop that is used for lifting.

bailey The open area within a castle fortifica-
tion. See inner bailey and outer bailey; also see
motte-and-bailey.

bajarreque A wattle-and-daub wall constructed
of bagasse, which is covered with plaster mixed
with clay and straw.

baked finish A surface coating that achieves
the desired properties by being baked, usually at
a temperature of at least 150°F (65°C).

bake house A small subsidiary structure
having one or more ovens used exclusively for

bake oven

baking of bread and pastries; once especially
found in religious communities and on planta-
tions; usually located away from the principal
dwelling to reduce the risk of setting it on
fire.
bake oven An oven constructed of bricks, usu-
ally having a circular or oval dome; often located
within the hearth of the principal fireplace of a
colonial home, usually in a corner of the hearth
and a few feet above it. Bake ovens were once an
integral part of the fireplace construction; some
were heated by glowing charcoal or embers that
were swept out before the unbaked loaves were
inserted and the iron oven door closed. Also
called a beehive oven, bread oven, brick oven,
or Dutch oven.

bake oven (longitudinal section)

baking, sto ving The use of heat on fresh paint
films to speed the evaporation of thinners and to
promote the reaction of binder components so as
to form a hard polymeric film.

balance arm On a projected window, a side
supporting arm which is constructed so that the
center of gravity of the sash is not changed
appreciably when opened.

balance beam, balance bar A long beam,
attached to a gate (or drawbridge, etc.) so as to
counterbalance the weight of the gate during
opening or closing.

balanced circuit A three-wire electric circuit
in which the load is the same on each side of the
neutral wire.

balanced construction A plywood or sand-
wich-panel construction which has an odd
number of plies laminated together so that the

construction is identical on both sides of a plane
through the center of the panel.

balanced door A door so arranged that it is
held either open or closed by weights.

balanced earthwork Cut and fill work in

which the amount of fill equals the amount of
material excavated.
balanced failure condition The condition
that exists when there is the simultaneous
occurrence of a primary compression failure
and a primary tension failure.

balanced ladder A ladder held in a vertical
position by guides with a weight attached equal
to the weight of the ladder.

balanced load 1. A load connected to an elec-
tric circuit (as a three-wire system) so that the
currents taken from each side of the system are
equal and the power factors are equal. 2. The
load at which there is simultaneous crushing of
concrete and yielding of tension steel.

balanced reinforcement An amount and
distribution of steel reinforcement in a flexural
reinforced concrete member such that the al-
lowable tensile stress in the steel and the allow-
able compressive stress in the concrete are
attained simultaneously.

balanced sash In a double-hung window, a
sash which opens by being raised or lowered and
whose weight is balanced with counterweights
or with pretensioned springs so that little force is
required to lift the sash.

balanced step, dancing step, dancing
■winder One of a series of winders arranged so
that the width of each winder tread (at the nar-
row end) is almost equal to the tread width in
the straight portion of the adjacent stair flight.

balance pipe A pipe connection used to
equalize the pressure at two points in a piping
system.

balancing A procedure for adjusting the mass
distribution of a rotor so that vibration of the jour-
nals, or the forces on the bearings, are reduced or
controlled.

balancing plug cock See balancing valve.

balancing valve, balancing plug cock A
valve used in a pipe for controlling fluid flow;
not usually used to shut off the flow.

balaneion A Greek term for a bath.

ballast

balaustre, canary wood A South American

glossy wood; quite hard, heavy; yellowish brown,

orange, or purplish brown in color.
BALC On drawings, abbr. for balcony.
balconet A pseudo-balcony; a low ornamental

railing to a window, projecting but slightly

beyond the threshold or sill.

balconet

balcony 1. A projecting platform on a building,
sometimes supported from below, sometimes can-
tilevered; enclosed with a railing or balustrade. 2.
A projecting gallery in an auditorium; a seating
area over the main floor. 3. An elevated platform
used in a permanent stage setting in a theater.

balcony outlet In a vertical rainwater pipe
that passes through an exterior balcony, a fitting
which provides an inlet for the drainage of rain-
water from the balcony.

balcony rail See rail, 2.

balcony stage A balcony used as a playing
area, as in the Elizabethan theater.

baldachin, baldacchino, baldachino, bal-
daquin, ciborium An ornamental canopy
over an altar, usually supported on columns, or a
similar form over a tomb or throne.

bald roof See smooth-surfaced roof.
balection molding See bolection molding.

bale house l.See straw bale house. 2. An

obsolete term for warehouse.

bale tack Same as lead tack.

balistraria In medieval battlements, a cross-
shaped aperture through which crossbowmen
shot arrows.

balk, baulk 1. A squared timber used in build-
ing construction. 2. A low ridge of earth that
marks a boundary line.

baldachin

balk tie A balk, 1 which joins the wall posts of a
timber roof, preventing the walls from spreading.
ball and flower See ballflower.

ballast 1. Coarse stone, gravel, slag, etc., used as
an underlay er for poured concrete. 2. A device
used to provide the required starting voltage and

ballast factor

operating current for fluorescent, mercury, or
other electric-discharge lamps. 3. Class P: A bal-
last for a fluorescent lamp which meets the
requirements of the Underwriters' Laboratories,
Inc.; includes an automatic resetting thermal
protector to remove the ballast from the circuit
if its temperature exceeds a specified value. 4.
Same as constant-wattage ballast.

ballast factor The ratio of the luminous output
of a lamp when operated on a ballast to its lumi-
nous output when operated under standardized
rating conditions.

ballast noise rating A measure of the noise
generated by a fluorescent lamp ballast; desig-
nated by letters from A (the quietest) through F
(the noisiest).

ball-bearing hinge A hinge which is equipped
with ball bearings between the hinge knuckles in
order to reduce friction.

ball breaker Same as wrecking ball.

ball catch A door fastener having a contained
metal ball which is under pressure from a spring;
the ball engages a striking plate and keeps the
door from opening until force is applied.

ball-check valve A spring-operated check
valve in a piping system; when the fluid flows in
one direction, pressure against a movable ball
allows fluid to pass; when the direction of flow is
reversed, the ball is forced against a seat, thereby
stopping the flow.

ball cock A float valve with a spherical float.

balled and burlapped In landscape architec-
ture, a method of preparing a plant or tree for
transplantation; the largest part of the root sys-
tem is covered with a ball of soil and then
wrapped in burlap (Hessian) for protection and
ease of handling when it is moved to the site
where it is to be planted.

ball float A floating device, usually approx.
spherical in shape, which is used to operate a
ball valve.

ballflower A spherical ornament composed of
three conventionalized petals enclosing a ball,

jaglr-j

W^ft*a

Mum '^hhI

usually in a hollow molding, popular in the Eng-
lish Decorated style.

balling up In welding, the formation of globules
of molten brazing filler metal or flux as a result of
failure to wet adequately the metal being welded.

ballium The court of open space within a
medieval fortification; a bailey.

ball joint A joint in which one part has a ball-
shaped end that is held in a spherical shell
attached to the other, thereby permitting the
axis of one part to be set at any angle with
respect to the other.

balloon A globe or round ball, placed on the
top of a pillar, pediment, pier, or the like, which
serves as a crown, 1.

balloon framing, balloon frame A system of
framing a wooden building; all vertical structural
elements of the exterior bearing walls and
partitions consist of single studs which extend the
full height of the frame, from the top of the sole-
plate to the roof plate; all floor joists are fastened
by nails to studs. Compare with braced framing.

ballflower

balloon framing

balloon-payment loan A type of loan agree-
ment, whether or not secured by a mortgage, in
which the final payment due at maturity is much
larger in amount than each of the periodic pay-
ments required during the life of the loan.

ball peen hammer A hammer having a hemi-
spherical peen.

baluster column

ball peen hammer

ball-penetration test An ASTM test method
used as a measure of the consistency of concrete;
a metal weight having a hemispherically shaped
bottom is placed on the smooth level surface of
the concrete, and the depth to which it sinks is
measured.

ballroom A large social hall expressly designed
for dancing, but frequently used for dining or
large meetings.

ball test 1. See Kelly ball test. 2. In a drain, a
test for freedom from obstruction and for circu-
larity; a ball (less than the diameter of the drain
by a specified amount) is rolled through the
drain.

ball valve A valve for regulating the flow of
fluids by a movable ball which fits in a spherical
seat.

balteus 1 . The band in the middle of the bolster
of an Ionic capital. 2. The band joining the
volutes of an Ionic capital. 3. One of the pas-
sages dividing the auditorium of ancient Roman
theaters and amphitheaters horizontally into
upper and lower zones.

baluster, banister 1 . One of a number of short
vertical members, often circular in section, used
to support a stair handrail or a coping. 2. {pi.) A
balustrade. 3. The roll forming the side of an
Ionic capital; a bolster, pulvinus.

baluster, 1

Body

ball valve

balnea, pi. of balneum Roman baths, usually
the great public ones.

balnearium In ancient Rome, a private bath-
room.

balsa, corkwood The lightest of all woods,
with density of about 7 to 10 lb per cu ft ( 1 10 to
160 kg per cu m); used for the core of light-
weight sandwich panels, models, etc.

baluster, 3

baluster column 1 . A column shaped some-
what like a baluster, with a short, massive shaft.
2. A short, thick-set column in a subordinate
position, as in the windows of early Italian
campanili.

baluster column

baluster shaft

baluster shaft Same as baluster column.

baluster side On an Ionic capital, the return
face (having the form of a concave roll), reach-
ing from volute to volute.

baluster side

balustrade An entire railing system (as along
the edge of a balcony) including a top rail and its
balusters, and sometimes a bottom rail.

TOP RAIL

BALUSTER

BOTTOM

RAIL

balustrade

balustrum Same as altar rail.

bamli In the architecture of India, a court or

courtyard.
banana oil See amyl acetate.

banco In Spanish architecture and its deriva-
tives, a built-in seat.

band l.Any horizontal flat member or molding
or group of moldings projecting slightly from a
wall plane and usually marking a division in the
wall. Also called band molding or band course.

band, 2

2. A small, flat molding, broad, but of small projec-
tion, rectangular or slightly convex in profile, used
to decorate a surface either as a continuous strip or
formed into various shapes. Also called fillet, list.

3. A fascia on the architrave of an entablature.
bandage A strap, band, ring, or chain placed

around a structure to secure and hold its parts
together, as around the springing of a dome.

band clamp A two-piece metal clamp, secured
by bolts at both ends; used to hold riser pipes.

band course Same as belt course.

banded architrave In late neoclassic architec-
ture in England, Italy, and France, an architrave,
2 interrupted at intervals by smooth projecting
blocks, between which are set the molded por-
tions of the architrave.

banded barrel vault A masonry barrel vault
whose semicircular cross section is stiffened at
regular intervals by arches which project
beneath the vault's surface.

banded column A column with drums that
alternate in size, color, or degree of ornamentation.

banded column

banded impost In medieval architecture, an
impost with horizontal moldings, the section of
the molding of the arch above being similar to
that of the shaft below.

bank barn

banded impost

banded pilaster A pilaster decorated in the
manner of a banded column.

banded rustication Courses of masonry, alter-
nating smooth ashlar with rustication, in
Renaissance architecture and derivatives.

banded surround A surround (i.e., a decora-
tive architectural element around a doorway,
fireplace, or window) that is banded, usually by
adjacent masonry blocks that are of two different
sizes; for example, see Gibbs surround.

bandelet 1 . An annulet. 2. A small flat molding.

banderol, banderole, bannerol A decora-
tive representation of a ribbon or long scroll,
often bearing an emblem or inscription.

banderol

banding 1 . Wood edging for veneered doors or
panels; normally used at the edge of plywood or
coreboard constructions. 2. One or more deco-
rative wood strips; decorative inlay. 3. Metal,
plastic, or fiber straps to tie bundles together. 4.
The strapping of the top of a timber pile to pre-
vent its splitting while being driven.

banding plane A carpenter's plane used to cut
grooves and to inlay strings and bands in straight
and circular work.

band iron A thin metal strap used as a form tie,

a hanger, etc.
bandlet Same as bandelet,
band molding A band, 1.

band saw A saw consisting of an endless,
toothed steel belt which runs between two
wheels, one of which is machine-powered.

band shell A sound-reflective construction,
usually in the open air, to direct sound from per-
formers on a stage to an audience.

band window One of a horizontal series of
three windows or more, separated only by mul-
lions, that form a horizontal band across the
facade of a building; for example, see frieze-band
window. Most commonly found in buildings
erected after 1900. Also called a ribbon window.

banister l.A handrail for a staircase. 2. A
baluster.

bank 1 . A mass of soil rising above a digging
level. 2. An establishment which receives,
lends, and exchanges money and carries out
other financial transactions.

bank barn A two-story barn usually built into
the slope of a hill and oriented so that the ground
floor is protected from the prevailing wind. An
inclined driveway leads to a large sliding door on
the upper floor, which contains an area set aside
for threshing grain, storing grain, and storing ani-
mal feed. The level below provides housing for
animals and is entered at ground level from an
enclosed yard. In the United States, sometimes
called a German barn, Pennsylvania barn, or
Pennsylvania Dutch barn. Also see barn, forebay
barn, Swiss barn, Yankee barn.

bank barn

bank cubic yard

bank cubic yard (or meter) A unit to express
the volume of bank material.

bank depository A safe on the exterior of a
building which receives deposits after business
hours.

banker The bench or table upon which brick-
layers and stonemasons prepare and shape their
material.

banker»mark In medieval construction, a mark
cut in a dressed stone to identify the stonecutter.

banker mason Same as master mason.

bank gravel See bank-run gravel.

bank house See German Colonial architecture.

bank material Soil or rock in place before
excavation or blasting.

bank measure 1. A measure of the volume of a
mass of soil or rock, before excavation, in its nat-
ural position. 2. The measurement of earth mate-
rial in situ (i.e., in its original place in the ground).

bank meters The number of cubic meters of
material in its original place in the ground.

bank-run gravel, bank gravel, run-of-bank
gravel Aggregate taken directly from natural
deposits; contains both large and small stones.

bank sand Compared to lake sand, a sand having
sharp edges so that when used in plastering it
results in a better bond and greater plaster strength.

bank yards The number of cubic yards of
material in its original place in the ground.

bannerol See banderol.

banner vane A weather vane having the
shape of a banner; balanced by a weight on the
other side of the banner.

banquet hall A room used for dining, social
gatherings, or meetings accommodating large
numbers of people.

banquette 1. A long, upholstered seat built in
against a wall. 2. A raised, narrow walk along a
roadway. 3. A term once used in some parts of
the American South for a sidewalk. 5. Same as
barbette.

banquette cottage In New Orleans in the
early 19th century, a small town house located
flush against a sidewalk.

baptistery A building or part of one wherein
the sacrament of baptism is administered.

bar 1. One of the thin strips of wood or metal
forming the several divisions of a sash or a

banner vane

baptistery

bargeboard

bar, 1

wood panel door, employed to receive the glass.
2. A solid metal product having a square, rec-
tangular, or other simple symmetrical cross-
sectional shape and a length much greater than
its width. 3. A counter over which liquor and
other beverages are served; may be equipped
with a footrail if stools are not provided. 4. A
steel reinforcing bar. 5. A unit of pressure equal
to 10 5 pascals, 10 5 newtons per square meter, or
10 6 dynes per square centimeter. 6. One of a
number of thin strips of wood or metal forming
the several divisions of a window sash or a
wood-paneled door. 7. Same as iron mantel, 3.

baraban In early Russian architecture, same as
drum, 2.

barbacan See barbican.

barabara 1. A sod house. 2. A partially under-
ground dwelling.

barb bolt, rag bolt A bolt having jagged edges
to prevent its being withdrawn from the object
into which it is driven.

barbed Said of a shank (e.g., that of a nail)
which has been provided with repetitive ridges
or indentations which may be shallow or deep,
oblique or crosswise, diagonal or perpendicular.

barbed wire, barbwire Two or more wires
twisted together with sharp hooks or points (or a
single wire furnished with barbs); used for fences.

bar bender Same as hickey.

bar bending In reinforced concrete construc-
tion, the process of bending reinforcing bars to
various shapes.

barbette A raised platform in a medieval fort
that served as a mounting surface for a weapon
to fire over a parapet at the enemy.

barbican, barbacan The outer defense work of a
castle or town, frequently a watchtower at the gate.

barbican

barbwire See barbed wire.
bar chair See bar support.

bar clamp A clamping device used in carpen-
try; consists of a long bar with adjustable clamp-
ing jaws.

bar clamp

bare Descriptive of a piece of material which
is smaller than the specified dimensions; scant.

bare conductor An electrical conductor hav-
ing no covering or electrical insulation.

barefaced tenon, bareface tenon A tenon

having a shoulder cut on one side only.

bargain and sale deed A deed in which the
grantor represents that he has some interest in
the property being conveyed, without warrant-
ing that he has a clear unencumbered title.
Such a deed often includes a warranty that the
grantor did not encumber the property or con-
vey away any part of the title during his period
of ownership. Also see quitclaim deed; warranty
deed.

barge arch A low arch of a bridge under which
barges are transported.

bargeboard, gableboard, vergeboard A
board which hangs from the projecting end of a

barge couple

bargeboard

roof, covering the gables; often elaborately
carved and ornamented in the Middle Ages.

barge couple l.One of the two rafters that
support that part of a gable roof which projects
beyond the gable wall. 2. One of the rafters
(under the barge course) which serve as grounds
for the barge boards and carry the plastering or
boarding of the soffits; also called a barge rafter.

barge course l.The coping of a wall, formed
by a course of bricks set on edge. 2. In a tiled
roof, the part of the tiling which projects beyond
the principal rafters (bargeboards) where there is
a gable.

barge rafter Same as barge couple, 2.

barge spike, boat spike A long spike, square
in cross section, used in timber construction.

barge stone One of the stones, generally pro-
jecting, which form the sloping top of a gable
built of masonry.

bar iron A strong, malleable iron, available in
the form of bars, which can be beaten into vari-
ous shapes by blacksmiths to form tools, horse-
shoes, hardware, and highly decorative ironwork.
See wrought iron.

barite A mineral used in concrete as an aggre-
gate, esp. for the construction of high-density
radiation shielding; also called barium sulfate.

barium plaster A special mill-mixed gypsum
plaster containing barium salts; used to plaster
walls of x-ray rooms.

barium sulfate See barite.

bar joist An open-web flat-trussed structural
member used to support a floor or roof structure.

bark The protective outer layer of a tree, com-
posed of inner, conductive cells and outer cork-
like tissue.

bark house A dwelling once used by certain

Indian tribes in America; usually made of a

framework of wood poles, lashed together, and

covered with overlapping slabs of bark.
bark mill A small building that was once used

for processing bark used in dyeing and tanning.
bark pocket, inbark, ingrown bark A

small quantity of bark, nearly or entirely enclosed

in wood.
barley-sugar column (Brit.) A spiral column.
bar mat A network of steel reinforcing bars

assembled in two or more layers and welded or

tied together.
barmkin In the Middle Ages, the battlement

of a fortified tower in Scotland and northern

England.
bar molding A rabbeted molding applied to

the edge of a counter or bar to serve as a nosing.

bar molding

barn A farm building, most often rectangular
(but occasionally circular or polygonal), for hous-
ing farm animals, storing farm equipment, thresh-
ing grain, and storing grain, hay, and other
agricultural produce. Barn construction usually
depends on such factors as the local climate and
traditions, building materials available, the skills
and time required for construction, and the cost.
For some examples, see bank barn, basement
barn, circular barn, connected barn, Connecticut
barn, crib barn, double barn, Dutch barn, English
barn, forebay barn, four-crib barn, German barn,
hex barn, New England connected barn, octagon
barn, Pennsylvania barn, Pennsylvania Dutch
barn, potato barn, raised barn, round barn, side-
hill barn, Sweitzer barn, Swiss barn, three-bay
barn, tobacco barn, Yankee barn.

barn-door hanger A hanger for an exterior
sliding door; consists of a frame which moves
along a horizontal track, supported by rollers.

barricade

barn-door stay A small wheel which rolls
along a horizontal track and guides the move-
ment of a barn door.

barn raising In the United States before the
20th century, a cooperative effort in which the
elements of the framework for a large barn
were assembled and lifted into place. The walls
were supported by sections of a massive timber
framework, called bent frames. First, the cellar
was dug and the barn floor constructed. Next,
the bent frames were assembled on the ground
adjacent to the barn by fitting the various com-
ponents of the frame together and fastening
them with wood pegs driven into previously
drilled holes. Finally, at the appropriate loca-
tions, each bent frame was raised into an upright
position by the use of long poles with steel points
(barn pikes) and then interconnected with other
bent frames. See the illustration under bent
frame showing how the bent frames were raised,
an action that required considerable manpower
and therefore the assistance of neighbors; this
collaborative effort is also known as a barn raising
or raising bee.

barometric damper An automatic adjustable
device for regulating the draft through a fuel-
burning appliance, thereby making operation of
the appliance nearly independent of the chim-
ney draft over its normal range of operation.

barometric draft regulator A damper usu-
ally installed in the breeching between a boiler
and chimney; permits air to enter the breech-
ing automatically as required, to maintain a
constant overfire draft in the combustion
chamber.

barometric pressure See atmospheric pressure.

Baroque A European style of architecture and
decoration which developed in the 17th cent, in
Italy from late Renaissance and Mannerist
forms, and culminated in the churches, monas-
teries, and palaces of southern Germany and
Austria in the early 18th cent. It is characterized
by interpenetration of oval spaces, curved sur-
faces, and conspicuous use of decoration, sculp-
ture, and color. Its late phase is called Rococo.
The style prevailing in the restrained architec-
tural climate of England and France can be
called Baroque classicism.

bar post One of the posts driven into the ground
to form the sides of a field gate.

barracks Permanent or temporary housing for
soldiers or, less often, groups of workmen.

bar-rail molding Same as bar molding.

barreaux Wood bars forming a latticework
between wall posts in French Vernacular archi-
tecture of Louisiana and environs; provided a
structural support for infilling set between struc-
tural timbers.

barred-and-braced gate A gate with a diago-
nal brace to reinforce the horizontal timbers.

barred gate A gate with one or more horizon-
tal timber rails.

barrel 1 . A weight measure for portland cement
in the US, corresponding to 376 pounds net; this
measure is now obsolete. 2. (VS) A vessel which
holds 3 1 Vi gal of liquid. 3. That portion of a pipe
having a constant bore and wall thickness.

barrel arch An arch formed of a curved solid
plate or slab, as contrasted with one formed with
individual curved members or ribs.

barrel bolt, tower bolt A door bolt which
moves in a cylindrical casing; not driven by
a key.

barrel ceiling A ceiling of semicylindrical shape.

barrel drain Any drain which is cylindrical in
shape.

barrel fitting A short length of threaded con-
necting pipe, as a nipple.

barreling, tumbling The application of paint
to small articles by tumbling them in a barrel
containing paint.

barrel nipple A barrel fitting threaded at each
end.

barrel roof, barrel shell roof l.A roof of
semicylindrical section; capable of spanning
long distances parallel to the axis of the cylinder.
2. A barrel vault.

barrel shell A reinforced concrete scalloped
roof that spans a structure in one direction as
folded-plate construction, and in the other
direction as a barrel vault.

barrel vault, barrel roof, cradle vault, tun-
nel vault, wagonhead vault, wagon
vault A masonry vault of plain, semicircular
cross section, supported by parallel walls or
arcades and adapted to longitudinal areas.

barricade An obstruction to deter the passage
of persons or vehicles.

barrier

3Bniiy,

haiauft

sprmg

barrel vault

barrier 1. Same as barricade. 2. According
to the Architectural Barriers Act, any obstacle to
the accessibility of a building by disabled people.

barrier fort 1. One of a number of mutually-
supporting medieval forts which protect a large
area of the countryside. 2. A fort that can with-
stand a limited siege.

barrier-free Said of a building or facility that is
accessible to the handicapped.

barrier-free environment As specified in

the Americans with Disabilities Act, an environ-
ment containing no barriers, 2.

barrow l.A wheelbarrow. 2. An elongated
artificial mound protecting a prehistoric cham-
ber tomb or passage grave.

barrow area An area that serves as a source of
fill, providing soil which is used to raise an exist-
ing grade elsewhere.

barrow hole A hole that is left open in an
exterior wall during a building's construction to
provide access to the interior. Upon completion
of construction, the hole is closed up.

barrow run A temporary pathway of wood
planks or sheets to provide a smooth access for
wheeled materials-handling carriers on a build-
ing site.

Barryesque A variation of the Italianate style

introduced by Sir Charles Barry, an outstanding
Victorian architect who designed the Houses of
Parliament.

bar sash lift A type of handle, attached to the
bottom rail of a sash, for raising or lowering it.

bar schedule A tabulation of the reinforce-
ment used in reinforced concrete, showing the

number, shape, size, and dimensions of each ele-
ment that is required.

bar screen A coarse screening device used to
separate large pieces of stone from smaller
pieces, which fall through the spaces between
equally spaced bars, 2.

bar size section A hot-rolled angle, channel,
tee, or zee having its greatest cross-sectional
dimension less than 3 in. (7.6 cm).

bar spacing The center-to-center distance (per-
pendicular to the longitudinal axis) between par-
allel reinforcing bars.

barstone Before the invention of grates in a
fireplace, one of two upright stones placed in the
fireplace to receive the ends of a metal bar on
which meat was roasted.

bar strainer A screening device consisting of a
bar or a number of parallel bars; used to prevent
objects from entering a drain; also see bar
screen.

bar support, bar chair A device used to support
and/or hold steel reinforcing bars in proper posi-
tion before or during the placement of concrete.

bartisan Same as bartizan.

bartizan On a fortified wall, a small overhang-
ing structure with lookout holes and loops, often
at a corner or near an entrance gateway.

bartizan

bar tracery A pattern formed by interlocking
bars of stone within the arch of a Gothic window.

bar-type grating An open grid assembly of
metal bars in which the bearing bars (running in
one direction) are spaced by rigid attachment to
cross bars.

barway A gate opened by moving a bar or bars.

barytes Same as barite.

baseboard radiator unit

bar tracery

basalt A dark, fine-grained, igneous rock used
extensively for paving stones, but rarely for
building stone.

bascule A structure that moves about a hori-
zontal axis, as a seesaw, with a counterbalance at
one end.

base l.The lowest (and often widest) visible
part of a building, often distinctively treated.
A base is distinguished from a foundation or
footing in being visible rather than buried. 2.
A low, thickened section of a wall; a wall base.
Also see socle. 3. Lower part of a column or
pier, wider than the shaft, and resting on a
plinth, pedestal, podium, or stylobate. Also see
Asiatic base, Attic base. 4. A baseboard; skirt-
ing. 5. A preparation for a finished surface, as
for flooring, stucco, paint, etc.; a surface to
which the base coat of plaster is applied. Also
see backing, ground. 6. In paint, either the
medium or the main chemical ingredient. 7. In
asphaltic or portland cement concrete paving,
the prepared bottom course of crushed stone or
gravel upon which subsequent courses are laid;
serves to distribute localized wheel loads over a
larger subbase and hence to improve load-
bearing capacity. 8. The lowest point of any
vertical pipe.

UlUUUU

TUSCAN HOMfiN DORIC

bases, 3

base anchor The metal piece attached to the
base of a doorframe for the purpose of securing
the frame to the floor; either fixed or adjustable.

basebead Same as base screed.

base bid The amount of money stated in the
bid as the sum for which the bidder offers to per-
form the work, 1 not including that work for
which alternate bids are also submitted.

base bid specifications The specifications
listing or describing only those materials,
equipment, and methods of construction upon
which the base bid must be predicated, exclu-
sive of any alternate bids. Also see specifica-
tions and closed specifications.

base block 1 . A block of any material, generally
with little or no ornament, forming the lowest
member of a base, or itself fulfilling the functions
of a base, as a member applied to the foot of a
door or to window trim. 2. A rectangular block at
the base of a casing or column which the base-
board abuts; usually slightly thicker than either
the casing or baseboard. 3. A skirting block.

baseboard, mopboard, scrubboard, skirt-
ing board, washboard A flat projection
from an interior wall or partition at the floor,
covering the joint between the floor and wall
and protecting the wall from kicking, mopping,
etc. It may be plain or molded; a base, 4.

baseboard

baseboard heater A heating system in which
the heating elements are installed in panels
along the baseboard of a wall.

baseboard raceway A channel having a
removable cover, sometimes installed along a
baseboard in an existing building to house
wiring. Removal of the cover provides easy
access to the wiring.

baseboard radiator unit A heating unit which
is designed to replace a baseboard along a wall;
water or steam flows directly behind the face of

base building

Fins

Tube

baseboard radiator unit

the unit (or heat is supplied to the face by electric
heating elements directly behind it); heat from
the face is transmitted to the room. In the finned-
tube type, the fins are heated by water or steam
flowing through the tube; this heat is delivered to
the room through slots in the face of the unit.
base building A building for general usage
which has not yet been adapted to meet the spe-
cial requirements of a specific tenant.

base cap See base molding.
base clip Same as base anchor.

base coat 1. All plaster applied before the fin-
ish coat; may be a single coat or a scratch coat
and a brown coat. 2. The first coat applied to a
surface, as paint; a prime coat. 3. An initial coat
applied to a wood surface before staining or oth-
erwise finishing it.

base coat floating The spreading, compact-
ing, and smoothing of the base coat of plaster so
that it is finished to a reasonably true plane.

base course 1. A foundation or footing course,
as the lowest course in a masonry wall. 2. A layer
of selected material of planned thickness, con-
structed on the subgrade or subbase for the pur-
pose of serving one or more functions such as
distributing load, providing drainage, minimiz-
ing frost action, etc. 3. The lowest layer in a
pavement construction.

base-court, basse-cour l.A yard or ward
behind the outer bailey of a castle. 2. On a farm,
a service yard often reserved for fowl. 3. A lesser
or service courtyard in any building. 4. (Brit.) A
lower court of law.

base elbow A cast-iron pipe elbow having a
baseplate or flange cast on it, by which it is
supported.

base exchange Same as cation-exchange soft-
ening of water.

base flashing l.The flashing provided by
upturned edges of a watertight membrane on a
roof. 2. Any metal or composition flashing at
the joint between a roofing surface and a vertical
surface, such as a wall or parapet.

base flashing

base line A surveyed line which has been
established with more than usual care, and to
which surveys are referred for coordination and
correlation.

base map In urban planning, a map indicating
the significant existing physical features of an area,
i.e., streets, rivers, parks, railroads, etc., and serv-
ing as a foundation for all subsequent mapping.

basement 1. Usually the lowest story of a
building, either partly or entirely below grade.
Also see cellar, American basement. 2. The
lower part of the wall or walls of any building. 3.
The substructure of a column or arch. Fre-
quently, the applicable building code specifies
that only one floor level shall be classified as a
basement. Also see American basement, English
basement, French basement, raised basement,
walk-out basement.

basement barn A term sometimes used for
bank barn.

basement house A house whose rooms are
mainly located above ground level but whose
entrance, from the exterior, is at ground level or
one floor above.

basilica

basement soil See subgrade, 1.

basement stair A stairway connecting the base-
ment or cellar with the level of the living area.

basement wall A foundation wall which
encloses a usable area under a building.

basement window A window in the base-
ment of a residence.

base metal The metal to be welded or soldered
(as distinguished from filler metal which is
deposited during the joining process).

base molding Molding used to trim the upper
edge of interior baseboard; a base cap.

BASE MOLDING

base molding and base shoe

baseplate 1 . A metal plate used to distribute a
nonuniform load. 2. A metal plate on which a
column rests. 3. A metal plate used as a founda-
tion for heavy machinery; a bed plate.

base ply In roofing: the layer of felt secured to
the deck over which a built-up roof is applied.

base screed A metal screed having expanded
or short perforated flanges; acts as a dividing
strip between plaster and cement; provides a
ground (guide) to indicate proper thickness of
plaster and cement.

base sheet Saturated and/or coated felt sheet-
ing which is laid as the first ply in a built-up
roofing membrane.

base shoe, base shoe molding, floor mold-
ing, shoe molding, carpet strip A mold-
ing used next to the floor on interior baseboard.

base shoe corner A molding piece or block
applied in the corner of a room to eliminate the
need for mitering the base shoe.

base table A base molding, 2.

base tee A pipe tee with a connected baseplate
for supporting it.

base temperature The reference temperature
given in the definition for degree-day.

base tile The lowest course of tiles in a tiled wall.

Basic Building Code A model code that has
been widely used in the US, particularly in the
northeastern and midwestern states.

basic creep In concrete construction, creep
occurring without the migration of moisture to
(or from) the concrete.

basic insulation level (BIL) The insulation
capability of an item of electrical equipment
(e.g., a transformer) to withstand specified volt-
age surges.

basic services The services performed by an
architect during the following five phases of a
project: schematic design; design development;
construction documents; bidding or negotiation;
and contract administration.

basic wind speed The wind speed that is used in
determining wind load on a structure before other
factors (such as height above the ground and the
effects of shielding) are taken into account.

basil Same as bezel.

basilica l.A Roman hall of justice, typically
with a high central space lit by a clerestory and
lower aisles all around it, and with apses or exe-
drae for the seats of the judges. 2. The form of
the early Christian church, a central high nave
with clerestory, lower aisles along the sides only,

basilica: Typical plan. A, D, apse; B, B', secondary apse;

C, high altar; D, bishop's throne; G, transept; H, nave;

J , T , aisles

basin

with a semicircular apse at the end. Often pre-
ceded by a vestibule (narthex) and atrium. In
larger basilicas, there are often transepts, and
sometimes five aisles.

basin 1. A somewhat shallow vessel for holding
water (or the like). 2. A shallow tank or natural
or artificial depression containing water.

basin fittings The trim, 3 on a water basin that
usually includes one or more faucets, a trap, an
overflow pipe, and adapters.

basket See bell, 1.

basket capital A capital having a shape similar
to an inverted bell that is ornamented with sur-
face work similar to basket weave.

basket-handle arch, basket arch A flat-
tened arch whose ellipse-like shape is deter-
mined by three arcs that are interconnected,
each arc being drawn from a different center of
curvature; also called a semielliptical arch or an
elliptical arch.

basket-handle arch

basket newel A newel at one end of a handrail
at the bottom of a flight of stairs; has the overall
shape of a tall cylindrical basket.

basket weave A checkerboard pattern of bricks,
flat or on edge.

basket weave

basket-weave bond A brick bond arrange-
ment having a checkerboard pattern.
bas-relief, basso-relievo, basso-rilievo

A carving, embossing, or casting moderately
protruded from the background plane; low
relief.

basse-cour See base-court.

basso-rilievo, basso-relievo See bas-relief.

basswood, American linden A cream-
colored, fine-textured, moderately low-density
wood of North America; used extensively for ply-
wood, lumber core, and trim.

bas-taille Same as bas-relief.

bastard A nonstandard item; one of irregular or
abnormal size or shape or of inferior quality.

bastard ashlar, bastard masonry 1. Stone, in
thin blocks, used to face a brick or rubble wall;
square-hewn and laid to resemble ashlar. 2. Ashlar
stones which are only roughly dressed at the quarry.

bastard bond Same as header bond.

bastard file One of four principal classifica-
tions of files which are graded according to
coarseness (coarse, bastard, second, smooth).

bastard granite A quarry term for gneissic
granites; not considered a true granite; used in
wall construction.

bastard joint Same as blind joint.

bastard masonry See bastard ashlar.

bastard pointing See bastard tuck pointing.

bastard-sawn See plain-sawn.

bastard spruce Same as Douglas fir.

bastard stucco Plaster applied in three coats: a
scratch, a brown, and a finish coat.

bastard tuck pointing, bastard pointing

An imitation tuck pointing in which the exter-
nal face is parallel to the wall, but projects
slightly and casts a shadow.

bastel house, bastille house, bastle house

A partly fortified house whose lowest story usu-
ally is vaulted.

bastide 1 . A medieval settlement built for defense
purposes and generally laid out with a geometric
plan, esp. in France. 2. A small rural dwelling in
southern France.

bastille, bastile 1 . A fortification or castle, fre-
quently used as a prison. 2. A tower or bulwark
in the fortifications of a town.

bastille house A bastel house.

bastion A defense work, round, rectangular, or
polygonal in plan, projecting from the outer wall
of a fortification, principally to defend the adja-
cent perimeter.

bastle house See bastel house.

baston, baton, batoon l.A torus. 2. See
batten.

batten

"■■■ ,

bastide, 1

bat 1 . A piece of brick with one undamaged end;
also called a "brickbat." 2. A unit of batt insula-
tion. 3. A piece of wood used as a brace. 4. A
batten.

- I

bat, 1

Bataan mahogany Same as tanguile.

bat bolt A bolt barbed or jagged at the butt, or

tang, to give it a firmer hold.
batch 1 . A quantity of concrete or mortar

mixed at one time. 2. A quantity of adhesive

mixed at one time.
batch box A container of known volume used

to measure and mix the constituents of a batch

of concrete, plaster, or mortar, to ensure proper

proportions.
batched water The mixing water added to a

concrete or mortar mixture before or during the

initial stages of mixing.
batcher A device for measuring ingredients for

a batch of concrete.
batching Weighing or measuring the volume of

the ingredients of a batch of concrete or mortar,

and then introducing these ingredients into a

mixer.
batch mixer A machine that mixes grout,

mortar, or concrete in batches in contrast to one

that mixes continuously.

batch plant An operating installation of equip-
ment including batchers and mixers as required
for batching or for batching and mixing concrete
materials; also called a mixing plant when mixing
equipment is included.

batement light A window with its lower edge
cut diagonally rather than horizontally so as to
fit an arch or rake below; esp. used in perpendic-
ular tracery.

bath 1 . An open tub used as a fixture for bathing.

2. The room containing the bathtub. 3. (pi.) The
Roman public bathing establishments, consisting
of hot, warm, and cool plunges, sweat rooms, ath-
letic and other facilities; balnea, thermae.

bathhouse 1 . A building equipped with bathing
facilities. 2. A small structure containing dressing
rooms or lockers for bathers, as at the seaside.

bathroom A room containing a water closet, a
lavatory, and a bathtub and/or shower.

bathroom cabinet Same as medicine cabinet.

bath trap The P-trap in the waste line of a
bathtub.

bathtub A tub for bathing, usually a fixed
plumbing installation designed for one person.

bat insulation Same as batt insulation.

baton A batten.

batons rompus Short, straight pieces of con-
vex molding, as those forming Norman or
Romanesque chevrons and zigzags.

batoon A batten.

batt A unit of batt insulation.

batted work, broad tooled A hand-dressed
stone surface scored from top to bottom in nar-
row parallel strokes, (usually 8 to 10 per inch)
(20 to 25 per centimeter), by use of a batting
tool. The strokes may be vertical or oblique.

batten l.A narrow strip of wood applied to
cover a joint along the edges of two parallel
boards in the same plane. 2. A strip of wood
fastened across two or more parallel boards to
hold them together; also called a cross batten.

3. A flat strip of wood attached to a wall as a
base for lathing, plastering, etc.; also called a
furring strip. 4. In roofing, a wood strip applied
over boards or roof structural members; used as
a base for the attachment of slate, wood, or
clay-tile shingles. 5. See board and batten.
6. A board usually 2 in. (5 cm) to 4 in. (10 cm)

battenboard

thick and usually used as a lathing support or in
flooring. 7. A steel strip used to secure metal
flooring on a fire escape. 8. On a theater stage,
a strip of wood to frame, stiffen, or reinforce
a flat, or to fasten several flats together. 9. On a
theater stage, length of hollow metal of round,
square, or rectangular cross section used in con-
nection with stage rigging to hang scenery or
lighting equipment, such as a pipe batten or
lighting batten.

battenboard See coreboard.

battened column A column consisting of two
longitudinal shafts, rigidly connected to each
other by batten plates.

battened door A wood door without stiles
which is constructed of vertical boards held
together by horizontal battens, 2, on the back
side. Also called a batten door, ledged door, and
unframed door.

batten seam A seam in metal roofing which is
formed around a wood strip.

TIT

i i

battened door

battened shutters Solid, unframed, window

shutters held together by horizontal battens, 2;

similar in construction to small battened

doors.
battened wall, strapped wall A wall to

which battens have been affixed.
battening Narrow battens or wood strips

attached to a wall for the purpose of receiving

lath and plaster.
batten plate, stay plate A steel plate used to

join two parallel components (such as flanges or

angles) of a built-up structural column, girder, or

strut; designed to transmit shear between the

two components.
batten roll, conical roll In metal roofing, a

roll joint formed over a triangular-shaped wood

piece.

batten seam

batter To incline from the vertical. A wall is
said to batter when it recedes as it rises.

batter board l.One of a pair of horizontal
boards which are nailed (at right angles to each
other) to three posts set beyond the corners of a
building excavation; used to indicate a desired
location; strings, fastened to these boards, are
used to indicate the exact corner of a building.
2. One of the boards set across a pipe trench to
carry a cord or wire grade line.

PLUMB DOWN
BUILDING LIKES TO LOCATE
REPRESENTED CORNER OF
BY CORDS FOUNDATION

batter boards

batter brace, batter post A diagonal brace

which reinforces one end of a truss.
battered A term descriptive of a surface that is

inclined or tilted with respect to the vertical; for

example, a battered wall.
battered wall A wall having a batter.

bay

battered wall

batter level A device for measuring the incli-
nation of a slope.

batter pile, brace pile, spur pile A pile dri-
ven at an inclination to the vertical to provide
resistance to horizontal forces.

batter post 1 . See batter brace. 2. A post at one
side of a gateway or at a corner of a building for
protection against vehicles.

batter rule In constructing a battered wall, a
device for regulating the inclination.

batter stick A tapered board which is hung ver-
tically; used to test the batter of a wall surface.

battery 1. A combination of two or more elec-
tric cells capable of storing and supplying direct
current by electrochemical means. 2. Any group
of two or more similar adjacent plumbing fix-
tures which discharge into a common horizontal
waste or soil branch.

batting Same as batted work.

batting tool A mason's chisel usually 3 to 4^2
in. (7.6 to 11.4 cm) wide, used to dress stone to
a striated surface. See batted work.

batt insulation A flexible blanket-type ther-
mal insulation, commonly used as insulation
between studs or joists in frame construction; also

^ *fl£&

used as an acoustical material or a component in
sound-insulating construction. Usually made
from rock, slag, or glass fibers. Sometimes has a
vapor barrier on one side or is entirely enclosed
in paper with a vapor barrier on one side. Nom-
inally 16 (40.6 cm) or 24 in. (61 cm) wide, and
approx. 1 to 6 in. (2.5 to 15 cm) thick.

battlement, embattlement l.A fortified
parapet with alternate solid parts and openings,
termed respectively "merlons" and "embrasures"
or "crenels" (hence crenelation). Generally for
defense, but employed also as a decorative motif.
2. A roof or platform serving as battle post. 3. A
decorative motif having the general shape of a
battlement.

»- —

batt insulation installed on underside of subflo

battlement

Bauhaus A school of design established in
Weimar, Germany, by Walter Gropius in 1919.
The term became virtually synonymous with
modern teaching methods in architecture and
the applied arts, and with a functional aesthetic
for the industrial age; often characterized by
emphasis on functional design, the use of a repet-
itive interval between members of the framework
of a building, and the maintenance of purely geo-
metric forms. Often, major building components
such as bays, doors, and windows are placed to
coincide with this repetitive interval, although
the building itself may be asymmetrical.

baulk Same as balk.

baulk-tie See balk-tie.

bawn l.A fortified enclosure, often of mud or
stone, surrounding a farmyard or castle; esp. in Ire-
land. 2. A fortified house (especially during the
17th century) with massive walls, designed to
serve as a haven of refuge in the event of an
enemy attack; also see garrison house.

bay 1. Within a structure, a regularly repeated
spatial element defined by beams or ribs and
their supports. 2. A protruded structure with a

bayle

ztekr

apes

bay of an arcade

bay window. 3. The free or light space between
sash bars. 4. In landscape architecture, a recess
or alcove formed by plants in a design. 5. In plas-
tering, the distance between screeds employed
for working the floating of plaster.

bayle The open space contained between the first
and second walls of a fortified castle; a bailey, 1.

bay leaf A stylized laurel leaf used in the form
of a garland to decorate torus moldings.

bayonet holder, bayonet socket A type of
lamp holder which provides mechanical support
and electric connections for an electric light
bulb; esp. used in Great Britain.

bayonet saw Same as saber saw.

bay stall (Brit.) A built-in window seat.

bayt l.A Muslim dwelling, generally for one
family, e.g., a tent or house. 2. In the early Mus-
lim palace complex, a separate dwelling unit.

bay window A window that protrudes from a
wall, usually bowed, canted, polygonal, segmen-
tal, semicircular, or square-sided in plan; typi-
cally one story in height, although sometimes
higher; occasionally corbeled out from the face

bay window

of the wall, as an oriel; also see angled bay win-
dow, bow window, cant window.

bazaar A marketplace where goods are exposed
for sale; esp. in the East, consisting either of
small shops or stalls in a narrow street or series of
streets, or of a certain section of town under one
roof and divided into narrow passageways.
b/b Symbol for course-aggregate factor.
bbl Abbr. for "barrel."
BC Abbr. for "building code."
BCM Abbr. for "broken cubic meter."
BCY Abbr. for "broken cubic yard."
bd. In the lumber industry, abbr. for "board."
bd. ft. In the lumber industry, abbr. for "board

foot."
bdl In the lumber industry, abbr. for "bundle."
beacon house Same as lighthouse.
bead 1. A bead molding. 2. A narrow wood strip,
molded on one edge, against which a door or win-
dow sash closes; a stop bead. 3. A strip of metal or
wood used around the periphery of a pane of glass
to secure it in a frame, ventilator, or sash; a stop.
4. A pearl-shaped carved decoration on moldings
or other ornaments, usually in series, or in con-
junction with other shapes; a beading. Also see
bead and reel molding. 5. A molding decorated
with beading; an astragal, 1 or chaplet. 6. Used in
combination with other terms to describe the

beaking joint

function or position of a beaded molding, such as
quirk bead, angle bead, corner bead, etc. 7. The
act of carving or running a bead; beading. 8. In
metal roofing or flashing, the shape formed by
folding a narrow strip of the edge flat or rolling it
into a tube in order to stiffen or fasten the metal.

9. A factory-formed light-gauge metal strip hav-
ing one or two expanded or short perforated
flanges and variously shaped noses; used at the
perimeter of plastered surface as a casing bead or
plaster stop, and at corners to reinforce the edge.

10. A hardened drop of excess paint or varnish.

1 1 . A narrow, convex strip of sealant, such as
caulking or glazing compound. 12. A weld bead.

bead, butt and square Similar to bead and butt
but having the panels flush on the beaded face
only, and showing square reveals on the other.

bead and butt, bead butt, bead butt work
Framed work in which the panel is flush
with the framing and has a bead run on two
edges in the direction of the grain; the ends are
left plain.

bead and butt

bead and flush panel See beadflush panel.

bead and quirk See quirk bead.

bead and reel, reel and bead A semiround
convex molding decorated with a pattern of
disks alternating with round or elongated beads.

bead butt, bead butt work See bead and butt,
beaded clapboard See clapboard,
beadflush panel, bead-and-flush panel A

panel which is flush with the surrounding fram-
ing and finished with a flush bead on all edges of
the panel.

bead house A dwelling for poor religious peo-
ple, located near the church in which the
founder was interred, and for whose soul the
beadsmen or beadswomen were required to pray.

beading Collectively the bead moldings used in
ornamenting a given surface; also see bead.

beading plane, bead plane A plane having
a curved cutting edge for shaping beads in wood.

bead-jointed Said of a carpentry joint having a
bead along the edge of one piece to make the
joint less conspicuous.

bead molding l.A small, convex molding of
semicircular or greater profile; also called a half
round; a roundel; a baguette. 2. Same as pater-
noster.

bead molding

bead plane See beading plane.

bead weld Same as surfacing weld.

beadwork Same as beading.

beakhead An ornament; any of several fantastic,

animal-like heads with tapered, down-pointed

beaks; frequently used in richly decorated Norman

doorways. Also see catshead.
beakhead molding, bird's-beak molding

Same as beak molding, 2.
beaking joint A joint formed by several

heading joints occurring in one continuous

line; esp. used in connection with the laying of

floor planks.

beak molding

beak molding 1 . A pendant fillet with a chan-
nel behind it on the edge of a corona, larmier, or
stringcourse, etc., so called because in profile it
resembles a bird's beak. 2. A molding enriched
with carved birds' heads or beaks.

beak molding

beam 1 . A structural member whose prime func-
tion is to carry transverse loads, as a joist, girder,
rafter, or purlin. The term beam may be modified
by an adjective indicating its location; as, for
example, an end beam or side beam. See anchor
beam, binding beam, breastsummer beam, cam-
ber beam, ceiling beam, collar beam, cross beam,
dragon beam, floor beam, ground beam, hammer
beam, I-beam, laced beam, perimeter beam,
summerbeam, tie beam, top beam, wind beam.
2. A group of nearly parallel rays of light.

beam anchor, joist anchor, wall anchor
A metal tie used to anchor a beam or joist to a
wall, or to tie a floor securely to a wall.

beam-and-column construction Same as
post-and-lintel construction.

beam-and-girder construction A system of
floor construction in which the load is distrib-
uted by slabs to spaced beams and girders.

beam-and-slab floor A floor system in which
a concrete floor slab is supported by reinforced
concrete beams.

beam bearing plate A foundation plate (usu-
ally of metal) placed beneath the end of a beam,
at its point of support, to distribute the end load
at the point.

beam blocking l.Boxing-in or covering a
joist, beam, or girder to give the appearance of
a larger beam. 2. Strips of wood used to create a
false beam.

beam bolster A rod which provides support for
steel reinforcement in formwork for a reinforced
concrete beam.

beam bottom The soffit of a beam.

beam box Same as wall box.

beam brick A face brick which is used to bond
to a poured-in-place concrete lintel.

beam casing The enclosure of a steel beam
in concrete or in an exfoliated vermiculite
plaster; used to increase the fire resistance of
the beam.

beam ceiling l.A ceiling, usually of wood,
made in imitation of exposed floor beams with
the flooring showing between. 2. The underside
of a floor, showing the actual beams, and fin-
ished to form a ceiling.

beam»column A beam which transmits an
axial load as well as a transverse load.

beam compass An instrument used to draw
large circles or arcs of circles for full-sized work-
ing drawings; has a long horizontal bar on which
two movable heads slide to and fro, one of which
carries a pencil, and the other a sharp-pointed
pin or tracer, the distance between them deter-
mining the radius of the circle.

beam compass

beam cutoff angle The angle, measured from
the principal axis of the intensity of a light
source, at which the light source cannot be seen.

beam divergence (Brit.) Same as beam
spread.

beam encasement Same as beam casing.

beam fill, beam filling Masonry, brickwork,
or cement fill, usually between joists or horizon-
tal beams at their supports; provides increased
fire resistance.

beam form A form which gives the necessary
shape, support, and finish to a concrete beam.

bearing wall

beam hanger 1. A strap, wire, or other hard-
ware device which supports framework from
structural members. 2. A stirrup, 4.

beam infilling See infilling.

beam iron Same as beam anchor.

beam link The segment of a concrete beam
between a brace and a column or between braces.

beam pocket 1 . In a vertical structural mem-
ber, an opening to receive a beam. 2. An open-
ing in the form for a column or girder where the
form for an intersecting beam is framed.

beam saddle Same as beam hanger.

beam side In a concrete form for a beam, the
side panels of the form.

beam spread The angle between two direc-
tions (on opposite sides of the axis of a light
beam, and in the same plane as the beam axis) in
which the light intensity equals a stated percent
of a maximum reference intensity.

beam-spread angle The width of a light
beam, measured in degrees, at the meeting point
between two imaginary lines at which the light
intensity drops to half its maximum value.

beam test A test of the flexural strength (mod-
ulus of rupture) of concrete from measurements
on a standard unreinforced concrete beam.

bearer l.Any horizontal beam, joist, or mem-
ber which supports a load. 2. A support for a
landing or winder in a stair. 3. The ribbon board
in balloon framing, which supports second-floor
joists. 4. A horizontal member of a scaffold upon
which the platform rests and which may be sup-
ported by ledgers.

bearer bracket Same as roofing bracket.

bearing 1. A bearer. 2. That portion of a beam,
truss, or other structural member which rests on
the supports. 3. The support for a shaft, axle, or

POINT

bearing, 4

trunnion. 4. In surveying, the horizontal angle
between a line and a reference meridian adjacent
to the quadrant in which the line lies.

bearing bar l.A wrought-iron bar placed on
masonry to provide a level support for floor
joists. 2. A load-carrying bar which supports a
grating and which extends in the direction of
the grating span.

bearing bar centers The distance between
centers of bearing bars in a metal grating.

bearing block A block which distributes a
load on the surface beneath the block.

bearing capacity l.The load per unit area
that can be supported safely by the ground. 2.
See pile bearing capacity. 3. The pressure that
can be exerted on soil or soil rock without exces-
sive yield. 4. Of a pile, the load required to pro-
duce a condition of failure.

bearing distance, span The length of a beam
between its bearing supports.

bearing length The length of a structural
beam between its supports.

bearing partition See load-bearing partition.

bearing pile A pile which carries a vertical load.

bearing plate A steel slab which is placed under
a beam, column, girder, or truss to distribute the
end reaction from the beam to its support.

bearing pressure The pressure on a bearing, 2 ;
the load on a bearing surface divided by its area.

bearing stone A masonry unit in a wall that
can support a load other than the units of which
the wall is composed.

bearing stratum The rock or soil stratum (a)
which carries the load transferred to it by a cais-
son, pile, or the like or (b) on which a concrete
footing or mat bears.

bearing strength 1 . The maximum load that a
column, footing, joint, or wall can sustain at fail-
ure, divided by the effective bearing area. 2. The
non-destructive limit of a pipe load; used to
determine its supporting strength in the field.

bearing stress See bearing pressure.

bearing test A field or laboratory test to deter-
mine the bearing capacity of a soil sample, indi-
vidual pile, pile foundation, or the like.

bearing wall A wall capable of supporting an
imposed load. Also called a structural wall or
loadbearing wall.

beaumontage

beaumontage A resin, beeswax, and shellac
mixture used for filling small holes or cracks in
wood or metal.

Beaux-Arts style A grandiose architectural
style as taught at the Ecole des Beaux Arts in
Paris primarily in the 19th century, widely
applied until 1930 to large public buildings such
as courthouses, libraries, museums, railroads,
and to some pretentious residences. Character-
istics often include formalism in design, sym-
metrical plans, heavily rusticated arched
masonry, ashlar stone bases with rusticated
stonework, especially on the ground floor and
raised basement levels; sculptured figures; a
massive and symmetric facade, often with a pro-
jecting central pavilion; a monumental attic
story; commonly decorated with dentils;
enriched entablatures; monumental flights of
stairs; classical columns often set in close pairs;
banded columns, engaged columns, coupled
pilasters; highly decorated pilastered parapets;
balconies; sculptured spandrels; decorative
brackets; sculptured figures; ornamental details
such as cartouches, floral patterns, Greek key
designs, ornamental keystones, medallions;
elaborately decorated panels, and the like; the
roof, commonly a flat or low-pitched, hipped, or
a mansard roof; often, domes and rotundas; rec-
tangular windows symmetrically placed, with
lintels overhead; arched dormers, balustraded
windows, pedimented windows, or windows
with balconets; doors, commonly paneled with
a glass-paneled canopy over the primary entry-
way, flanked by columns or pilasters; a wrought-
iron grille on the exterior side of the entry door.
Also called Beaux- Arts Classicism.

beaver board Same as composition board.

bed 1. In masonry and bricklaying, the side of a
masonry unit on which it lies in the course of
the wall — the underside when placed horizon-
tally. 2. The layer of mortar on which a masonry
unit is set. 3. The lower surface or side of a slate.
4. To set a glass pane in place with putty. 5. In
layered stone used for building, a surface parallel
to the stratification. 6. A layer (stratum) of rock
between two bedding planes.

bed chamber An apartment or chamber intended
for a bed, or for sleeping and resting.

bedding 1 . Mortar, putty, or other substance used
to secure a firm and even bearing, as putty laid in

the rabbet of a window frame, or mortar used to
lay bricks. 2. A base which is prepared in soil or
concrete for laying masonry or concrete.

bedding coat The plaster coat which receives
aggregate or other decorative material, impinged
or embedded in its surface before it sets.

bedding course l.The first layer of mortar
at the bottom of masonry. 2. A cushion
course.

bedding dot A small spot of plaster built out to
the face of a finished wall or ceiling; serves as a
screed for leveling and plumbing in the applica-
tion of plaster.

bedding plane The surface at which two beds,
layers, or strata join in stratified rocks.

bedding plants Annual and subtropical plants
used for seasonal effects in landscaping.

bedding putty A putty, 1 that is placed in the
rabbet of a window-opening in which the glass is
bedded.

bedding stone A flat marble slab used by
masons to check the flatness of rubbed bricks.

bed glazing See back putty.

bed joint l.A horizontal layer of mortar on
which masonry units are laid. 2. One of the
radial joints in an arch. 3. A horizontal crack in
a massive rock.

bed joint, 1

bed molding 1 . A molding of the cornice of an
entablature situated beneath the corona and
immediately above the frieze. 2. The lowest mem-
ber of a band of moldings. 3. Any molding under
a projection, as between eaves and sidewalls.

bed place An alcove into which a bed is
located; found, for example, in many houses in
Europe and their derivatives.

bedplate A plate, frame, or platform which sup-
ports a heavy object such as a machine or fur-
nace; a baseplate.

100

Belfast truss

BED MOLDING

FRIEZE

bed molding, 3

used for the removal or reduction of suspended
solid contaminants.

beech, beechwood A moderately high-
density, fine-grained, durable, strong hardwood
of North America and Europe. Whitish to light
red-brown in color; used for small wood-turned
parts and flooring.

beehive house Same as trullo.

beehive oven Same as bake oven.

beehive tomb, tholos tomb A monumental
underground tomb in the form of a beehive, used
in the Mycenaean period.

bed places

bed putty Same as back putty.

bedrock The hard, solid rock at the earth's sur-
face or underlying surface soil; can be utilized as
a firm foundation for a building.

bedroom A room suitably furnished for sleeping.

bedroom community See satellite commu-
nity; also called a dormitory suburb.

bed sill A horizontal timber at the base of a
building of timber-framed construction; the tim-
ber rests on, or is set into, the ground; same as
groundsill, 2.

bedstone A large flat stone that supports a
structural member.

bed surface Of a brick, the in situ non-vertical
surface intended to be joined by mortar.

bed-type filter In a water supply line, a filter
containing a porous medium through which the
water is forced as a result of the water pressure;

beehive tomb, section

beetle A heavy mallet or rammer; used for dri-
ving stones into pavement, for driving wedges,
etc.; a maul.

beggin, begging l.A dwelling of larger size
than a cottage. 2. In the north of England and in
Scotland, a house. 3. A term especially applied
to a hut covered with mud or turf.

beit hilani 1 . In northern Syria, a type of palace
in the first millenium B.C. having a forward sec-
tion with two large transverse rooms, a portico
with one to three columns, and a throne room.
2. In ancient Assyrian architecture, the pillared
portico of a beit hilani, 1 .

bel A unit of sound level which denotes the ratio
between two quantities proportional to power;
the number of bels equals the logarithm of this
ratio, to the base 10; 1 bel = 10 decibels.

belection See bolection molding.

Belfast roof A bowstring roof.

Belfast sink A plumbing fixture consisting of a
deep-sided basin, often made of stoneware, with
a water supply and drain.

Belfast truss A bowstring truss, for large spans,
which is constructed entirely of timber compo-
nents; the upper member is bent, and the lower
member is horizontal.

101

belfry

belfry l.A bell tower, either attached to a
church or standing alone. 2. A timber frame-
work in a steeple that supports a bell.

Belgian block A type of paving stone gener-
ally cut in a truncated, pyramidal shape; laid
with the base of the pyramid down.

Belgian truss See Fink truss.

belite A constituent of portland cement clinker;
when pure, known as dicalcium silicate.

bell l.The body of a Corinthian capital or a
Composite capital, with the foliage removed; also
called a vase or basket. 2. The portion of a pipe
which is enlarged to receive the end of another
pipe of the same diameter for the purpose of mak-
ing a joint; also called a hub.

bell, 1

kfc

bell, 1

bell-and-spigot joint, bell-and-socket joint,
spigot-and-socket joint A connection be-
tween two sections of pipe, the straight spigot
end of one section is inserted in the flared-out
end of the adjoining section; the joint is sealed
by a caulking compound or with a compressible
ring.

bell arch A round arch supported on large cor-
bels, giving rise to a bell-shaped appearance.

belli

bell cage The timber framework which sup-
ports the bells in a belfry or steeple.

bell-and-spigot joint

bell cage

bell canopy A gable roof to shelter a bell.

bell capital 1 . A bell-shaped capital. 2 . The bell-
shaped core of a Corinthian capital to which the
leaves and volutes appear to be attached.

102

bell pull

bellcast eaves Same as flared eaves.
bellcast roof Same as a bell roof.

bell cote A small belfry astride the ridge
of a church roof, often crowned with a small spire.

bell cote

bell deck The belfry floor above the lower
rooms in a tower.

belled caisson A caisson having an enlarged
base.

belled excavation A part of a shaft or footing
excavation, usually near the bottom and bell-
shaped.

belled pier A pier having an enlarged end at
the bottom of its shaft, often in the shape of a
bell-like truncated cone.

bellexion molding See bolection molding.

bellflower A bell-shaped floral ornament; com-
monly, one of a string of such decorative elements.

bell gable A wall gable having one or more
openings for bells.

bell house A tower-like building for housing
bells, esp. in Ireland.

bellied Having a convex or bulging form.

S» ( «-

bell gable

belling In pier, caisson, or pile construction
enlarging the base of a foundation element
to increase its bearing area at the bearing
stratum.

bell joint See bell-and-spigot joint.

bellows expansion joint In a run of piping,
a joint formed with flexible metal bellows
which compress or stretch to compensate for
linear expansion or contraction of the run of
piping.

bell pull A device once used to summon ser-
vants in an elegant home; in each room, the
bell pull consisted of a small handle connected
to a wire that was mechanically connected to a
bell in the servants' quarters. Thus, a pull on
the handle rang a bell in the servants' quar-
ters; each bell pull produced a sound of differ-
ent pitch, identifying the room calling for
service.

103

bell roof

bell roof A roof having a cross section similar
to that of a bell, flaring out at its lower edge.

bell roof

bell tower A tall structure supporting one or
more bells; may be part of a building or an inde-
pendent structure; also see belfry.

bell transformer A small transformer which
supplies power, at low voltage, for operating a
doorbell or the like.

bell trap A type of bell-shaped trap used in floor
drains; its use is prohibited by the National
Plumbing Code.

bell turret A small tower, usually topped with
a spire or pinnacle, and containing one or more
bells.

bell 'wire Small-diameter wire of low current-
carrying capacity; covered with insulating mate-
rial rated at 30 volts or less.

below grade Recessed below ground level.

belowstairs In the basement.

belt conveyor A power-driven endless belt
that runs on idler wheels; used to carry building
materials, etc.

belt course l.A horizontal band of masonry
extending horizontally across the facade of a
building and occasionally encircling the entire
perimeter; usually projects beyond the face of
the building and may be molded or richly
carved. Also called a stringcourse or band
course; called a sill course if set at windowsill
level. 2. A horizontal board across front face or
around a building, often having a molding.

■>-T

bell turret

belt i

belt-driven machine Any machine powered
by an external source connected to the machine
by one or more belts.

belt loader A machine used in excavation; a
layer of earth is removed with a cutting edge or
rotating auger; then the excavated material is
elevated by means of a conveyor belt so that it
can be loaded into a hauling unit; a separate
prime mover usually is required to move the
machine forward.

belt sander A portable tool having a power-
driven abrasive -coated continuous belt; used to
smooth surfaces.

beltstone One of the stones in a belt course.
beluardetto In military architecture, a small
bastion on a continuous parapet of a medieval

104

bending beam

fort; usually located in a large ditch in front of
the main rampart.
belvedere 1 . A rooftop pavilion from which a
vista can be enjoyed. 2. A gazebo. 3. A mirador.

belvedere, 1 of the Vatican

bema l.A transverse space in a church a few
steps above the floor of the nave and aisles, and
separating them from the apse. 2. In a syna-
gogue, a raised pulpit from which the Torah
(Holy Bible) is read.

bematis Same as diaconicon, 1.

bench l.A long seat, usually of wood, with or
without a back, usually for several persons. 2. A
berm, 6. 3. Same as pretensioning bed.

bench brake A bench-mounted machine used
for bending sheet metal.

benched foundation Same as stepped foun-
dation.

bench end A terminal wood facing on a
church pew, often decorative.

bench hook, side hook Any device used on
a carpenter's bench to keep work from moving
toward the rear of the bench.

BENCH HOOK

bench hook

benching 1. Concrete laid on the side slopes of
drainage channels where the slopes are inter-
rupted by manholes, etc. 2. Concrete laid on
sloping sites as a safeguard against sliding. 3.

Concrete laid along the sides of a pipeline to
provide additional support.

bench mark In surveying, a marked reference
point on a permanent, fixed object, such as a
metal disk set in concrete, whose elevation (above
or below an adopted datum) is known and from
which the elevation of other points or objects
may be determined.

bench plane A plane, 1 used primarily in
benchwork on flat surfaces, as a block plane or
jack plane.

bench sander A stationary power tool (usu-
ally mounted on a table or stand) which is
equipped with a rotating abrasive disk or belt;
used to smooth surfaces of material held
against it.

bench stake Same as stake, 1.

bench stop A bench hook which is used to
fasten work in place, often by means of a
screw.

bench table A projecting course of masonry at
the foot of an interior wall, or around a column;
generally wide enough to form a seat.

bench terrace A level step cut into a hill-
side grade.

bench trimmer, trimming machine, guil-
lotine A machine for cutting the ends of two
pieces of wood to any desired angle.

bench vise An ordinary vise, 1 fixed to a
bench, which is used to hold a material or com-
ponent while it is being worked on.

benchwork Any work performed at a bench
rather than on machines or in the field.

bend See pipe bend.

bender For pipes, see hickey, 2.

bending beam See tie beam.

105

bending iron

bending iron A tool used to straighten or to
expand flexible pipe, esp. lead pipe.

bending moment The moment which pro-
duces bending at a section of a beam or other
structural member; equal to the sum of
moments taken about the center of gravity of
that section.

bending pin One of a number of pins in a
curved line which are used in bending lead
pipe.

bending schedule A chart showing the
shapes and dimensions of every reinforcing bar
and the number of bars required on a particular
job; prepared by the designer or detailer of the
reinforced concrete structure.

bending strength The ability of a structural
member to resist breakage when subject to
one or more external forces that cause it to
bend.

bending stress The tensile or compressive
stress resulting from the application of a non-
axial force on a structural member.

bending tool Same as hickey.

bend radius The smallest radius of curvature
into which a material can be bent without
damage.

beneficial occupancy The use of a project or
portion thereof for the purpose intended.

beneficiation The improvement in the physi-
cal or chemical properties of a material by the
removal or modification of undesirable compo-
nents or impurities which it contains.

benefits (mandatory and customary)
The personnel benefits required by law (such
as social security, workmen's compensation, and
disability insurance), and by custom (such as
sick leave, holidays, and vacation), and those
which are optional with the individual firm
(such as life insurance, hospitalization programs,
pension plans, and similar benefits).

benitier A basin for holy water, usually set at
the entrance to a church.

bent l.Same as bent frame. 2. A rhizomatous
grass, used where a resilient velvety texture is
required.

bent approach An arrangement of two gate-
ways not in line, so that it is necessary to make a
sharp turn to pass through the second; for privacy
in houses or temples, for security in fortifications.

benitier

nr^

HeconquLcK Sloping legs

Goeie ditu
tie

Arched wiiti
lie

mn n

Continuous Mill building

bents, 1

bent bar A longitudinal reinforcing bar which
is bent to pass from one face of a structural mem-
ber to the other face.

bent chisel Same as corner chisel.

bent ferrule A ferrule having a 90° bend.

bent frame One of a number of sections in a
timber framework that is transverse to the
length of a large barn or house of timber-frame

106

beveled edge

bent frame being tilted in place during a barn raising

construction; each section, usually designed to
carry both lateral and vertical loads, was com-
monly constructed on the ground and then
raised to its upright position with the assis-
tance of neighbors, as described under barn
raising.
bent glass Flat glass that has been reshaped
while very hot to form a curved surface.

bent grass See bent, 2.

bentonite A clay, formed from decomposed
volcanic ash, with a high content of the mineral
montmorillonite; has the capability of absorb-
ing a considerable amount of water, and swells
accordingly.

bent shoe A base shoe molding which is bent
on a radius.

bentwood Wood formed to shape by bending,
rather than by carving or machining.

Berlin blue See Prussian blue, 2.

berliner, palladiana A type of terrazzo top-
ping using small and large pieces of marble
paving, usually with a standard terrazzo matrix
between pieces.

berm 1 . A continuous bank of earth alongside a
road; a shoulder. 2. A continuous bank of earth
piled against a masonry wall. 3. A strip of
ground, formed into a ledge to support beams or
pipes. 4. The horizontal surface between a moat
and the exterior slope of a fortified rampart. 5.
In earth excavation work, that portion of the
excavation, usually sloped, left at the perimeter
and removed as the sheeting and bracing are
installed. 6. A narrow terrace or shelf built into
an embankment, or the like, which breaks the
continuity of an otherwise long slope.

Bermuda stone A soft limestone formed pri-
marily of broken shells and coral; usually cut
into rectangular blocks and used in building
construction.

besant See bezant.

bestiary In a medieval church, a group of
carved or painted creatures, often highly imagi-
native and symbolic.

BET. On drawings, abbr. for "between."

bethel A place of worship.

Bethell process A process for preserving wood
by impregnating the cells with creosote under
pressure.

beton A kind of concrete; a mixture of lime,
sand, and gravel.

beton arme Same as reinforced concrete.

beton brut Concrete as it appears when the
framework is removed, so that the concrete sur-
face reflects the framework joints, wood grain,
and fasteners around which it was poured; often
deliberately retained for architectural effect. See
Brutalism.

bettering house An archaic term for poor-
house.

bev In the lumber industry, abbr. for "beveled."

bevel 1 . The angle which one surface of a body
makes with another surface when they are not at
right angles. 2. See door bevel. 3. See lock bevel.
4. A bevel square.

bevel angle In welding, the angle which is
formed between the prepared edge of a member
and a plane perpendicular to the surface of the
member.

bevel board A board cut to any required bevel;
used in framing a roof, stairway, or other angular
wood construction.

bevel chisel A chisel for cutting wood, having
its cutting edge at an angle to the sides.

bevel collar Same as angle collar.

bevel cut Any cut not at right angles.

beveled See bevel.

beveled closer See king closer.

beveled edge Of a door; a vertical door edge
which has a slope of V& in. (0.3 cm) in 2 in.
(5 cm) from a plane perpendicular to the door
face. (See illustration p. 108.)

107

beveled halving

BEVELED EDGE

DOUBLE BEVELED EDGE
beveled edge of a door

beveled halving, bevel halving A half-lap
joint in which the abutting surfaces are cut at an
angle to the plane of the timbers.

beveled joist A floor joist having its upper
edges beveled.

beveled pipe A pipe which has one end angled
so that it mates with a complementary pipe end.

beveled-rabbeted window stool A window
stool which is rabbeted with a beveled profile to
match the slope of the sill of the window frame.

beveled siding See clapboard.

beveled washer A metal washer having a bevel
on one side, permitting a bolt or rod to pass
through it but providing full bearing against a nut.

bevel jack A device for holding wood mold-
ings in cutting a miter.

bevel joint In carpentry, a joint in which two
pieces meet at other than a right angle.

bevel protractor A graduated semicircular
protractor having a pivoted arm; used for mea-
suring or marking off angles.

bevel protractor

bevel siding See clapboard.

bevel square A carpenter's tool, similar to a
square but having a blade that can be adjusted to
any angle.

bezant, besant, byzant An ornament shaped
like a coin or disk; sometimes used in a series in
decorative molding designs.

bezant

bezel, basil The bevel or sloping edge of a cut-
ting tool, as an ax or chisel.

BFP Abbr. for backflow preventer.

Bh Abbr. for Brinell hardness.

Bhn Abbr. for Brinell hardness number.

bhp Abbr. for brake horse power.

BIA Abbr. for the Brick Industry Association,
Reston, VA 201191-1525; formerly the Brick
Institute of America.

biaxial bending The bending of a member
about two perpendicular axes simultaneously.

bib, bibb See bibcock.

bibcock, bib, bibb, bib tap A faucet or stop-
cock which has its nozzle bent downward.

bibc

setting a bevel square

bibliotheca A library; a place to keep books.

bib nozzle Same as bibcock.

bib tap Same as bibcock.

bib valve An ordinary bibcock which is closed
by screwing down a handle, thereby closing a
washer disk onto a seating in the valve.

bicoca A turret or watchtower.

108

billet

bicycle-wheel roof A roof structural system
whose main structural members radiate from the
center to the perimeter of the building, resem-
bling a bicycle wheel.

bid 1 . An offer to perform the work described in
a contract at a specified cost. 2. A complete and
properly signed proposal to do the work, 1 or
designated portion thereof for the sums stipu-
lated therein, supported by data called for by the
bidding requirements.

bid bond A form of bid security executed by the
bidder as principal and by a surety. Also see bid
security and surety.

bid date The date established by the owner or
the architect for the receipt of bids. Also see
bid time.

bidder One who submits a bid for a prime con-
tract with the owner, as distinct from a subbidder
who submits a bid to a prime bidder. A bidder is
not a contractor on a specific project until a con-
tract exists between him and the owner.

bidding documents The advertisement or
invitation to bid, instructions to bidders, the
bid form, and the proposed contract documents
including any addenda issued prior to receipt
of bids.

bidding or negotiation phase The fourth
phase of the architect's basic services, during
which competitive bids or negotiated proposals
are sought as the basis for awarding a contract.

bidding period The calendar period beginning
at the time of issuance of bidding requirements
and contract documents and ending at the pre-
scribed bid time. Also see bid time.

bidding requirements Those documents pro-
viding information and establishing procedures
and conditions for the submission of bids. They
consist of the notice to bidders or advertisement
for bids, instructions to bidders, invitation to bid,
and sample forms. Also see bidding documents.

bidet A low, basin-like plumbing fixture on
which the user sits; used to wash the posterior
parts of the body.

bid form A form furnished to a bidder to be
filled out, signed, and submitted as his bid.

bid guarantee Same as bid security.

bid letting See bid opening.

bid opening The opening and tabulation of
bids submitted by the prescribed bid time and in

conformity with the prescribed procedures. Also
see bid time.

bid price The sum stated in the bid for which
the bidder offers to perform the work, 1.

bid security The deposit of cash, certified
check, cashier's check, bank draft, money order,
or bid bond submitted with a bid and serving to
guarantee to the owner that the bidder, if
awarded the contract, will execute such contract
in accordance with the bidding requirements
and the contract documents.

bid time The date and hour established by the
owner or the architect for the receipt of bids.
Also see bid date.

biennial plant A plant whose life cycle is com-
pleted in two growing seasons.

bifolding door A door having two pairs of
leaves, each pair consisting of an outer and an
inner leaf which are hinged together; each inner
leaf (the one nearest the center line) is hung
from an overhead track; each outer leaf is piv-
oted at the jamb.

bifora Divided by a colonnete into two arches.

bif orate Having two doors or windows.

bifrons Having two fronts or faces looking in
opposite directions, as a double herm.

bifrons

bifronted Same as bifrons.

biga A chariot similar to a quadriga but drawn

by two horses.
BIL See basic insulation level.
bilection molding See bolection molding,
billet 1 . A common Norman or Romanesque

molding formed by a series of circular (but

109

bill of materials

— = .,,

billet, 1

occasionally square) cylinders, disposed alter-
nately with the notches in single or multiple
rows. 2. A steel slab which is placed under a col-
umn to distribute the load, as from the column
to the supporting masonry. 3. A timber which is
sawn on three sides and left rounded on the
fourth. 4. A wood block from which smaller
pieces of structural lumber can be cut.

bill of materials Same as quantity survey.

bill of quantities Same as quantity survey.

bimah A bema, 2.

bimetallic corrosion A type of corrosion
which takes place between two dissimilar met-
als that make prolonged contact with each
other.

bimetallic element A device formed of two
metals which are bonded together, each having a
different coefficient of thermal expansion; used
in temperature-indicating and temperature-
controlling devices.

LEAD_
WIRE -

STATIONARY CONTACTS
/ \
OPEN CLOSED

bimetallic element

i a thermostat

bin A container for storing loose materials, such
as sand or crushed rock.

binder 1. A cementing material, either hydrated
cement or a product of cement or lime and reac-
tive siliceous material, for holding loose material
together. 2. A component of an adhesive com-
position that is primarily responsible for the
adhesive forces which hold two bodies together.
3. A binding agent. 4. A soil binder. 5. A bind-
ing joist. 6. A binding stone. 7. Any member
which binds together components of a framing
structure.

binder course, binding course 1 . In asphaltic
concrete paving, an intermediate course
between the course base and the surfacing mate-
rial; consists of intermediate-size aggregate
bound by bituminous material. 2. A row of
masonry units laid between, and used to bind, an
inner and an outer wall.

binder lead The lead strips used to form the
perimeter around a small pane of glass.

binder soil Material consisting primarily of fine
soil particles (fine sand, silt, clay, and colloids); has
good binding properties. Also called clay binder.

binding agent That liquid portion of a paint
which solidifies and binds together the pigment
particles and develops adhesion to the painted
surface.

binding beam Any timber which serves to tie
together various parts of a frame. For example,
see summerbeam.

binding course See binder course.

binding joist, binder A beam which supports
the common joists of a wood floor above and the
ceiling joists below; commonly, joins two verti-
cal posts.

binding piece A piece of lumber which is
nailed between two opposite beams or joists to
prevent lateral deflection; a straining beam.

binding post A post attached to an electric
cable, wire, or apparatus, for making a connec-
tion to it conveniently.

binding post

binding rafter A longitudinal timber which

supports the roof rafters between the ridge and

the eaves, as a purlin.
binding screw A type of setscrew.
binding stone A stone which bonds masonry

together, as a perpend; a binder, 6.
binding wire Same as tie wire.
binnacle An obsolete term for a dwelling place.
biparting door A double door having two

leaves (one on each side of the center line of the

bit gauge

door) which slide in the same plane and meet at
the center line.

birch A moderately strong, high-density wood
of North America and northern Europe, yellow-
ish white to brown in color; its uniform texture
and figure are well suited for veneer, flooring,
and turned wood products.

birdbath A small puddle of water occurring at a
low spot in paving.

birdcage scaffold A temporary platform,
which supports workers and materials, and has
more than two rows of upright posts and cross-
pieces.

bird peck A small spot or hole in wood usually
caused by a woodpecker. Subsequent tree
growth develops distorted grain around the
injury.

bird's-beak molding See beak molding, 2.

bird screen A frame fitted with a wire mesh; used
to prevent birds from entering an opening, such as
at a chimney hood or a ventilation opening.

bird i

bird's eye An eye-shaped figure in wood
formed by small sharp depressions in the growth
rings. Found particularly in sugar maple but also
in other wood species.

bird's-eye lamp See incandescent direct-light
lamp.

bird's-eye maple Wood of the sugar maple
tree, cut so as to produce a wavy grain with
numerous small, decorative, circular markings.

bird's-mouth l.A notch cut across the grain
at one end of a timber for its reception on the
edge of another piece, such as a wall plate. 2.
The angle between two components, usually
between 90 and 180 degrees.

bird's-mouth joint A wood joint formed by a
cut into the end of a timber to fit over a cross
timber; for example, cut into a rafter.

bird's-mouth, 1

bisellium In ancient Rome, a seat of honor,
or a state chair, reserved for persons of note or per-
sons who had done special service for the state.

bisomus A sarcophagus with two compartments.

bisque A tile that has been fired once but not
glazed.

bit 1 . A small tool which fits in the chuck of a
brace or drill, and by which it is rotated —
thereby cutting or boring a hole. 2. The project-
ing blade of a key which is cut in a manner to
actuate the tumblers and permit the lock bolts to
be operated. 3. That part of a soldering iron
which transfers heat and solder to the joint. 4.
The cutting edge of a plane.

CUTTING
EDGES

bit, 1

bitbrace A brace, 3.

bite In glazing, the distance by which the inner

edge of a frame (or a stop) overlaps the edge of

the glass or panel.
bit gauge, bit stop A metal piece temporarily

fixed to a bit to prevent drilling too deeply in a

blind hole.

ill

bit key

bit key A key having a projecting blade or wing
which engages with and actuates the bolt and
tumblers of a lock.

bit stock A brace, 3.

bit stop See bit gauge.

bitumen A semisolid mixture of complex
hydrocarbons derived from coal or petroleum, as
coal-tar pitch or asphalt; before application, usu-
ally dissolved in a solvent, emulsified, or heated
to a liquid state.

bitumen macadam A macadam in which the
aggregate, of relatively uniform size, has been
coated with bitumen.

bituminized fiber pipe A lightweight drainage
pipe fabricated of cellulose fiber combined with
coal tar.

TAPER

SHOULDER
bituminized fiber pipe

bituminous cement A black substance avail-
able in solid, semisolid, or liquid states at normal
temperatures; composed of mixed indeterminate
hydrocarbons; appreciably soluble only in carbon
disulfide or other volatile liquid hydrocarbon;
esp. used in sealing built-up roofing and between
joints and in cracks of concrete pavements.

bituminous coating An asphalt or tar com-
pound used to provide a protective finish for a
surface.

bituminous concrete See asphaltic concrete.

bituminous distributor A truck equipped with
a tank body and with a system for pumping hot tar,
road oil, or other bituminous material through a
perforated spray bar at the rear; used to lay down a
surface coating of the bituminous material.

bituminous emulsion A suspension of minute
globules of bituminous material in water (or of
minute globules of water in a liquid bitumi-
nous material); used as a protective coating
against weather, esp. where appearance is not
important.

bituminous felt See asphalt prepared roofing.

bituminous grout A mixture of bituminous
material and aggregate such as sand; liquefies
when heated; suitable for pouring in joints or
cracks as a sealant; cures in air.

bituminous hot-mix Any pavement, having
asphalt as the binder, which is laid while hot.

bituminous paint A low-cost paint contain-
ing asphalt or coal tar, a thinner, and drying
oils; used to waterproof concrete and to protect
piping where bleeding of the asphalt is not a
problem.

bituminous varnish A dark-colored varnish
(either of the oil or spirit type) that contains
bituminous ingredients.

bituminous waterproofing A waterproofing
material such as tar.

bivalate, bivallate In military architecture, a
pair of defensive ditches and earth embankments,
usually concentric, that surround a mound or
medieval fort.

BK SH On drawings, abbr. for "book shelves."

BL On drawings, abbr. for building line.

B/L Abbr. for "bill of lading."

B»labeled door A door carrying a certifica-
tion from the Underwriters' Laboratories, Inc.
that it meets the requirements for a class-B
door.

black ash mortar, black mortar A mixture
of high-calcium lime, water, and ashes or clinker
which relies on its pozzolanic properties for its
hard set.

blackbody 1. A body whose radiation at each
wavelength is the maximum possible for any
electromagnetic radiator at that temperature. 2.
A body that absorbs all light which is incident
on it and consequently looks black.

black bolt A hot-formed bolt covered with
black scale, not of uniform diameter; used in
steel construction.

black diapering Same as diaperwork.

black ebony See ebony.

black japan A high-quality bituminous paint
used as a metal varnish.

black light Invisible ultraviolet electromag-
netic energy near the visible spectrum; useful for
exciting fluorescent paints, dyes, etc., so that
they become visible.

112

blast-furnace slag cement

black light fluorescent lamp A fluorescent
lamp whose phosphor is designed to emit black
light.

black locust See locust.

black mortar See black ash mortar.

black steel pipe Uncoated steel pipe, called
"black" because of the dark-colored iron-oxide
scale formed on its surface; usually used for low-
pressure hot-water heating pipes.

blackout switch On a theater stage, a master
switch that extinguishes all stage lights simulta-
neously.

black plate Uncoated cold-rolled steel in
sheets, usually 12 in. (30.5 cm) to 32 in. (81.3
cm) in width.

blacksmith shop A shop where iron bars are
forged into objects such as tools, and where
horses are fitted with horseshoes.

blacktop See asphaltic concrete.

blade l.The flat metal surface of a trowel with
which plaster is applied. 2. The cutting part of a
knife, plane, etc. 3. The broad, slightly concave
surface of a bulldozer, or the like, which pushes
the material being moved. 4. One of the princi-
pal rafters of a roof. 5. To remove, spread, or
level a material such as dirt, or gravel by the use
of a grader.

blade frequency The number of times fan
blades pass a given point per second; equals the
number of blades in the fan multiplied by the fan
speed in revolutions per second.

blader grader Same as grader.

Blaine apparatus An apparatus for mea-
suring the surface area of a finely ground
cement, or the like, on the basis of its air per-
meability.

Blaine fineness The fineness of a powdered
material, such as cement, as determined by the
Blaine apparatus; usually expressed as a surface
area in square centimeters per gram.

Blaine test A test for determining the fineness
of cement, or other fine material, on the basis of
the permeability to air of a sample of the mater-
ial prepared under specified conditions.

blanc fixe A fine-grained barium sulfate, used
as white pigment in paints.

blandel Same as apostilb.

blank arcade Same as blind arcade.

blank door l.A recess in a wall, having the
appearance of a door; usually used for symmetry
of design. 2. A door which has been sealed off
but is still visible.

blanket encumbrance A lien or mortgage
which is applied proportionately to every lot
within a subdivision.

blanket grouting See area grouting.

blanket insulation Thermal insulation, com-
monly fabricated of fibrous glass material, with
or without confining envelope, facings, or coat-
ings; in properly selected density and thickness,
can conform to curved or irregular surfaces of
equipment, large-diameter piping, or tanks; also
used as an acoustical material behind a facing
material or as a component in sound-insulating
construction.

blank flange A flange without bolt holes; oth-
erwise complete.

blank jamb A vertical member of a door-frame
which has not been prepared to receive hardware.

blank wall, blind wall, dead wall A wall
whose whole surface is unbroken by a window,
door, or other opening.

blank window, blind window, false win-
dow l.A recess in an external wall, having
the external appearance of a window. 2. A
window, which has been sealed off but is still
visible.

blast area The area in which the loading of
explosives and the blasting operations take place.

blast cleaning Any cleaning process, such as
sandblasting, in which an abrasive is directed at
the surface with high velocity.

blast freezer An upright freezer in which air, at
a very low temperature, is circulated by blowers;
used to freeze foods in minimum time.

blast-furnace slag The nonmetallic product,
consisting essentially of silicates and alumi-
nosilicates of calcium and other bases, which
is developed in a molten condition simultane-
ously with iron in a blast furnace. The solidi-
fied product is further classified by the process
by which it was brought from the molten
state; also see air-cooled blast-furnace slag,
expanded blast-furnace slag, granulated blast-
furnace slag.

blast-furnace slag cement See portland
blast-furnace slag cement.

113

blast heater

blast heater A heater consisting of a set of
heat-transfer coils (or sections) through which
air is drawn or forced by a fan at relatively high
velocities.

blast hole A hole drilled into rock in which an
explosive charge is to be placed.

blasthole drill A drill which cuts holes in rock
for the placement of explosives.

blasting Using explosives to loosen rock or
other closely packed materials.

blasting agent According to OSHA: a mater-
ial or mixture consisting of a fuel and oxidizer
used for blasting, but not classified as an explo-
sive and in which none of the ingredients is clas-
sified as an explosive, provided the furnished
product cannot be detonated with a No. 8 test
blasting cap when confined.

blasting cap A metallic tube closed at one end,
containing a charge of one or more detonating
compounds, and designed for and capable of det-
onation from the sparks or flame from a safety
fuse inserted and crimped into the open end.

blasting mat A heavy, flexible covering (usu-
ally made of woven- wire rope or cordage); cov-
ers an area during blasting, to prevent rock or
earth fragments from flying about.

blast-resistant door A steel door which has
been fabricated to resist dynamic stresses caused
by blast pressures up to 3,000 lb per sq in. (211
kg per sq cm).

bldg Abbr. for building.

bleachers A grandstand (or section within a
grandstand) where the seats are usually not pro-
vided with backrests.

bleacher seating A stand of tiered planks pro-
viding undivided space for seating.

bleaching A chemical or photochemical reaction
which whitens or removes color from a surface.

bleb A blister or small bubble in a fluid or in a
material (such as glass) that has solidified.

bled timber Wood from trees tapped for resin.
Although appearance may be affected, strength
is usually not.

bleeder A small valve used to drain fluid from a
pipe, radiator, vessel, etc.

bleeder pipe, bleeder tile A pipe, usually of
structural clay, for carrying water from a drainage
tile to a drain or sewer.

bleeding 1. The upward penetration of a color-
ing pigment from a substrate through a topcoat
of paint. 2. The oozing of grout from below a
road-surfacing material to the surface in hot
weather. 3. Exudation of one or more compo-
nents of a sealant, with possible absorption by
adjacent porous surfaces. 4. The autogenous
flow of mixing water within, or its emergence
from, newly placed concrete or mortar; caused
by the settlement of the solid materials within
the mass or by drainage of mixing water; also
called water gain. 5. The diffusion of coloring
matter through a coating from the substrate, or
the discoloration that arises from such a process.

bleeding capacity The ratio of the volume of
water which is released by bleeding, 4 to the vol-
ume of mortar or paste.

bleeding rate The rate at which water is
released by bleeding, 4 from mortar or paste.

bleeding test A test (ASTM C232) for mea-
suring the tendency for water to rise to the sur-
face of freshly placed concrete.

bleed-through, strike-through Discoloration
in the face plies of wood veneer constructions
caused by oozing of glue through the face veneers.

blemish In wood, marble, etc., usually a minor
appearance defect that does not necessarily
affect durability or strength.

blended cement A mixture of portland
cement and other material such as granulated
blast-furnace slag, pozzolan, hydrated lime, etc.,
combined either during or after the finish grind-
ing of the cement at the mill.

blended lamp Same as self-ballasted lamp.

blender A soft round-tipped paintbrush used
for blending colors and smoothing out brush
marks left by coarser brushes.

blending In hot-water systems, the mixing of
hot water with cold water in order to raise the
cold-water temperature. Blending usually takes
place at the point of use.

blending valve A three-way valve which per-
mits liquid entering the valve to be mixed with
liquid that recirculates through the valve; used
to obtain a desired liquid temperature.

blight In plants, a fungus disease causing them
to wither.

blighted area Any area which has become an
economic and aesthetic liability to a community.

114

blind nailing

blind 1 . A device to obstruct vision or keep out
light; usually a shade, a screen, or an assemblage
of light panels or slats. 2. A solid disk inserted in
a pipe joint or union to prevent the flow of water
during the repair of a water distribution system.

blind alley A road, alley, or passageway open at
one end only. Also see cul-de-sac.

blind arcade A decorative row of arches
applied to a wall as a decorative element, esp. in
Romanesque buildings.

blind arcade

blind arch An arch in which the opening is
permanently closed by wall construction.

blind area An area built around the outside of
a basement wall to prohibit penetration of
moisture.

blind attic An attic space, floored but unfin-
ished inside. Also see loft, 1.

blind casing, subcasing A rough window
frame or subcasing to which trim is added.

blind door l.Same as blank door. 2. A lou-
vered door.

blind dovetail Same as secret dovetail.

blind drain A drain which is not connected to
a sewage system.

blind fast A catch for securing a blind or a shut-
ter, in either an open or a closed position.

blind flange A flange which closes the end of
a pipe.

blind floor Same as subfloor.

blind header In an interior of a brick wall, a
header concealed so that it does not appear on
the face of the wall.

blind hoistway A hoistway that does not have
a hoistway door at every floor.

blind hole A hole which is drilled only partway
through the thickness of the material.

blinding 1. A thin layer of lean concrete or of
fine gravel or sand applied to a surface to fill
voids and to provide a smoother, cleaner, drier,
or more durable finish; esp. fine gravel or sand
over freshly placed asphaltic concrete. 2. Sprin-
kling small stone chips over a freshly tarred
road. 3. Placing a material over piping to com-
pletely cover it. 4. Compacting of soil directly
over a drain tile, thereby reducing its tendency
to move into the tile.

blind joint 1. A type of masonry joint in dou-
ble Flemish bond; a thin line joint between two
stretchers (this line bisects a header in the
course directly below). 2. A joint, no part of
which is visible.

blind lancet A blind arch in the shape of a
lancet.

blind mortise, stopped mortise A mortise
whose depth is less than the thickness of the
piece into which it is cut, so that it does not pass
through it.

blind-mortise-and-tenon joint, stub mor-
tise and tenon A joint combining a blind
mortise and a stub tenon; neither is visible in the
assembled joint.

MORTISED
PIECE

TENONED

piece

blind-mortise-and-tenon joint

blind nailing, concealed nailing, secret
nailing 1 . Nailing in such a way that the nail-
heads are not visible on the face of the work. 2.
In finished roofing, the use of nails that are not
exposed to the weather.

Attaa&fe)

blind nailing

115

blind nipple

blind nipple A nipple, one end of which is

capped.

blind pocket A pocket in the ceiling at a win-
dow head to accommodate a Venetian blind
when it is raised.

blind rivet A small-headed pin having an
expandable shank for joining light pieces of
metal.

blind row In an auditorium, a row of seats hav-
ing its first seat at a side aisle and its last seat at a
side wall.

blind seat A seat in an auditorium having
an obstructed or partially obstructed view of
the stage.

blind slat An obliquely-set slat (as in a shutter),
which serves to shed rain but to admit light.

blind stop A rectangular molding used in the
assemblage of a window frame; nailed between
the outside trim and the outside sashes, it serves
as a stop for storm sashes and screens and assists
in preventing air infiltration.

BLIND STOP

blind stop

blindstory l.A floor level without exterior

windows. 2. The triforium of a Gothic church,

or derivatives.
blind tenon A tenon which does not pass all

the way through a mortise.
blind tracery Tracery adorning a wall or panel

but not pierced through.
blind wall A blank wall.
blind window See blank window,
blister 1 . A roughly circular or elongated

unbonded area between plies of laminated con-

structions, as in wood veneer. Usually caused by
entrapped moisture. Also called steam blow. 2. A
spongy raised portion of a roofing membrane,
where separation of the felts has occurred or the
membrane is not bonded to the substrate as a
result of the expansion of water and air trapped
in the membrane. 3. A raised spot on the surface
of the metal caused by expansion of gas in a sub-
surface zone during thermal treatment. 4. A
raised area on the surface of a molded plastic
caused by the pressure of internal gases on its
incompletely hardened surface. 5. See blistering.
6. A convex, raised area on the surface of a pipe
which indicates an internal separation.

blister figure, quilted figure A quilt-like
pattern in wood veneer, usually caused by a
nonuniform grain structure.

blistering 1. Small blisters, bubbles, or bulges in
a plaster finish coat; results from applying a finish
coat over too damp a base coat, or from troweling
on plaster too soon; also called turtleback. 2. See
blister. 3. The irregular raising of a thin layer at
the surface of placed mortar or concrete during or
soon after completion of the finishing operation,
or, in the case of pipe, after spinning. 4. In the fir-
ing of a ceramic, the development of enclosed or
broken macroscopic vesicles or bubbles in a body
or glaze or other coating.

blk 1. Abbr. for "block." 2. Abbr. for "black."

BLKG On drawings, abbr. for blocking.

BLO On drawings, abbr. for blower.

bloated Swollen, as in certain lightweight
aggregates for concrete, as a result of processing.

bloated clay Clay which has expanded during
firing, owing to entrapped air or the breakdown
of sulfides or other ingredients in the clay; light
and porous; suitable for insulating aggregate in
lightweight concrete. Also see expanded clay.

blocage Masonry that is composed of irregularly
shaped stones laid in a mass of mortar.

block l.A masonry unit; a concrete block. 2.
(Brit.) A walling unit which exceeds in length,
width, or height the dimensions specified for a
brick. 3. A solid piece of wood or other material.
4. A plank or timber which serves as bridging
between joists or the like. 5. In quarrying, the
large piece of stone, generally squared, that is
taken from the quarry to the mill for sawing,
slabbing, and further working. 6. A mechanical

116

blocking

block, 6

device which encloses one or more pulleys,
through which chains or ropes pass, usually for
hoisting. 7. A small area of city or town which is
bounded by neighboring and intersecting
streets; the length of a side of such an area. 8.
(Brit.) A large building which is divided into a
number of units, as a block of flats.

block-and-cross bond Same as common-

and-cross bond.
block and tackle A pulley block, 6 together

with rope or cable, used to raise or shift a load.

block beam A flexural structural member,

composed of individual concrete blocks which

are joined together by prestressing.
blockboard See coreboard; strip core.
block bond Same as common bond.
block bonding In joining one part of a brick

wall to another, the use of several courses of

brickwork.

block bridging, solid bridging, solid strut-
ting Short members (boards) which are
fixed vertically between floor joists to stiffen
the joists.

block bridging

block capital Same as cushion capital.

block coin Same as block quoin.

block cornice A cornice used in Italian archi-
tecture; usually consists of a bed molding, a
range of block modillions or corbels, and a
corona or cornice (the bed molding may be
omitted).

block flooring Blocks of wood which are used

as paving or flooring.

blockholing The breaking of boulders by firing
a charge of explosive that has been loaded in a
drill hole.

blockhouse 1 . A fortified structure used to fur-
nish protection against enemy attack in frontier
areas, usually at a location of strategic impor-
tance; often square or polygonal in plan; typi-
cally constructed of hewn timbers having
dovetailed notches at the corners to provide
strong rigid joints; commonly, an overhanging
upper story; often masonry walls on the ground
story with log construction above, or entirely of
log construction; frequently, a pyramidal roof;
usually a few small windows with heavy shutters;
loophole openings through the walls permit the
firing of guns over a wide range of angles. 2. A
reinforced concrete structure that provides shel-
ter against the hazards of heat, blast, or nuclear
radiation.

blockhouse

block»in»course Hammer-dressed stones (which
may vary in length) having square faces, laid
with close joints, in courses not exceeding 12 in.
(30 cm) in height; used in heavy engineering
masonry construction.

block-in-course bond In a brick arch of con-
centric rings which is divided in sections, a bond
within a section formed through the full depth
of the archivolt by a block of bonded brick or by
a voussoir inserted at intervals; ties together the
concentric rings.

blocking 1. Pieces of wood used to secure, join,
or reinforce members, or to fill spaces between
them. 2. A method of bonding two adjoining or
intersecting walls, not built at the same time, by
means of offsets whose vertical dimensions are not
less than 8 in. (20 cm). 3. The sticking together of
two painted surfaces when pressed together. 4. An
undesired adhesion between touching layers of a

117

blocking chisel

material, as occurs under moderate pressure dur-
ing storage or use. 5. Small blocks of wood used
for shimming. 6. Wood which is built into a roof-
ing system above the deck but below the mem-
brane and flashing; used to stiffen the deck around
the opening, to serve as a stop for thermal insula-
tion, and to serve as a nailer for attachment of the
membrane or flashing.

blocking chisel A broad-edged chisel made in a
number of sizes, shapes, and weights; a bolster, 4.

blocking course 1 . A plain finishing course of
masonry directly above a cornice. 2. A string
course.

blocking course A

block insulation A rigid or semirigid slab of

thermal insulation.
block modillion See modillion.

blockout In a concrete structure under con-
struction, a space where concrete is not to be
placed.

block plan A small-scale simplified plan of a
building, indicating its location and surroundings.

block plane A small plane, held in one hand;
the angle of the cutting blade is low (usually about
20°); esp. used to clean up end grain and miters.

LFVER CAP

FINGER
LEVER .REST

. ADJUSTMENT _, > ,_„,
SCREW PLANE IRON

bWtW BEVEL UP

block plane

block quoin A quoin formed by bricks, distin-
guished decora tively from adjacent masonry by a
contrasting appearance or by a projecting pattern.

block tin In plumbing: pure tin.

blockwork 1 . Masonry of concrete block
and mortar. 2. In timber and log construction,
a technique for notching the corners of a
house.

bloom 1 . The formation of a thin film of mate-
rial on the surface of paint causing it to appear
lower in gloss and milky in color. It varies in
composition depending on the nature of the
paint, drying conditions, etc., and may some-
times be removed with a damp cloth. 2. A type
of efflorescence that appears on brickwork. 3.
A discoloration or change in appearance of the
surface of a rubber product (as sulfur bloom and
wax bloom) caused by the migration of a liquid
or solid to the surface. 4. A defect on a freshly
varnished surface, appearing as a cloudy film. 5.
A surface film on glass; usually results from the
deposition of smoke or vapor.

blooming See bloom, 4.

blow l.See throw, 1. 2. The eruption of water
and sand inside a cofferdam, causing flooding.

blowback A characteristic of a safety valve;
the difference between the pressure at which it
opens and the pressure at which it closes auto-
matically, after the excess pressure has been
released.

blow count l.The number of blows required
to drive an object into soil. 2. In soil borings, the
number of blows required to advance a sample
spoon 6 in. (15.2 cm) or 12 in. (30.5 cm). 3. In
pile driving, the number of blows required to
advance the pile 12 in. (30.5 cm) or the number
of blows per unit distance of advance.

blowdown period In an autoclave, the time
taken to reduce the pressure from its maximum
value to atmospheric pressure.

blower A fan, often heavy-duty, used in HVAC
system applications.

blower-coil unit In an HVAC system, a
blower that moves an airstream across cooling
coils, heating coils, and through an air filter.

blow hole l.Same as gas pocket. 2. Same as
bug hole.

blowing l.See popping. 2. The upward move-
ment of soil material at the base of an excava-
tion or cofferdam as a result of groundwater
pressure.

blowlamp

British term for blowtorch.

118

board-and-batten construction

blown asphalt Asphalt that is treated by
blowing air through it at elevated tempera-
ture to give it characteristics desired for certain
special uses such as roofing, pipe coating,
undersealing portland cement concrete pave-
ments, membrane envelopes, and hydraulic
applications.

blown joint, blow joint A plumbing joint in
a lead pipe, formed with the use of a blowtorch.

blown oil A fatty oil that has been oxidized by
blowing air through it while it is hot; sometimes
mixed with mineral oil for use as a lubricant;
used in paints and varnishes because oxidation
increases its drying power and viscosity.

blow-off On a boiler, an outlet to permit the
discharge of accumulated deposits from water.

a tank which receives discharge from a boiler blow-off

blowout Same as blowing, 2.

blowtorch, Brit, blowlamp A small torch
which generates a high-intensity flame; used for
heating soldering irons, burning off paint, etc.

blow-up Localized buckling or shattering of
rigid pavement caused by excessive longitudinal
pressure.

BLR On drawings, abbr. for boiler.

blub A small hole in a mold or plaster cast,
formed by trapped air.

blue asbestos Same as riebeckite asbestos.

blue brick, sewer brick, Staffordshire blue
A brick of high strength whose blue color results
from firing in a kiln in a flame of low oxygen
content.

blued Said of a steel nail surface that has been
heated so that its surface takes on an oxidized
bluish hue.

blue lias lime (Brit.) A hydraulic lime
obtained by burning blue lias limestone. When
mixed with water, it has a set which is not char-
acteristic of regular limes.

blue metal A hard rock, bluish in color, which
is crushed and used in macadam.

blue print A reproduction of a drawing by
means of a contact printing process on light-
sensitive paper, producing a negative image
consisting of white lines on a blue background;
esp. refers to such reproductions of architec-
tural drawings or working drawings used on
construction sites.

blue stain A dark stain in the sapwood of some
species of trees, usually caused by a fungus; it
does not weaken the wood; also called sap stain.

bluestone A hard, fine-grained, commonly
feldspathic and micaceous sandstone or siltstone
of dark greenish to bluish gray color that splits
readily along bedding planes to form thin slabs;
commonly used to pave surfaces for pedestrian
traffic. A variety of flagstone.

blue top A stake which is driven into the ground,
the top of which indicates the grade level.

bluing The addition of a small amount of clean
blue colorant to a white paint to promote the
visual perception of whiteness.

blunt arch An arch rising to a slight point,
struck from two centers within the arch.

blunt arch

blushing A white or grayish cast on high-gloss
paint; results from the precipitation of binder
solids owing to incompatibility with water, oil,
or solvent.

B/M On drawings, abbr. for bill of materials.

b.m. In the lumber industry, abbr. for board
measure.

BM l.On drawings, abbr. for bench mark. 2.
On drawings, abbr. for beam.

board 1. Lumber less than 2 in. (5 cm) thick
and between 4 in. (10 cm) and 12 in. (30 cm)
in width; a board less than 4 in. (10 cm)
wide may be classified as a strip. 2. Short for
switchboard. 3. A box-office ticket board or
seating chart.

board-and-batten construction Wall con-
struction for a timber-framed house in which the

119

board-and-batten door

BOARD

BATTEN
board and batten

exterior covering consists of closely spaced
boards set vertically, with narrow wood strips
covering the joints between the boards.

board-and-batten door Same as battened
door.

board and brace A type of carpentry work
consisting of boards which are grooved along
both edges and have thinner boards fitted
between them.

board butt joint In shotcrete construction, a
joint which is formed by sloping the gunned sur-
face to meet a board laid flat.

boarded door A batten door.

boarded wall An exterior wall of a building of
wood-frame construction having boards com-
monly applied horizontally, although vertically
positioned boards are found occasionally.

board false plate A board atop a wall plate
that carries and distributes the load imposed
on it by structural members supporting the
roof.

board fence A fence constructed of boards
that are spaced horizontally and fastened to
square lumber posts; widely used in the past, but
now usually found only in upscale rural commu-
nities because of its relatively high cost.

board foot A unit of cubic content used in
measuring lumber; equal in volume to an area of
1 square foot having a thickness of 1 inch.

board house l.A house of board-and-batten
construction, board-on-board construction, or
the like. 2. A timber-framed one-room cottage,
sheathed with vertical cypress boards, in Florida
during the late 16th century when it was a Span-
ish colony; had battened doors, a dirt floor, and
a gable roof of thatched palm leaves with a hole

along the ridge as an outlet for smoke from a fire-
place directly below it.

boarding Boards used as sheathing.

boardinghouse A house that rents furnished
rooms and provides meals for boarders in
exchange for the payment of a weekly or
monthly charge; especially used by workers and
transients in mill towns primarily from the 1 8th
to the early 20th centuries.

boarding in The process of nailing boards on
the outer frame of a house, as a facing.

boarding joist A joist to which floor boarding
is nailed.

boarding school A high school or elementary
school which has living accommodations for its
students.

board insulation, insulating board, insula-
tion board Rigid or semirigid thermal insula-
tion having a thickness small in comparison to
other dimensions; density usually about 4 to 16
lb per cu ft (64 to 256 kg per cu m); low struc-
tural strength.

board lath See gypsum lath, wood lath, insula-
tion lath.

board measure A system of measuring lum-
ber: In the US the term board foot is used; in
many countries using the SI system of units, the
term board metre is used.

board metre A unit of cubic content used in
measuring lumber, equal in volume to an area of
1 square metre having a thickness of 25 millime-
ters.

board of trade unit In Britain, a unit of elec-
trical energy consumption equal to 1 kilowatt-
hour.

board-on-board construction Wall con-
struction for a timber-framed house having an
exterior covering consisting of a double layer of
vertical boards of approximately the same width;
usually, the boards in the second layer are placed
so as to cover the joints between the boards in
the first layer.

board rule A measuring device for finding
the number of board feet in a board without
calculation.

board sheathing A sheathing of board, usu-
ally tightly spaced, but some roof constructions
use open spacing between boards.

120

bofb

ROOF
BOARDS

board sheathing

board siding On the exterior walls of a build-
ing, a series of horizontal wood boards that serve
as a finish and as weatherproofing. See siding.

boardwalk A walkway made of boards or
planks, often a promenade along a shore or beach.

boast To dress or shape stone roughly, usually
with a broad chisel.

boasted ashlar A type of ashlar masonry hav-
ing a boasted surface.

boasted work A dressed (usually by hand)
stone surface showing roughly parallel narrow
chisel grooves, not uniform in width and not
carried across the face of the stone.

boaster A flat, steel mason's chisel used in the
dressing of stone.

boasting drawing In designing stonework, a
drawing indicating the general outline within
which a mason can work.

boat dock See scenery wagon.

boathouse A structure for storing boats when
not in use; generally built at the water's edge,
often partly over the water; sometimes has pro-
visions for social activities.

boat scaffold Same as flying scaffold.

boat spike Same as barge spike.

boatswain's chair A seat supported by slings
attached to a suspended rope, designed to accom-
modate one workman in a sitting position.

bob Same as plumb bob.

bobache See bobeche.

bobeche, bobache The collar fitted to a lamp
holder as on a chandelier and from which glass
prisms may be suspended.

BOCA Abbr. for "Building Officials and Code
Administrators."

BOCA National Building Code A
national building code in the United States pre-
pared by the Building Officials and Code
Administrators International. Address: 4051 W.
Flossmoor Road, Country Club Hills, IL 60478.
Also see Uniform Building Code.

bochka In early Russian architecture, a wooden
roof whose peak has the shape of a horizontal
cylinder with the upper side surface extending
into a pointed ridge.

bochka

bodhika In Indian architecture, the capital of a
column.

bodied linseed oil Linseed oil which has been
thickened in viscosity by processing with chem-
icals or heat; the viscosity may vary from raw lin-
seed oil to almost a gel.

bodily injury Physical injury, sickness, or dis-
ease sustained by a person. Also see personal
injury.

body The principal volume of a building, such
as the nave of a church.

body bricks The best quality bricks made in a
kiln.

body coat 1 . In painting, the final coat on a sur-
face. 2. Same as undercoat.

bodying in, bodying up A process in French
polishing for building up the thickness of the
finish by numerous applications of varnish, rub-
bing each one smooth and level.

b of b Abbr. for "back of board."

121

bog

bog Wet, soft, and spongy ground, where the soil
is composed mainly of decayed and decaying
vegetable matter.

bog house A synonym for outhouse.

bogie On a theater stage, a hanger for an over-
head track, from which scenery, flats, or panels
are suspended.

bog plant A plant which lives continuously in
wet soil, but not in stagnant water.

boil A wet run of material at the bottom
of an excavation or under the sheeting of an
excavation.

boiled oil, pale-bodied oil Any oil, but esp.
linseed oil, which has been partially polymerized
by heating at about 500°F (260°C) together
with driers to promote rapid drying.

boiler A closed vessel in which a liquid is
heated or vaporized by the direct application of
heat to the outside of the vessel.

boiler and machinery insurance Insur-
ance specifically written to cover steam boilers
and other pressure-related equipment in a
building.

boiler blow-off Same as blow-off.

boiler blow-off tank A vessel designed to
receive the discharge from a boiler blow-off out-
let where the discharge is cooled to a tempera-
ture low enough to permit its safe entry into the
drainage system.

boiler compound A chemical added to water
in a boiler to prevent corrosion, foaming, or the
formation of boiler scale.

boiler feed valve An automatically-controlled
valve for maintaining a desired amount of water
in a boiler.

boiler horsepower A unit of measurement of
the power of a steam boiler; equivalent to the
evaporation of 34-5 lb of water per hour into dry
saturated steam from and at 212°F.

boiler jacket The covering of thermal insula-
tion around a boiler.

boiler plate 1. Plates of steel used for making
boilers and tanks. 2. The accessories and appur-
tenances associated with a boiler plant. 3. Those
portions of the specifications that commonly
apply to most buildings, so are commonly repro-
duced from one set of specifications to another.

boiler rating The heat capacity of a boiler.

boiler return trap A device used to return
condensate to a low-pressure boiler when it can-
not flow into the boiler by gravity.

boiler room A room in which one or more
steam or hot-water boilers and associated equip-
ment are located.

boiler scale Metal from the inner surfaces of a
boiler which decomposes and flakes off (in much
the same manner as rust forms).

boiler steel A medium-hardness steel which is
rolled into plates 0.25 in. (0.6 cm) to 1.5 in. (3.8
cm) thick; used in fabricating boilers.

boiling Same as blowing, 2.

boiling tub, maturing bin A large tub used
to slake high-calcium or magnesium quicklime
to form a lime putty.

boiserie Wood paneling on interior walls, usu-
ally floor to ceiling; as a rule enriched by carv-
ing, gilding, painting, or, rarely, inlaying. Also
see paneling, wainscot.

bolection molding, balection, belection,
bellexion, bilection, bolexion A mold-
ing projecting beyond the surface of the work
which it decorates, as that covering the joint
between a panel and the surrounding stiles and
rails; often used to conceal a joint where the
joining surfaces are at different levels.

bolection molding

bollard A low single post, or one of a series, usu-
ally stone, set to prevent motor vehicles from
entering an area.

bolster l.A short horizontal timber or steel
member placed on top of a column to sup-
port and decrease the span of beams or girders.
2. One of the rolls forming the sides of an Ionic

bolster, 4

122

bond-beam block

capital, joining the volutes of the front and rear
faces; a baluster or pulvinus. 3. In centering an
arch, a crosspiece which connects the ribs and
supports the voussoirs. 4. A blocking chisel for
masonry work. 5. A horizontal piece of wood or
a timber that caps a column, pillar, or post to pro-
vide greater bearing area for supporting a load
imposed from above; often highly decorative.

bolster 'work A form of rusticated masonry;
courses of masonry which are curved or bow out-
ward like the sides of a cushion, 1.

bolt l.A metallic pin or rod having a head at
one end and an external thread on the other for
screwing up a nut; used for holding members or
parts of members together. 2. A short section cut
from a tree trunk. 3. A short log from which
veneer is peeled.

CARRIAGE BOLT

y u

SOUARE HEAD MACHINE BOLT
bolts, 1

bolt blank, screw blank A bolt having a
fixed head, but no threads or nuts; intended for a
subsequent threading operation.

bolted pressure switch In an electrical
circuit, a type of knife-blade switch having
jaws into which the knife blades fit under heavy
pressure when the switch is closed; this pressure
assures a low-resistance electrical connection.

boltel See bowtell.

bolt head The enlarged shape which is pre-
formed on one end of a bolt to provide a bearing
surface.

bolting mill In days before commercial flour
was readily available, a small building in which
flour was sifted.

bolt shooting See stud shooting.

bolt sleeve In concrete construction, a tube
which surrounds a bolt in a concrete wall to pre-
vent the concrete from sticking to the bolt.

bolt stud Same as stud, 2.
BOM Abbr. for bill of materials.

bombe Swelling out; having a convex shape.

bona fide bid A bid submitted in good faith,
complete and in prescribed form which meets
the conditions of the bidding requirements and
is properly signed by someone legally authorized
to sign such bid.

bond l.A financial guarantee by a surety
company that work will be completed as
described in a contract. Also see bid bond,
completion bond, contract bond, labor and
material payment bond, performance bond,
surety bond. 2. See roofing bond. 3. The adhe-
sive strength that prevents delamination of the
plies of a built-up roofing membrane. 4. The
union of materials by their adhesive or cohe-
sive properties. 5. See bond timber. 6. An
arrangement of masonry units (headers and
stretchers) laid in a pattern that provides a
brick wall with strength, stability, and in some
cases, beauty, depending on the pattern. For
descriptions of various masonry bonds,
see American bond, basket-weave bond, Chi-
nese bond, common bond, Dutch bond, Eng-
lish bond, English Cross bond, English garden
wall bond, Flemish bond, Flemish garden wall
bond, flying bond, header bond, in-and-out
bond, monk bond, raking stretcher bond, rat-
trap bond, rowlock bond, running bond, silver-
lock bond, stack bond, stretcher bond, Sussex
bond, Yorkshire bond. 7. A low-resistance
electric conductor which joins two adjacent
metal parts or structures.

bond area The area of interface between two
elements across which adhesion develops (or
may develop), as between concrete and reinforc-
ing steel.

bond beam A horizontal reinforced concrete
beam used to strengthen a masonry wall so as to
avoid its cracking; the reinforcement often
extends around the perimeter of the wall.

bond-beam block A hollow concrete masonry
unit with portions depressed to form a continu-
ous channel in which reinforcing steel can be

123

bond blister

placed for embedment in grout. A lintel block
sometimes is used as a bond-beam block.

bond blister A blister at the interface between
the coating and core of metal clad products.

bond breaker 1 . A material used to prevent a
sealant from bonding to the bottom of a joint.
2. A material used to prevent adhesion of newly
placed concrete and the substrate. 3. A material
to facilitate independent movement between
two units that would otherwise behave mono-
lithically.

bond coat 1 . A coat of bonding agent or plaster
to provide a bond for succeeding coats of plaster.
2. A coat of primer used as a sealer or to ensure
adhesion of the paint to the surface.

bond course A course of headers or bond-
stones to bond the facing masonry to the back-
ing masonry.

bonded roof A roof which carries a written war-
ranty (usually for a specified period of time) that
protects an owner against damage from leaks or
other problems related to the weather tightness of
the roof.

bonded member A structural member of pre-
stressed concrete in which the tendons are
bonded to the concrete either directly or by
means of grouting.

bonded post tensioning In prestressed con-
crete, grouting the annular spaces around a ten-
don after it is stressed, thereby bonding the
tendon to the concrete.

bonded rubber cushioning A sponge-rubber-
like carpet underlayment that has been adhered
to the carpet backing during its manufacture.

bonded tendon In prestressed concrete, a pre-
stressing tendon which is bonded to the con-
crete either directly or by means of grouting.

bonded terrazzo A terrazzo flooring whose
underbed is poured directly on the structural
floor.

bonded warehouse A warehouse where
materials may be stored before their installation
on a building project if they are not stored at the
job site. The materials are "in bond," that is,
under the legal control of the project's owner.

bonder A masonry unit that bonds; also called
a bondstone.

bonderized Said of a metal surface that has
been phosphate-coated.

bond face That part of the joint face to which

a field-molded sealant is bonded.
bond header In masonry, a bondstone that

extends the full thickness of the wall; also called

a throughstone.

BONO HEADER

bond header

bonding 1 . The connecting together of all the
electrical grounds in a system to eliminate differ-
ences in ground potential between them. 2. The
interconnecting of cable sheaths and sheaths of
adjacent conductors so there is no potential dif-
ference between the metal parts which are
grounded. 3. The connecting of a gas pipe sys-
tem to an acceptable grounding electrode as
specified by the National Electrical Code or
other applicable code.

bonding agent A chemical substance applied
to a suitable substrate to create a bond between
it and a succeeding layer, as between a subsurface
and a terrazzo topping or between a surface and
the plaster that is applied to it.

bonding brick A brick that acts as a bond-
stone.

bonding capacity 1. An indication of a con-
tractor's credit rating. 2. The maximum amount
of money a bonding company will extend in
contract bonds to a building contractor.

bonding compound See dressing compound.

bonding conductor S ame as bonding jumper.

bonding jumper 1. A conductor used to pro-
vide bonding between metal parts of a system. 2.
A reliable conductor which ensures that there is
good electrical conductivity between the metal
parts to which it is connected.

bonding layer A layer of mortar, usually Vs to
Vi in. (3 to 13 mm) thick, which is spread on a

124

bonus clause

moist and prepared, hardened concrete surface
prior to laying fresh concrete.

bonding stone Same as bondstone.
bond length Obsolete term for development
length.

bond plaster, concrete bond plaster A

mill-mixed gypsum plaster containing a small
percentage of lime; just before application it is
mixed with water only and then applied to a
maximum thickness of l A in. (0.6 cm) over pre-
pared concrete surfaces. It serves as the bond
between the concrete and succeeding coats of
gypsum plaster.

bond prevention l.In pretensioned con-
struction, measures taken to prevent selected
tendons from becoming bonded to the concrete
for a predetermined distance from the ends of
flexural members. 2. Measures taken to prevent
adhesion of concrete or mortar to surfaces
against which it is placed.

bondstone, bonder In stone masonry, a stone
usually set with its longest dimension perpendic-
ular to the wall face so as to tie the masonry wall
to its wall backing. A very large bondstone may
be set with its long dimension parallel to the wall
face and still serve as a bonder, provided that its
width is sufficiently large to tie it to the wall
backing.

bond strength l.The resistance to separation
of mortar and concrete from reinforcing steel (or
other materials) with which it is in contact. 2.
All forces that resist separation, such as adhe-
sion, friction due to shrinkage, and longitudinal
shear in the concrete engaged by the bar defor-
mations. 3. The applied unit load in tension,
compression, flexure, peeling, impact, cleavage,
or shear required to break an adhesive assembly,
with failure occurring in or near the plane of the
bond.

bond stress l.The force of adhesion per unit
area of contact between two bonded surfaces,
such as between concrete and a steel reinforc-
ing bar. 2. The shear stress at the surface of a
reinforcing bar which prevents relative move-
ment between the bar and the surrounding
concrete.

bond timber A timber built into a brick or
stone wall in a horizontal position, for the pur-
pose of strengthening it or for tying it together

during construction; serves as a bonding course
and as a means for securing the battening and
bracketing.

bone black See animal black.

bone-dry wood See ovendry wood.

bone house See ossuary.

boning in (Brit.) In surveying, locating and
driving pegs in the ground so that their tops are
in a line marking a desired gradient.

bonnet 1. A chimney cap. 2. A frame of wire
netting over a chimney to prevent the escape of
sparks. 3. Same as bird screen. 4. A cap placed
over a pile to prevent damage to the pile while
it is being driven. 5. The small roof over a bay
window. 6. A covering over an exterior door or
window to provide shelter and/or a decorative
element; also see pent.

bonnet hip tile, cone tile A tile that resem-
bles a woman's bonnet; used to cover the hip on
a hip roof.

bonnet roof A roof having a double slope on
all four sides, the lower slope being less steep
than the upper slope; often extends over an
open-sided raised porch to provide excellent
shade for the house and protection against
rain. Especially found in French Vernacular
architecture.

bonnet roof

bonus-and-penalty clause A provision in
the construction contract for payment of a
bonus to the contractor for completing the
work, 1 prior to a stipulated date, and a charge
against the contractor for failure to complete the
work by such stipulated date.

bonus clause In a construction contract, a
provision that permits a bonus payment, by
the owner to the contractor, for early com-
pletion of construction work or for a saving
in construction costs. Also called a bonus
provision.

125

book matching

book matching, herringbone matching

The assembling of wood veneers from the same
flitch so that successive sheets are alternated
face up and face down. In figured wood, side-by-
side sheets show a symmetrical mirror image
about the joints between adjoining sheets.

book matching

boom 1. A cantilevered or projecting structural
member (such as a beam or spar) which is used
to support, hoist, or move a load. 2. The project-
ing member at the front of a crane or derrick
which is used for this purpose.

boom hoist A hoist which has a spar attached
to a mast; used to lift and move a load.

booster compressor A compressor which dis-
charges into the suction line of another com-
pressor.

booster fan An auxiliary fan which increases
the air pressure in a system; used to provide addi-
tional capability to handle peak exhaust (or sup-
ply) loads in an air-conditioned space such as a
theater lobby; also used to supply air to furnaces.

booster heater An auxiliary water heater which
is installed in the hot-water piping system to pro-
vide additional heat in one part of the system.

booster pump An auxiliary pump which is
used in a piping system to increase or maintain
the pressure in the system.

atst

f*-.tr

■jij*

booster transformer An electric trans-
former used to raise the voltage of an electric
circuit.

boot The flange and metal casing around a pipe
that passes through a roof.

booth 1 . A fixed seating unit in a restaurant or
bar; usually consists of a table between (or par-
tially surrounded by) seats which have high
backs. 2. See lighting booth.

boot lintel A lintel designed to carry a layer of
facing brickwork.

boot scraper A horizontal metal plate set in a
small frame, once located near the front steps of
most buildings; used to scrape dirt or mud from
the bottoms of shoes or boots before entering the
building; common before the advent of paved
streets.

border In a theater, a strip of material which is
stretched horizontally over the top of a stage,
usually on rigging; used to mask the flies, lights,
and other objects of scenery or overhead
machinery.

borderlight A horizontal strip of lights, hung
parallel to the proscenium of a theater; used to
provide general stage illumination.

border stone Same as curbstone.

bore l.The inside diameter of a pipe, valve,

or other fitting. 2. The circular hole made by

boring.
bored latch A latch intended for installation

in a circular hole in a door.
bored lock A lock intended for installation in

a circular hole in a door.

simplified diagram of a water distributor system employing a
booster pump

a door prepared for installation of a bored lock

bored pile Same as cast-in-place pile.

bored 'well A well constructed by boring a
hole in the ground with an auger and installing
a casing.

borehole See boring.

126

bottom arm

boring, borehole A hole drilled in the ground
to obtain soil samples for evaluation and to
obtain information about the strata.

borning room In colonial New England
houses, a small room (adjacent to the warm
kitchen or keeping room) in which babies were
born and sometimes kept during infancy.

boron-loaded concrete High-density con-
crete having a boron-containing admixture or
aggregate to act as a neutron attenuator. Also see
radiation-shielding concrete.

borrow Material taken from one location for
use as fill elsewhere.

borrowed light 1. A frame in an interior parti-
tion which is glazed, thereby permitting light
from one interior space to fall in another. 2. The
light which is transmitted through such glazing.

borrow pit A bank or pit from which earth is
taken for use as fill elsewhere.

bosket A grove; a thicket or small grouping of
trees in a garden, park, or the like.

bosquet Same as bosket.

boss 1. A projecting, usually richly carved orna-
ment placed at the intersection of ribs, groins,
beams, etc., or at the termination of a molding.
2. In masonry, a roughly shaped stone set to pro-
ject for carving in place. 3. To hammer sheet
metal to conform to an irregular surface. 4. A
protuberance on a pipe, fitting, or part designed
to add strength, to facilitate alignment during
assembly, to provide for fastenings, etc.

boss, 1

bossage In masonry, projecting, rough-finished
stone left during construction for carving later in
final decorative form.

bossing The shaping of soft sheet metal, such as
lead, so that it will conform to the surface to
which it is applied; also called dressing.

bossing mallet A mallet used for striking a
metal surface in bossing.

bossing stick A tool used in shaping sheet lead
for a tank lining.

Boston hip, Boston ridge, shingle ridge
finish A style of finishing a shingle, slate, or
tile hip roof; the shingles are laid in two parallel
rows which overlap at the hip; alternate courses
overlap in opposite directions, providing a
weatherproof joint.

Boston hip

bosun's chair A suspended seat for one per-
son, supported by a rope, sometimes used
instead of a scaffold for minor jobs; its height
may be adjusted by a powered winch or block
and tackle.

botanical garden A garden in which a variety
of plants are collected and grown for scientific
study and display; often includes greenhouses for
tropical material.

bothie, bothy 1. A small cottage or hut, espe-
cially in northern England, Scotland, or Ireland.
2. A house for accommodating a number of
workers for the same company, farmer, or
employer.

botress, botrasse Same as buttress.

bottle Old English term for bowtell.

bottle brick A hollow brick which is shaped so
that it may be mechanically interconnected
with similar units; may be laid with steel rein-
forcement.

bottle-nose curb, bottle-nose drip On a
sheet-lead roof, an edge which is rounded to
form a drip.

bottlery A room for the storage of bottled goods
such as beer and ale.

bottom arm The arm mechanism which is
attached to the bottom rail of a door, connecting
it to the spindle of a floor closer or pivot.

127

bottom bolt

bottom bolt A bolt at the bottom of a door;
locks by slipping into a socket in the floor; may
be held in the raised position by a catch.

bottom car clearance The clear vertical dis-
tance from the floor of an elevator pit to the low-
est structural or mechanical part, equipment, or
device installed beneath the elevator car platform
(except for guide shoes or rollers, safety jaw
assemblies, and platform aprons or guards) when
the car rests on its fully compressed buffers.

bottom chord The lower longitudinal member
of a truss.

bottom heave The upward movement of soil
in the base of an especially large excavation.

bottom lateral bracing The lateral bracing
in the plane of the bottom chords of a truss.

bottomless hole A hole which passes com-
pletely through a material.

bottom plate Same as sole plate.

bottom rail 1. The lowest horizontal structural
member of the frame of a door or window that
interconnects its vertical members. 2. The lower
rail in a balustrade.

BOTTOM RAIL

bottom rail: of a do

bottom rail: of a wind o

bottom register A register, 1 located close to the

floor, along a wall.
bottom shore In a series of raking shores

which support a wall, the member that is nearest
the wall face.

bottom stone Same as footing stone.
boudoir See chamber, 1.

boulder A naturally rounded rock fragment
larger than 10 in. (25 cm) in diameter; used
for crude walls and foundations, generally in
mortar.

boulder clay See till.

boulder ditch A French drain.

boulder wall A wall constructed of boulders
set in mortar.

boule A plain-sawn log which has been
reassembled in the original log form, but with
spacers between adjacent slabs.

bouleuterion 1. In ancient Greece, a place of
assembly, esp. for a public body. 2. In modern
Greece, a chamber for the sitting of a legislative
body or the building in which such a chamber is
situated.

boulevard An important thoroughfare, often
with a center divider planted with trees and
grass, or similarly planted dividers between
curbings and sidewalks.

boulevard strip That part of a street's right-of-
way which lies between the street-curb and the
sidewalk.

boultine, boultel See bowtell.
boundary See land boundary.

boundary marker A marker or inscribed
stone that designates some type of boundary; for
example, see meridian stone.

boundary survey A mathematically closed
diagram of the complete peripheral boundary
of a site, reflecting dimensions, compass bearings
and angles. It should bear a licensed land sur-
veyor's signed certification, and may include a
metes and bounds or other written description.

boundary trap Same as intercepting drain.

bouquet The floral or foliated ornament forming
the extreme top of a finial, knob, hip, or the like.

Bourdon gauge A pressure gauge containing a
curved metal tube which tends to straighten
when subject to internal pressure; this movement
is translated into readings on a graduated dial.

bousillage, bouzillage A mixture of clay and
Spanish moss or clay and grass; used as a plaster to
fill the spaces between structural framing; partic-
ularly found in French Vernacular architecture of
Louisiana of the early 1700s. A series of wood bars

128

box-and-strip construction

(barreaux), set between the posts, helped to hold
the plaster in place. Bousillage, molded into
bricks, was also used as infilling between posts;
then called briquette-entre-poteaux. Also see pier-
rotage.

bouteillerie See buttery.

boutel, boutell See bowtell.

bow 1. The longitudinal curvature of a rod, bar,
or piece of tubing or lumber. 2. A flexible rod for
laying large curves to any desired curvature. 3.
Old English term for flying buttress.

Bow

bow, 1

bow compass A compass, one leg of which
carries a pencil or pen; the legs are connected by
a bow-shaped spring instead of a joint; used to
draw arcs or circles.

bow divider A bow compass, each leg of which
terminates in a point; used to transfer measure-
ments from one part of a drawing to another.

bowed roof Same as segmental roof.

bower l.A rustic dwelling, generally of small
scale and picturesque nature. 2. In a large

bower, 3

medieval residence, the private chamber of the
lady. 3. A sheltered recess in a garden.

bowfront A bay window having a semi-circular
or a bowed shape.

bow girder A girder at a "corner" of a building
having a curved facade.

bowl An open-top diffusing glass or plastic
enclosure used to shield a light source from
direct view and to redirect or scatter the light.

bowl capital A plain capital shaped like a bowl.

bowled floor A floor which slopes down-
ward toward a central area, as toward a stage in
a theater.

bowling green A carefully maintained, level
piece of lawn, originally reserved for the game of
bowls (bowling).

bow saw A saw having a narrow blade which is
held taut in a bowed frame.

bow-shaped See double-bellied.

bowstring beam, bowstring girder, bow-
string truss A beam, girder, or truss having
one curved member in the shape of a bow (often
circular or parabolic in shape) and a straight or
cambered member which ties together the two
ends of the bow.

bowstring roof, Belfast roof A roof sup-
ported by bowstring trusses.

bowtell, boltel, boultine, boutell, bowtel,
edge roll l.A plain, convex molding, usu-
ally three-quarters of a circle in section. 2. A
torus or round molding. 3. The shaft of a clus-
tered pillar. 4. A roll molding. 5. A quarter
round or ovolo.

bow window, compass window A rounded
bay window; projects from the face of a wall in a
plan which is the segment of a circle.

box 1 . A private seating area for spectators in an
auditorium, usually located at the front or side of
a mezzanine or balcony; may contain movable,
rather than fixed, chairs. 2. An enclosure for
mounting an electric device and its associated
circuit conductors or for splicing, pulling in, or
terminating conductors.

box-and-strip construction, box construc-
tion A relatively simple, economical wall
construction once used in the United States for
small houses and dependencies; has an exterior
appearance similar to that of board-and-batten

129

box beam

construction. The walls are constructed of
closely-spaced, wide, upright boards, approxi-
mately 1 inch (2.5 cm) thick; the cracks
between the boards are covered with vertical
battens only on the exterior surface of the
boards. The sillplates are secured on a founda-
tion consisting of flat stones.

box beam, box girder A hollow beam, usu-
ally rectangular in section; if fabricated of steel,
the sides are steel plates welded together, or
they may be riveted together by steel angles at
the corners.

box bolt A sliding bolt which is rectangular in
cross section; attached to a door at the edge, it
slides into a receptacle to secure the door.

box casing The inner lining of the cased frame
of a window.

box chisel A chisel, one end of which is
notched; used to pry open boxes that are
nailed.

box column A hollow, built-up column, con-
structed of wood, usually rectangular or square in
section.

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box column

box culvert A culvert, usually of reinforced
concrete, which is rectangular in cross
section.

box dam Same as cofferdam.

box dovetail See common dovetail.

box drain An underground drain which is rec-
tangular in cross section; usually constructed of
concrete or brick.

boxed cornice, box cornice, closed cor-
nice A hollow cornice, built up of boards,
moldings, shingles, etc., so that the lower ends of
the rafters are not visible. Also called a closed
cornice.

box cornice

boxed eaves That part of a roof that projects
beyond the exterior wall (i.e., the eaves), which
is enclosed by boards and/or moldings so that the
rafters are not visible.

boxed frame See cased frame.

boxed gutter Same as box gutter.

boxed heart, boxed pith A timber sawn
so that the heart of the log falls within its
faces.

boxed mullion A hollow mullion which
houses sash counterweights in a window frame;
built up from boards so as to provide a solid
appearance.

boxed pith A piece of lumber cut so as to
enclose the soft central core (i.e., the pith)
within the four faces of the piece.

boxed shutter Same as boxing shutter.

boxed stair Same as box stair.

boxed stringer Same as close string.

box frame l.A structural frame composed of
cells which are side by side and/or in vertical
tiers; the cross-walls act as bearing walls, carry-
ing the loads to the foundation; also called cel-
lular framing or cross-wall construction. 2. A
structural frame having floors and walls consist-
ing of monolithic reinforced-concrete slabs.
3. A cased frame.

box garden A garden divided into sections by
hedges of boxwood.

box girder See box beam.

box gutter A rectangularly shaped wood gutter
that is set into and partially below the lower
edge of a roof; usually lined with sheet lead or
asphalt.

box-head window A window constructed so
that the sashes can slide vertically up into the

130

box stringer

head (or above it) to provide maximum opening
for ventilation.

box house A house having gables on its end
walls; usually two or three rooms wide and two
rooms deep.

boxing 1. A box-like enclosure or recess at the
side of a window frame that receives a boxing
shutter when the shutter is folded and pulled
back. 2. A cased frame. 3. The mixing of paint
by pouring it from one can to another. 4. Con-
tinuing a fillet weld around a corner of a member
as an extension of the principal weld.

boxing, 4

boxing shutter, folding shutter A window
shutter which can be folded into the boxing or

recess at the side.

box lewis Assembly of metal components, some
or all tapered upward, inserted into a downward-
flaring hole (lewis hole) cut into the tops of
columns or other heavy masonry units for hoisting.

box lock A metal door lock commonly encased
in a flat rectangular box, often fabricated of
brass; mounted on the interior surface of a door.

box mullion The built-up mullion of a cased
frame of a double-hung window; has hollow
jambs containing the counterweights.

box nail A nail similar to a common nail but
thinner; has a long shank which may be smooth
or barbed.

box office A room or booth with one or more
windows facing a theater lobby or public area;
used for sale of tickets.

box out To form an opening or pocket in con-
crete by means of a box-like form.

box pew A church pew screened or enclosed by
a high back and sides.

box pile A pile which is fabricated from two
deep-arch sheet piles, steel channels or the like,

and welded along their lines of contact; the
enclosed space may be filled with concrete or
left open.

box scarf A scarf joint used between lengths of
wooden gutter; the reduced end of one length is
fitted into the recessed end of the next, produc-
ing a flush joint which is secured by paint and
screws.

box section Said of a concrete pipe having a
rectangular cross section.

box sill A type of sill, 1 used in frame construc-
tion; a header joist, nailed to the ends of the
floor joists, rests on the sill.

CORNER POST

STUD

STUD-
SOLEPLATE
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SUBFLOOR

HEADER
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sill

box stair, closed stair An interior staircase

constructed with a close string on both sides,

often enclosed by walls or partitions with door

openings at various floor levels.
box stall, loose-box In barns or stables, an

individual compartment in which an animal

may move about freely.
box staple On a doorpost, a socket which

receives the end of a lock bolt which secures the

door.
box stool A stool with a compartment beneath

a hinged lid or seat.
box stoop A high stoop making a quarter turn,

reached by a flight of stairs along a building

front.
box strike plate, box strike A metal plate

on a doorframe into which the bolt of a door

lock projects, and which provides a complete

housing that protects the bolt opening from

tampering.
box stringer Same as a close string.

131

x union

box union Same as union, 1.

box up To encase with boards, as in the nailing

of sheathing boards over studs.
boxwinder A staircase whose entrance is

concealed behind a door next to a fireplace;

sometimes architecturally balanced by a pantry

door on the opposite side of the fireplace; often

found in elegant homes in the 18th and 19th

centuries.
boxwood A fine-grained, very hard, dense

wood, white to light yellow in color; esp. used for

turned work and inlay.
box 'wrench A wrench, usually double-ended,

that has a closed socket which fits over the head

of a bolt or a nut.

BP l.On drawings, abbr. for blueprint. 2. On
drawings, abbr. for baseplate. 3. On drawings,
abbr. for bearing pile.

BPG Abbr. for "beveled plate glass."

BR On drawings, abbr. for bedroom.

bracciale A projecting metal bracket, having a
socket and ring for holding a flagstaff, torch, or
the like; esp. used on Renaissance palaces in
Florence and Siena.

brace 1 . A metal or wood member which is used
to stiffen or support a structure; a strut which
supports or fixes another member in position or
a tie used for the same purpose. 2. An angle
brace. 3. A tool having a handle, crank, and
chuck; used for holding a bit or auger and rotat-
ing it to drill a hole by hand; also called a bit
stock. 4. A raker, 2.

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brace, 3

brace block A block of wood used to lock
in place adjacent layers of a built-up wood beam.

braced Strengthened or well interlaced and
linked together by bracing.

braced arch An openwork truss in the form of
an arch.

braced door See framed door.

braced excavation An excavation whose

perimeter is retained by sheeting.
braced frame, braced framing, full frame

1. The frame of a building in which the resistance
to lateral forces or to frame instability is provided
by diagonal bracing, K-bracing, or other type of
bracing. 2. Heavy, braced wood framing for a
structure which uses girts that are mortised into
solid posts; the posts are full frame height, with
one-story-high studs between, usually diagonally
braced.

braced frame, 1

brace molding The molding formed by join-
ing two ogees with the convex ends together and
in section resembling the brace used as a symbol
in printing. Also see keel molding.

brace piece A mantelpiece.

brace pile See batter pile.

brace table, brace scale, brace measure
A table indicating the length of hypotenuses for
right isosceles triangles with legs of various
lengths; used by carpenters in cutting wood
braces to length.

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132

bracketing

bracing 1. Structural elements installed to pro-
vide restraint or support (or both) to other mem-
bers, so that the complete assembly forms a
stable structure; may consist of knee braces,
cables, rods, struts, ties, shores, diaphragms, rigid
frames, etc., singly or in combination. 2. Collec-
tively, the braces so used.

brack See cull.

bracket l.Any overhanging member project-
ing from a wall or other body to support a
weight (such as a cornice) acting outside
the wall. 2. A knee brace which connects
a post or batter brace to an overhead strut.
3. A projecting electrical wall fitting. 4. A short
board attached to the carrying member on the
underside of a stair supporting the tread.
5. A decorative detail attached to the spring of a
stair under the overhanging edge of the treads.
Also see eaves bracket, stair bracket, step
bracket, wall bracket.

bracket, 1

bracket baluster A metal baluster whose base
is bent at right angles and built into the string of
a masonry stair.

bracket capital l.A capital extended by
brackets, lessening the clear span between posts,
often seen in Near Eastern, Muslim, Indian, and
some Spanish architecture. 2. Same as bolster, 1.

bracketed cornice A deep cornice supported
by a series of decorative brackets, often in pairs.

bracketed eaves See eaves bracket.

bracketed hood A projecting surface over a
window or door that is supported by brackets;
provides some shelter or serves as ornamenta-
tion.

bracketed stair A flight of open string stairs;
one with decorative brackets on the exposed
outer string and under the return nosing of
treads.

cottage with bracketed eaves

bracketed hood above a door

bracketed stair

bracketed string An open string having,
secured to its face, bracket-shaped pieces which
appear to support the overlapping treads.

bracketed style A term occasionally used for
the Italianate style.

bracketing l.Any system of brackets. 2. An
arrangement of wooden brackets employed as a

133

bracket pile

skeleton support to plasterwork, moldings, or
other plaster ornamental details.

bracket pile One of a series of piles which are
driven into the ground adjacent to a foundation
to support it; brackets, which are welded to the
piles, and which extend under the foundation,
transfer the structural load from the foundation to
the piles.

bracket saw A handsaw used for cutting
curved shapes.

bracket scaffold, bracket staging A scaf-
fold which is supported by metal brackets which
are attached to the building.

bracket valve A stop valve whose body incor-
porates a supporting bracket for piping which it
controls.

brad 1 . A small finishing nail, usually of the same
thickness throughout, with a head that is almost
flush with the sides or a head that projects slightly
to one side. 2. A tapering, square -bodied finishing
nail with a countersunk head.

eras

brad, 1

brad awl A small awl used to make starter holes
for brads or screws.

brad punch, brad set A nail set for small fin-
ishing nails or brads.

brad pusher A tool used to hold and insert a
brad into the surface of wood in an inaccessible
location.

brad set, brad setter See brad punch.

bragger A corbel.

braided 'wire An electrical conductor which is
composed of many fine wires braided or twisted
together.

braid pattern Same as guilloche.

braie In Medieval architecture, an outer enceinte,
2 consisting of a palisade or low masonry wall on
the counterscarp of a ditch.

brake horse power (bhp) The useful
mechanical power supplied by an engine as
determined by a friction brake or an absorption
dynamometer that is applied to the shaft or fly-
wheel of the engine.

branch In plumbing, a pipe which originates in
or discharges into a main, submain, riser, or stack.

branch cell A plumbing fitting in a line which

is at an angle to the main pipeline, usually at a

right angle.
branch circuit The portion of an electric wiring

system that extends beyond the final overcurrent

device (such as a fuse) protecting the circuit.
branch conductor In a lightning protection

system, a conductor that branches off at an angle

from a continuous run of the conductor.
branch drain A drain pipe connecting the soil

line or plumbing fixtures in a building to the

main line.
branch duct An air duct which branches from

a main duct; at this point the main duct is

reduced in cross-sectional area.

branch duct

BRANCH DUCT

AIR TERMINAL
DEVICE

branch duct: installation

branch fitting A fitting used to connect one or
more branch pipes to a main pipe.

branch interval A length of soil stack or waste
stack which is usually one story high, but not less
than 8 ft (2.4 m), within which the horizontal
branches from one story of a building are con-
nected to a stack.

branch joint l.A joint taken off a main
pipeline. 2. The wiped joint used where one pipe
branches from another.

134

brcg

branch knot A knot in wood formed as a result
of two or more branches originating from the
same point.

branch line 1 . A water supply line which connects
one or more fixtures with the main supply, with a
riser, or with another branch. 2. A pipe in which
fire sprinklers (i.e., sprinkler heads) are placed.

branch pipe A length of pipe which has one or
more branches.

branch rib Same as Heme rib.

branch sewer A sewer that receives sewage
from a relatively small area.

branch tracery A form of Gothic tracery in
Germany in late 15th and early 16th cent.; made
to imitate rustic work with boughs and knots.

branch vent 1 . A vent connecting one or
more individual vents with a vent stack or stack
vent. 2. A vent pipe to which are connected
two or more pipes that vent plumbing fixtures.

brass, 2

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branch vent, 1

brander To apply furring.
brandering See cross-furring.
brandishing Same as brattishing.

brandrith A fence or rail around the opening
of a well.

brashy, short-grained Descriptive of weak,
brittle wood that has little resistance to shock or
bending and usually breaks quite abruptly.

brass l.Any copper alloy having zinc as the
principal alloying element, but often with small
quantities of other elements. 2. A plate of brass
with memorial inscription and sometimes an
effigy engraved on it, set into a church floor to
mark a tomb.

brass pipe Pipe manufactured from an alloy
containing 85 percent copper and 15 percent

zinc. The advantages and disadvantages of brass
pipe are similar to those for copper tubing,
except that brass pipe can be used in a drain pipe
under pressure and that the joints between brass
pipes can be screwed or soldered.

brattice, bretesse, breteche In medieval for-
tifications, a tower or bay of timber construction.
(See illustration p . 136.)

brattishing, brandishing, bretisement A

decorative cresting at the top of a Gothic screen,
panel, parapet, or cornice, generally in the form
of openwork of a stylized floral design.

braze To join two pieces of metal by a hard, non-
ferrous filler metal, usually in rod or wire form,
having a melting temperature above 800°F
(427°C).

brazed joint A gastight and watertight metal-
pipe joint formed by brazing; often used in cop-
per piping systems.

brazier A receptacle containing burning coal or
coke; sometimes used to dry out a building.

Brazilian rosewood, palisander A varie-
gated, hard, heavy wood having shades of brown
and violet or red with black streaks; used for
turned articles and decorative paneling.

brazing solder Same as hard solder.

brc Abbr. for brace.

brcg Abbr. for bracing.

135

BRE

brattice

BRE In Britain, abbr. for Building Research
Establishment; formerly called the Building
Research Station (BRS).

breached Said of a building contract when one
or more parties has failed to perform in accor-
dance with the exact terms of the contract.

bread room In medieval times, a room fitted
with shelves for loaves of bread and biscuits, and
bins for flour and confectionery; was part of the
buttery.

break A change in direction of a plane; usually
in reference to a wall.

breakaway wall A wall that is not part of the
structural support of a building to which it is
attached; deliberately intended (through its
design and construction) to collapse under spe-
cific lateral loading forces without causing dam-
age to the elevated portion of the building or to
the supporting foundation system.

breakdown voltage The voltage at which an
electrical insulation ruptures, thereby destroy-
ing its insulating value and permitting current
flow.

breaker A rock-crushing machine in which
small particles are produced by impact or by frac-
ture between movable jaws.

breaker ball, headache ball A heavy,
rounded metal weight which is swung from a
crane line; used to demolish masonry or con-
crete structures.

breakfast nook A nook where light meals are
taken; usually has a built-in table and seating.

break-glass call-point A British term for a
fire alarm box.

break-in In bricklaying, a cutout in a brick wall,
to form an aperture for the insertion of a timber.

breaking down, conversion The process of
sawing logs into boards.

breaking ground Initial excavation work,
indicating the start of construction.

breaking joints Any arrangement of structural
units, esp. masonry units, such that the vertical
joints between adjacent units do not follow a
vertical line, but are staggered.

breaking load, failure load, fracture load,
ultimate load The load which, if placed
upon a structure or test piece, is just great
enough to break it.

breaking radius The minimum radius of cur-
vature that a piece of wood (or plywood) can be
bent without breaking.

breaking strength Same as ultimate strength.

breaking stress The stress at which a compo-
nent ruptures under a tensile force.

break tank A water tank system that incorpo-
rates an air gap in it to prevent water from back-
ing into the system and contaminating the
potable water supply.

break-out The transfer of acoustic energy from
the interior of an HVAC duct, through the duct
walls, to the space surrounding the duct.

breast l.A projecting part of a wall, as at a
chimney. 2. That portion of a wall between the
floor and a window above. 3. The underside of a
handrail, beam, rafter, or the like.

breast beam See breastsummer.

breast board One of a number of boards used
to retain the face of an excavation.

breast drill A hand-operated drill having a
piece against which the chest is braced to provide
additional force.

136

brick

breast drill

breast lining The interior wooden paneling
between a windowsill and the baseboard
below.

breast molding l.The molding on a window
sill or on the breast of a wall. 2. Paneling
beneath a window.

breastsummer, breast beam, bressummer,
brestsummer A horizontal beam which
spans a wide opening (a lintel) in an external
wall; a summer, 3.

breast timber Same as wale.

breast wall, face wall 1. A retaining wall. 2.
A parapet which is breast high.

breastwork 1. Masonry work for a chimney
breast. 2. The parapet of a building. 3. A defen-
sive wall, hastily constructed, about breast high,
often protecting the summit of a mound.

breathe The property of a layer of a material
that permits air and/or moisture to pass through
it without damaging the layer.

breather membrane See breather-type asphalt
felt.

breather-type asphalt felt An underlay-
ment sheet material, saturated with asphalt,
which permits the transmission of water vapor;
often used as underlayment for asbestos-cement
shingles.

breccia Any stone composed of angular frag-
ments embedded and consolidated in a finer
ground. Numerous marbles owe their distinctive
appearance to brecciation.

breech fitting See breeching fitting.

breeching l.The duct or pipe connecting the
exhaust-gas discharge from a boiler furnace, or
other fuel-burning equipment, to a stack. 2. A
breeching fitting.

breeching fitting, breech fitting, breeching
A Y-shaped symmetrical pipe fitting in which the
flow in two parallel pipes is united in one pipe.

breeze See pan breeze.

breeze block A concrete masonry unit using
pan breeze as aggregate.

breeze brick Brick made from pan breeze and
Portland cement; often built into ordinary
brickwork because of its good nail-holding
capability.

breezeway A covered passageway, open to the
outdoors, connecting two cabins, two parts of a
house, or between a house and a garage; some-
times serves as an outdoor sitting area; also
called a dogtrot.

bressummer See breastsummer.

brestsummer See breastsummer.

bretesse See brattice.

bretisement Same as brattishing.

BRG On drawings, abbr. for bearing.

brick A solid masonry unit, usually of clay,
molded into a rectangular shape while plastic, and
then treated in a kiln at an elevated temperature
to harden it, so as to give it mechanical strength
and to provide it with resistance to moisture; after
being removed from the kiln, the brick is said to be
burnt, hard-burnt, kiln-burnt, fired, or hard-fired.
Bricks laid lengthwise in a wall are called stretch-
ers; bricks laid crosswise to a wall are called head-
ers. Bricks differ in color, ranging from dark red to
rose and salmon, and from pink to blue-black and
purple, depending on the type of clay and on the
temperature of the kiln in which they were burnt.
Various types of patterns common in laying bricks
are described under bond. The current American
brick is typically about 8 inches (20.3 cm) long, 3%
inches (8.26 cm) wide, and 2K inches (5.7 cm)
thick; other countries tend to produce bricks with
their own standard dimensions. For specific types
of brick, see adobe quemado, air brick, angle
brick, arch brick, axed brick, brindled brick,
building brick, bull stretcher, burnt brick, cant
brick, capping brick, closer, common brick, com-
pass brick, concrete brick, coping brick, cow-nose
brick, dogleg brick, dog-tooth course, Dutch

137

brick anchor

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brick: nomenclature

brick, engineered brick, engineering brick, fire-
brick, fired brick, flooring brick, gauged brick,
glass brick, glazed brick, hard-burnt brick, hollow
brick, kiln-fired brick, molded brick, mortar, mud
brick, pug-mill brick, pressed brick, radius brick,
rough-axed brick, rubbed brick, rustic brick,
sailor, salmon brick, sand-faced brick, sand-lime
brick, semiengineering brick, soft brick, soldier,
solid brick, standard brick, stock brick, twin brick,
unburnt brick, vitrified brick, wire-cut brick. See
bond for a description of brickwork patterns. Also
see adobe for a description of sun-dried brick.

brick anchor A device made of deformed
metal stripping, designed to be embedded in the
structural concrete of a building to support brick
or other veneer facing material.

brick and brick A method of laying brick so
that units touch each other; mortar is used only
to fill surface irregularities.

brick-and-half wall A brick wall whose
thickness equals one header plus one stretcher.

brick-and-stud work See brick nogging.

brick ashlar In a wall, an ashlar facing and a
brick backing.

brick ax Same as brick hammer.

brickbat A bat, 1.

brick beam A lintel formed by several courses
of bricks and held together by iron straps.

brick bond Same as bond, 6.
brick cement A waterproof cement used in
masonry work.

brick core The rough brickwork that fills the
space between a timber lintel and soffit of a dis-
charging arch.

brick earth A loamy impure clay used for
brickmaking.

brick face That surface of a brick which is
intended for use as the exposed surface of a
masonry structure.

brick facing See brick veneer.

brick filling In half-timbered construction,
brick laid between the heavy structural timbers
to provide thermal insulation, fire resistance,
and increased structural rigidity.

brick gauge A standard height of brick courses,
e.g., four courses in a height of 12 in. (30 cm).

brick grade ASTM designations for the dura-
bility of brick: SW (severe weathering), MW
(moderate weathering), or NW (negligible
weathering).

brick hammer, bricklayer's hammer A
steel tool, one end of which has a flat square sur-
face used as a hammer, for breaking bricks, dri-
ving nails, etc.; the other end forms a chisel peen
used for dressing bricks.

brick hammer

bricking up Filling up door or window open-
ings with brick.

brick insert Same as concrete insert, but
placed in a brick wall.

bricklayer's hammer See brick hammer.

bricklayer's square scaffold A scaffold com-
posed of framed wood squares which support a
platform; limited to light and medium duty.

138

brickwork movement joint

bricklaying Laying brick and filling all joints,
as well as cleaning, grouting and pointing, and
waterproofing.

brick ledge On a wall, a ledge that supports a
course of masonry.

brick masonry See brickwork.

brick molding A wood molding used to cover
the gap between a door or window frame and the
masonry reveal into which the frame is set.

brick nogging, brick-and-stud work Brick-
work laid in the spaces between timbers in a
wood-frame wall; also see nogging.

brick on bed A brick in an ordinary brick wall,
all courses of which are laid on the largest side.

brick on edge A brick laid on its narrow edge.

brick oven See bake oven.

brick paver See paver.

brick seat A ledge on a footing or wall which
supports a course of masonry.

brick set A bolster for cutting brick.

brick slip A solid tile, either cut from one face
of a brick or specifically manufactured to similar
dimensions; usually about 1 in. (2.5 cm) thick.
Used to simulate brickwork construction either
for prefabrication or in facing in situ concrete
members.

brick tile A tile with one of its faces molded so
that it appears to be the face or end of a brick.

brick trimmer A brick arch abutting against the
wood trimming joist in front of a fireplace, used to
support the hearth; a trimmer arch of brick.

brick trowel A trowel having a flat, triangle-
shaped steel blade in an offset handle used to pick
up and spread mortar. The narrow end of the blade
is called the "point"; the wide end, the "heel."

brick trowel

brick tumbling See tumbling course.

brick type ASTM designations for the chippage
tolerance and distortion of brick: for solid brick:
BBS, FBX, and FBA; for hollow brick: HB, HBX,
and HBB.

brick veneer, brick facing A facing of brick
laid against the front side of an exterior wall but
not bonded to it; provides a decorative, durable
wall surface. Such bricks typically are laid
lengthwise, so this type of construction is rela-
tively thin, economical, and easy to lay.

SHEATHING
PAPER

FLASHING

brick veneer

brickwork, brick masonry Masonry of brick
and mortar. Also see skintled brickwork, rein-
forced-grouted brick masonry, rendered brick-
work.

brickwork column An isolated vertical load-
bearing member whose width is not more than
four times its thickness.

brickwork cube A cube of brickwork, 9 in.,
(22.86 cm) on each side, used widely for quality
control tests in Great Britain for load-bearing
brickwork constructions.

brickwork movement joint A j oint designed
to permit relative movement between a brick wall
and its adjacent structure without impairing the
functional integrity of the structure.

139

bridal cable

bridal cable An anchor cable which is perpen-
dicular to the line of pull.

bridal hitch The connection between a bridle
cable and a pulley block or sheave block.

bridge 1. A structure that spans a depression or
provides a passage between two points which are
at a height above the ground affording a passage
for pedestrians, vehicles, etc. 2. At a demolition
or construction site, a scaffold built over the
adjacent sidewalk to protect pedestrians and
motor vehicles from falling material or debris. 3.
In the backstage of a theater, a platform or
gallery (of fixed or adjustable height), over or
alongside the stage; used by scene painters (see
paint bridge), lighting operators (see light
bridge), and stagehands.

bridgeboard A notched board that supports
the treads and risers of wooden stairs.

bridge crane A traveling overhead hoisting
machine which spans fixed side rails that are
part of a building structure or are erected to sup-
port the crane; the hoisting unit also may travel
laterally between the rails; used to handle mate-
rials in such a location as a machine shop or fab-
ricating plant.

bridged floor A floor using common joists for
support.

bridged gutter A gutter formed by boards
which are supported on a beam and are covered
with lead sheeting or other suitable material.

bridge joint In carpentry, see bridle joint, 1.

bridge lighting system A low- voltage, two-
wire cable lighting system.

bridge-over Said of a member (such as a joist)
which is laid across parallel lines of support.

bridge stone A flat stone providing passage

over a gutter or areaway.
bridgewall A low firebrick separating wall in a

furnace.
bridging A brace, or a system of braces, placed

between joists (or the like) to stiffen them, to hold

them in place, and to help distribute the load.
bridging floor A floor supported by common

joists, without girders.
bridging joist Same as common joist.
bridging piece A wooden member fastened

between or across floor joists to stiffen them or

to carry a partition.

BRIDGING

bridging

bridle iron Same as hanger, 2.

bridle joint In carpentry: 1. A joint formed by
two timbers, of which one is hollowed out to
receive the end of the other (with recessed
sides). 2. A joint in which two tongues project
from the sides of the tenoned member; these
tongues fit into corresponding slots in the mor-
tised member.

bridle joint, 1

bridle path, riding trail A path, cleared and

compacted, reserved for riding horses and barred

to vehicles.
Briggs standard See American standard pipe

threads.
bright Descriptive of freshly cut lumber or

veneer which is not discolored.
bright dip A dip used to give a bright surface to

brasses; often a mixture of sulfuric acid, nitric

acid, hydrochloric acid, and water.

140

British thermal unit

bright glaze A colorless or colored ceramic

glaze having high gloss.
brightness That attribute of visual perception

in accordance with which a surface appears

to emit more light or less light. Now called

luminance,
brightness meter A common expression for a

luminance meter.
brilliance The clarity, strength, and brightness

of a color or varnish.
brindled brick Brick having a brown mottled

surface; sometimes used as facing brick.
brine In a refrigeration system, any liquid used

as a heat transfer medium which remains as a

liquid and which has either a flashpoint above

150°F (66°C) or no flashpoint; usually a water

solution of inorganic salts.

Brinell hardness A measure of resistance of a
material to indentation; obtained by use of a
machine which presses a standard hard steel or
carbide ball into the material, under standard
loading conditions; expressed by the Brinell
hardness number — the higher the number, the
harder the material.

PRESSURE
GAGE

Brinell hardness tester

Brinell hardness number A measure of
Brinell hardness; obtained by dividing the load
expressed in kilograms (applied to a ball, usually

10 mm in diameter), by the area of indentation,
expressed in square millimeters.

briquette, briquet A molded specimen of mor-
tar with enlarged extremities and reduced center
having a cross section of definite area, used for the
measurement of tensile strength of mortar.

briquette-en-poteaux In French Vernacular
architecture of Louisiana, vertical wood framing
having brick infilling.

briquette-entre-poteaux In French Vernacu-
lar architecture of Louisiana, a relatively inexpen-
sive, porous brick that was once used to fill the
spaces between upright posts and diagonal braces
in a home of timber-framed construction; often
found in poteaux-en-terre houses; usually the
entire brick-filled exterior surface was finished
with a coat of lime plaster to protect the surface;
then often covered with clapboard. Many two-
story town houses and houses of well-to-do planters
had basement walls of brick and upper walls of bri-
quette-entre-poteaux. Also see bousillage.

brisance The crushing or shattering effect of a
high explosive.

brise-soleil A fixed or movable device, such as
fins or louvers, designed to block the direct
entrance of sun rays into a building.

bristle brush A brush made with animal hair
(usually from hogs) or with synthetic fibers.

Bristol glaze A raw ceramic glaze containing
zinc oxide, often used in terra-cotta.

British Board of Agrement An indepen-
dent British organization, which operates under
government sanction, for testing, assessing, and
issuing certificates concerning the performance
of new building materials (or old materials used
in new ways), components, products, and/or
building systems.

British Standard, British Standard specifi-
cation A specification of grades, qualities,
sizes, etc., of materials, components, etc., pub-
lished by the British Standards Institution.

British Standards Institution A national
organization (corresponding to the American
National Standards Institute and the American
Society for Testing Materials) which establishes
and publishes standard specifications.

British thermal unit The amount of heat
required to raise the temperature of 1 pound of
water by 1 degree Fahrenheit. Abbr. Btu.

141

brittle

brittle 1. Descriptive of a material which frac-
tures under low stress without appreciable defor-
mation. 2. Descriptive of a paint film unable to
withstand stretching or scratching without
breaking or becoming otherwise deformed.

brittle fracture Said of a fracture that takes
place with no prior ductile deformation.

brittleheart Decayed or brittle wood at the
center of a log.

BRK On drawings, abbr. for brick.

BRKT On drawings, abbr. for bracket.

brl Abbr. for barrel.

broach l.In quarrying, to free stone blocks
from the ledge by cutting out the webbing
between holes drilled close together in a row.
2. To finish a stone surface with broad diagonal
parallel grooves cut by a pointed chisel. 3. A half
pyramid above the corners of a square tower to
provide a transition to an octagonal spire. 4. A
spire sometimes springing from a tower without
an intermediate parapet. 5. Any pointed orna-
mental structure.

broached post Same as king post.

broached spire Same as broach, 1.

broached spire

broached work See broach, 2.
broach post Same as king post.

broach stop See chamfer.

broadax An ax having a large, broad blade;
used for the roughdressing of timber.

broad glass Same as cylinder glass.

broad knife, stripping knife A knife with a
square-edged, wedge-shaped blade for removing
paint or wallpaper; similar to a putty knife but
with a wider blade.

broad-leaf tree See hardwood.

broadloom Seamless carpet of any weave,
woven on a wide loom, usually 6 to 18 ft (1.8 to
5.5 m) wide.

broad stone Same as ashlar.

broad tool A wide steel chisel used to finish-
dress stone.

broad tooled See batted work.

brob A wedge-shaped spike used to secure the
end of a timber which butts against the side of
another.

broch A prehistoric circular stone tower found
along the western coastline of Scotland.

broken arch A form of segmental arch in which
the center of the arch is omitted and is replaced
by a decorative feature; usually applied to a wall
above the entablature over a door or window.

broken ashlar See random work, 2.

broken-color work Same as antiquing.

broken edge An edge of a metal sheet con-
taining cracks, splits, or tears.

broken-flight stair Same as dogleg stair.

broken gable A vertical surface at the end of a
building having a broken-pitch roof; extends from
the level of the cornice to the ridge of the roof. It
is not triangularly shaped, as in the case of a roof
having a single pitch on each side of the ridge.

broken joints Vertical masonry joints which
are staggered to provide better bond and added
structural strength, no unit being directly above
another.

broken-joint tile A curved roof tile which
overlaps only the tile in the course immediately
below.

broken pediment 1. A pediment whose slop-
ing or curving sides terminate before reaching
the pediment's highest point, resulting in an
opening that is often filled with an urn, car-
touche, or other ornament; sometimes called
an open pediment or broken-apex pediment.

142

brownstone

broken pediment

2. A pediment with sloping or curving sides

whose base is broken in the middle; also called a

broken-base pediment.
broken-pitch roof A roof having more than

one pitch on each side of a central ridge.
broken rangework Stone masonry laid in

horizontal courses of different heights, any one

course of which may be broken (at intervals)

into two or more courses.

■; '-'i^y -!■:■" T"

w^w^--

broken rangework

broken-scroll pediment Same as swan's-
neck pediment.

broken-stripe veneer A variation of ribbon-
stripe veneer in which the stripes are intermit-
tent; produced by interwoven grain which is
quarter-cut.

broken white A toned-down white paint, usu-
ally cream-colored.

bronteum In ancient Greek and Roman the-
aters, a device for producing the noise of thunder,
generated by the impact of stones against the
inside of a heavy vase designed for this purpose.

bronze l.An alloy of copper and tin. 2. Any
alloy, bronze in color, having a substantial
admixture of copper to modify the properties of
the principal element, as aluminum bronze,
magnesium bronze, etc.

bronze glass Glass, having the color of bronze,
which reflects incident solar energy, thereby
reducing the transmission of energy through it;
often useful in controlling glare.

bronzing 1 . A form of chalking on a paint film,
caused by weathering; appears varicolored when

viewed at different angles. 2. The application of
a coating of metal bronze powder.

broom l.To press a layer of roofing material
against bitumen which has just been applied, in
order to achieve proper and complete bond
between the roofing plies. 2. To brush the
scratch coat of plaster with a broom to improve
the mechanical adhesion of the brown coat, thus
producing a broom finish. 3. To spread the head
of a timber pile by impact.

broom finish l.The surface texture obtained
by stroking a broom over freshly spread concrete
or plaster. 2. See broom, 2.

brooming See broom, 2.

brotch A thin piece of a tree branch which is
bent in a U-shape; used for fastening thatch on
roofs; also called a buckle or spar.

Brown and Sharpe gauge See American
wire gauge.

brown coat, floating coat The coat of
roughly finished plaster beneath the finish coat;
in three-coat work, the second coat of plaster,
applied over a scratch coat and covered by the
finish coat; in two-coat work, the base-coat
plaster applied over lath or masonry; may con-
tain a greater proportion of aggregate than the
scratch coat.

brown-glazed brick See salt-glazed brick.

browning Same as brown coat.

brownmillerite A mineral compound occur-
ring in portland cement and high-alumina
cement; consists of an oxide of calcium, alu-
minum, and iron.

brownout 1 . To complete the application of a
base-coat plaster. 2. The setting of base-coat
plaster, which darkens, or browns, as it sets.
3. The dimming of lights as a consequence
of a reduction of voltage furnished to a section
of a city (or an entire city) by the electrical
utility.

brown rot A fungus that destroys wood cellu-
lose, leaving a brown powdery residue behind.

brown stain A chocolate brown stain produced
by fungus in the sapwood of some pine trees.

brownstone 1. A dark brown or reddish brown
arkosic sandstone, quarried and used extensively
for building in the eastern US during the middle
and late nineteenth cent. 2. A dwelling faced
with brownstone, often a row house.

143

browpiece

browpiece A beam over a door; a breastsummer.
brow post Same as crossbeam.

browsing room A section of a library reserved
for users to examine and casually read a collec-
tion of books, magazines, or documents.

BRS On drawings, abbr. for brass.

Br Std Abbr. for British Standard.

Brunswick black A type of bituminous paint.

Brunswick blue See Prussian blue.

Brunswick green, lead chrome green A
light green powder; a pigment consisting of lead
chromate and iron blue pigments.

brush 1. An implement made of natural or arti-
ficial bristles which are attached to a handle or
back; used for cleaning or painting a surface. 2.
An electric conductor (such as a strip of copper or
a carbon rod) which provides electrical contact
between a rotating and stationary element in a
current motor or generator.

HEEL

FERRULE
■HANDLE

FLAG END OF BRISTLES"
brush, 1

brushability The property of a paint or varnish
which enables it to be applied smoothly by
brushing.

brushed finish A surface finish on stonework,
produced by treating the surface with a rotating
wire brush.

brushed surface Said of a concrete surface
that has been stroked with a stiff brush when the
concrete is freshly placed or slightly hardened.

brush finish, brushed finish A finish pro-
duced by a rotating wire brush.

brush graining An imitation effect of wood
grain; produced by drawing a clean dry brush
through a dark liquid stain, applied over a dry,
light base coat.

brush mark A small ridge or valley produced
in a paint film by the combing action of the bris-
tles of a brush.

brushout The application of paint on a small
surface for testing.

brush rake An attachment with heavy-duty
tines, which is fixed to the front of a tractor or
other prime mover; used in land clearing to
gather and pile debris.

Brussels carpet l.A carpet made of several
colors of worsted yarn, fixed in backing of strong
linen thread; the pile forms a pattern of uncut
loops. 2. An inexpensive, single-colored substi-
tute for the above.

Brutalism, New Brutalism A style of mod-
ern architecture, primarily in the 1960s, empha-
sizing heavy, monumental, stark concrete forms
and raw surfaces; may show patterns of the rough
wood formwork used in casting the concrete
(beton brut). Buildings in this style are often sug-
gestive of massive sculptures.

BRZ On drawings, abbr. for bronze.

BRZG On drawings, abbr. for "brazing."

BS 1. Abbr. for "British Standard" published by
the British Standards Institution; each standard
is designated by the letters BS followed by a
number. 2. On drawings, abbr. for "both sides."
3. Abbr. for "beam spacer."

BSCP Abbr. for "British Standard Code of
Practice."

BSI 1. Abbr. for British Standards Institution. 2.
Abbr. for "Building Stone Institute."

BSMT On drawings, abbr. for basement.

BSR Abbr. for "building space requirements."

BSS Abbr. for "British Standard Specification."

bstd Abbr. for "bastard."

BTB Abbr. for "bituminous treated base."

Btr., btr In the lumber industry, abbr. for "better."

Btu Abbr. for British thermal unit.

bubble glass Glass in which decorative bub-
bles have been introduced during manufacture.

bubbling Bubbles of entrapped air or solvent
vapors which protrude from a paint surface;
formed either on application or during drying of
the paint film.

bubile A structure to house cows.

bubinga, African rosewood A west African
wood, light red to violet in color, often with pur-
ple stripes, frequently figured; hard, high den-
sity; used as interior finish and for decorative
paneling.

buck l.A door buck. 2. A sawhorse.

144

buffer

bucket An attachment for a materials-handling
or excavating machine that digs or carries loose
materials such as earth, gravel, stone, or concrete;
may be shaped like a scoop, with provision for
opening and closing for convenience in unloading.

bucket loader See chain-bucket loader and
tractor loader.

bucket sink A plumbing fixture whose basin is
located near the floor so that it provides easy
access to a water supply and drain.

bucket trap A mechanical, buoyancy-operated
steam trap which is designed to prevent steam
from passing through the trap; makes use of an
inverted or upright cup.

bucket-wheel excavator An excavating
machine having a rotating wheel fitted with
toothed-edged buckets; used to dig a layer of
earth and load it onto a conveyor belt as the
machine moves forward under its own power.

buck frame, core frame A wood frame
which is built into a partition, constructed on
wood studs, to receive a door lining; a subframe.

bucking Sawing felled trees into logs.

buckle 1 . Distortion of the surfaces of a beam or
girder under load; caused by unequal distribution
of weight, temperature, or moisture, or the lack
of uniform texture. 2. Distortion of the surface of
a sheet of material, such as a bulge or wrinkle in
asphalt prepared roofing. 3. A brotch.

buckler An ornament used in the decoration of
friezes; sometimes circular or lozenge-shaped.

buckler

buckling load The load, 1 under which a
structural member distorts under compression.

buckling load, Brit, crippling load The
axial load at which a perfectly straight column or
structural member starts to bend.

buck opening A rough opening.

bucksaw A saw consisting of a blade set in an
H-shaped frame; used for cutting wood on a
sawhorse.

buck scraper A type of earth scraper; when
filled, the scoop is raised from the ground by run-
ners on each side.

buckstay l.A vertical member, usually in
cross-connected pairs, reinforcing the side walls
of an arched masonry furnace or flue to take the
thrust of an arch. 2. Any similar brace member.

bucranium, bucrane A sculptured ornament
representing the head or skull of an ox, often
garlanded; frequently used on Roman Ionic and
Corinthian friezes.

bucranium

buckling The collapse of a slender vertical ele-
ment which has been subjected to compression,
leading to a sudden sideways deflection.

bud 1. To graft a plant by inserting a bud of one
plant into the stock of another. 2. An element in
a Corinthian capital. (See illustration p. 146.)

bud capital Same as lotus capital.

buff l.To clean and polish a surface so that a
high luster results. 2. To grind down and/or pol-
ish a floor finish of terrazzo or other exposed-
aggregate concrete.

Buffalo box See curb box.

buffer l.A device, apparatus, or material
which reduces mechanical shock due to impact.
2. A device located at the bottom of an elevator
hoistway, designed to stop a car or counter-
weight from descending beyond its normal limit
of travel; motion beyond this limit is taken up
by storing or by absorbing and dissipating the
kinetic energy of the car or counterweight. Also
see oil buffer, spring buffer. 3. Any type of bar-
rier that limits the scattering of rock as a result

145

bud, 2

of blasting. 4. A material that absorbs moisture
from the atmosphere and then releases it when
the surrounding air becomes drier. 5. Landscap-
ing used to block a view, fully or in part. 6. The
zone around a water source or wetland designed
to protect the water's features. 7. An area adja-
cent to a stream, shoreline, or wetland where
development is restricted.

buffer yard 1. Landscaping that is used to
obstruct the view of an adjacent property. 2.
Same as buffer, 5.

buggy, concrete cart A two-wheeled or four-
wheeled cart, often motor-driven, usually rub-
ber-tired, for transporting small quantities of
concrete from hoppers or mixers to forms.

bug holes Small regular or irregular cavities,
usually not exceeding Vs in. (15 mm) in diame-
ter, resulting from entrapment of air bubbles in
the surface of formed concrete during placing
and compaction.

bugle Same as reducer, 2.

buildable land area The total land area that
is available for improvement, excluding private
or public rights-of-way.

builder The individual or firm who is the
employer of craftsman required for erecting a

building in accordance with the plans and spec-
ifications prepared by the architect and who car-
ries the responsibility for doing so.

builders' doorway Same as barrow hole.

builders' guide, builders' handbook, buil-
ders' manual See pattern book.

builders' hardware See finish hardware.

builder's jack A bracket attached to a win-
dowsill, which projects outside the window; used
to support a scaffold.

builder's level l.A level, 1 which is set in a
long wood or alloy frame. 2. A simple type of tilt-
ing level or dumpy level.

builder's lift A hoist, 1 used to lift workers and
materials to upper stories of a structure during its
construction.

builder's risk insurance A specialized form of
property insurance to cover work, 1 in the course
of construction. Also see property insurance.

builders' shed style Same as Shed style.

builder's staging A heavy scaffold which is
constructed of square timbers, braced together;
usually used for the handling of heavy materials.

builder's tape A tape measure; in the US, usu-
ally 50 ft or 100 ft long, contained in a circular
case.

builder's trench A trench that is dug to seat the
foundation of a building during its construction.

building A more or less enclosed and perma-
nent structure for housing, commerce, industry,
etc., distinguished from mobile structures and
those not intended for occupancy. Also see
accessory building.

building alteration See alteration.

building area The total area of a site which is
covered by buildings as measured on a horizon-
tal plane at ground level. Terraces and uncov-
ered porches usually are excluded from this
total, although the stipulations of a mortgage
lender or governmental program may require
their inclusion.

building artifact An element in a building
which demonstrates human workmanship, such
as a stained-glass window.

building block A rectangular masonry unit,
other than a brick, made of burnt clay, cement,
concrete, glass, gypsum, or any other material
suitable for use in building construction.

146

building environment

building board Any sheet of building mater-
ial, often faced with paper or vinyl; suitable for
use as a finished surface on walls, ceilings, etc.

building brick, common brick Brick for

building purposes, not esp. treated for texture
or color.

building classification The designation of a
building according to its use or occupancy.

building code A collection of rules and regu-
lations adopted by authorities having appropri-
ate jurisdiction to control the design and
construction of buildings, alteration, repair,
quality of materials, use and occupancy, and
related factors of buildings within their jurisdic-
tion; contains minimum architectural, struc-
tural, and mechanical standards for sanitation,
public health, welfare, safety, and the provision
of light and air. Also see Uniform Building Code
and BOCA National Building Code.

building code division See division.

building combined drain A building drain

which conveys both sewage and storm water.

building combined sewer A building sewer

which conveys both sewage and storm water.

building component l.A building element
which uses industrial products that are manufac-
tured as independent units capable of being
joined with other elements. 2. According to the
NEC, any subsystem, subassembly, or other sys-
tem designed for use in (or integral with) a struc-
ture or part of a structure, which can include
electrical, fire protection, mechanical, plumb-
ing, and structural systems and other systems
affecting health and safety.

building conservation The management of a
building to prevent its decay, destruction, misuse,

or neglect; may include the recording of the his-
tory of the building and conservation measures
applied.

building construction The fabrication and
erection of a building by assembling or combin-
ing building components, subsystems, or systems.

building construction joint See construc-
tion joint, 2.

building contract See contract documents.

building contract certificate A written
document, appropriately signed by the responsi-
ble parties, testifying to matters of fact in accor-
dance with a requirement of the contract
documents.

building core Same as core, 10.

building coverage The fraction or percent-
age of a site's total area which is taken up by
buildings.

building cover area Same as the footprint of
a building.

building drain That part of the lowest piping
of a drainage system which receives the dis-
charge from soil pipes, waste pipes, and other
drainage pipes inside the walls of the building
and conveys the discharge by gravity to the
building sewer outside the building wall.

building-drainage system All piping pro-
vided for carrying waste water, sewage, or other
drainage from the building to the street sewer or
place of disposal.

building envelope See envelope, 1.

building environment The combination of
conditions that may influence, modify, or other-
wise affect a person, piece of equipment, or sys-
tem in a building (for example, lighting, noise,
temperature, relative humidity, and/or odors).

SEWER PIPE

ADAPTER

30= ^^rj"

building drain

DRAINS

m nc

BUILDING
DRAIN '

CLEANOUT
GRADE

147

building element

building element An architectural component
of a building, facility, or site.

building foundation See foundation, 1.

building frame The structural framing system
of a building having an essentially complete
space frame that supports vertical loads.

building grade The ground elevation, which
is established by the appropriate authority, regu-
lating the height of a building.

building gravity drainage system A
building-drainage system which drains by grav-
ity into the building sewer.

building gross area See gross floor area.

building heat-loss factor A measure of the
rate of heat loss of a building; expressed in Btu per
degree day (joules per degree day). The number of
degree days is multiplied by this factor to obtain
the heat energy requirements during that period.

building height The vertical distance mea-
sured from curb or grade level to the highest
level of a flat or mansard roof, or to the average
height of a pitched, gabled, hip, or gambrel roof;
in general, bulkheads, penthouses, etc., are
excluded provided they are relatively low and do
not occupy a large percentage of the area of the
roof upon which they are located.

building house-drain A house sewer within a
building that conveys sewage in combination
with storm water and other clear-water wastes.

building house sewer That part of the piping
of a drainage system that extends from the end of
the building drain of a house to a public sewer,
private sewer, an individual sewage disposal sys-
tem, or another point of disposal. See building
sewer.

building improvement See improvement.

building inspector A member of a building
department, usually of a municipality, who
inspects construction to determine if it conforms
to both the requirement of the building code and
the approved plans; one who inspects occupied
buildings for violations of the building code.

building insulation See thermal insulation.

building lime, finish lime, mason's lime

Lime used in plastering or masonry work.

building line A line established by law or
agreement usually parallel to a property line,
beyond which a structure may not extend. This

restriction generally does not apply to uncovered
entrance platforms, terraces, and steps.

building main The water-supply pipe, includ-
ing fittings and accessories, from the water main
or other source of supply to the first branch of
the water-distributing system.

building maintenance The actions of ensur-
ing that a building remains in working condition
by preserving it from deterioration, decline, or
failure.

building maisonette See maisonette.

building management system A comput-
erized system for controlling a building's envi-
ronment, including its air-conditioning system,
lighting system, security system, and controls for
the building's overall management of energy
usage. Also see intelligent building.

building material Any material used in con-
struction, such as steel, concrete, brick, masonry,
glass, wood, etc.

building official An official designated by the
appointing authority, whatever his official title,
to enforce the provisions of the applicable build-
ing code and other applicable laws.

Building Officials and Code Administra-
tors International See BOCA National
Building Code.

building ordinances See building code and
building regulations.

building paper A heavy, relatively cheap,
durable paper, such as asphalt paper, used in
building construction, esp. in frame construc-
tion, to improve thermal insulation and weather
protection and to act as a vapor barrier. Special
types are: sheathing paper, used between sheath-
ing and siding; floor lining paper, used between
rough and finish floors.

building permit A written authorization to
an applicant (usually a builder) for a specific
project allowing him to proceed with con-
struction; granted by the municipal agency
having jurisdiction after plans have been filed
and reviewed favorably.

building plan Same as plan, 1.

building preservation The process of apply-
ing measures to maintain and sustain the exist-
ing materials, integrity, and form of a building,
including its structure and building artifacts.

148

building survey

building protection The application of mea-
sures designed to preserve a building and its con-
tents from deterioration, damage (from fire,
water, etc.) and unauthorized intrusion.

building reconstruction The reproduction
by new construction following the exact form
and details of a no longer existing building or
artifact as it once appeared.

building regulations British term for build-
ing code.

building rehabilitation The returning of a
building to a useful state by repair, alteration,
and modification.

Building Research Establishment A gov-
ernment-financed building research organiza-
tion in Britain.

building restoration The accurate reestab-
lishment of the form and details of a building,
its artifacts, and the site on which it is located,
usually as it appeared at a particular time; may
require the removal of later work or the recon-
struction of earlier work which had been
removed.

building restriction Any one of a number of
restrictions, imposed on the construction of a
building or the use of land; may be included in a
code or in other documents, e.g., a restrictive
covenant; may be statutory or contractual.

building restriction line A line, defined by
local ordinances, beyond which structures may
not be erected; usually parallel to the street line.

building retrofit The addition of new building
materials, building elements, and components
not provided in the original construction.

building sanitary drain See sanitary drain.

building sanitary sewer A building sewer
which conveys sewage but does not convey
storm water.

building section Any portion of a building,
such as a room, floor, or floors, that is within the
limits of fire divisions.

building service chute A vertical or inclined
tube or channel that conveys and controls the
fall of objects such as mail, laundry, and garbage
to a lower level.

building services The utilities and services
supplied and distributed within a building gen-
erally related to the building environment,
including: heating, air-conditioning, lighting,

water supply services, drainage services, electri-
cal supply, gas supply, fire protection, and secu-
rity protection.

building sewer That part of the horizontal
piping of a drainage system which extends
beyond the ends of the building drain and
receives the discharge of the building drain and
conveys it to a public sewer, private sewer, indi-
vidual sewage disposal system, or other point of
disposal.

building site See site.

building society One of a number of organiza-
tions in Britain that finance the purchase of a
home in exchange for the purchaser's down pay-
ment cost, plus interest; often backed by an
insurance company.

building space The overall space within a

building envelope.
building standards See building code.

building stone Any stone which may be used
in building construction: granite, limestone,
marble, etc.

building storm drain A building drain that
conveys only storm water.

building storm sewer l.A building sewer

which conveys only storm water. 2. The hori-
zontal piping of a storm drainage system which
extends from the building storm drain, receives
its discharge, and conveys it to the public storm
sewer or other point of disposal.

building subdrain That portion of a building
drainage system which does not drain by gravity
into a building sewer; wastes from the subdrain
are collected in a sump and discharged by a pump.

building subhouse drain Same as building
subdrain.

building subsystem l.A complete group of
elements or set of parts that form and function as
a unit within a finished building. 2. An assem-
blage of components that perform a specific
function in a building, e.g., an air-conditioning
system consisting of its components such as a
fan, ductwork, air diffusers, and controls.

building subsystems Same as building ser-
vices.

building survey A detailed report of the pre-
sent condition of a building, including its
appearance and structural integrity; for example,

149

building surveyor

may include illustrations of the facade and other
walls, and analyses such as the condition of the
masonry.

building surveyor British term for an individ-
ual who has received special training in various
aspects of building construction such as: plan-
ning of construction projects, building construc-
tion techniques, construction costs, and the
legal aspects of building construction. There is
no direct counterpart for this position in the US
Also see Chartered Building Surveyor.

building system 1 . According to the NEC:
plans, specifications, and documentation for a
system of manufactured building or for a type of
system of building components, including varia-
tions thereof as are specifically permitted by reg-
ulation, and which variations are submitted as
part of the building system or amendment
thereto. 2. An assembly of integrated building
subsystems satisfying the functional require-
ments of a building. Also see closed building
system, industrialized building system, open
building system.

building tile See structural clay tile.

building trades Specialized skills connected
with building construction, such as carpentry,
masonry, plumbing, plastering.

building transportation services See verti-
cal transportation services.

building trap, main trap A running trap on
the outlet side of a building drain (on the sewer
side of all drain connections); prevents the pas-
sage of odors between the common sewer and
the plumbing of the building.

Clconoutl

Vent

Inlet

*> Outlet

Fresh-Air Tee
Also Used As
re si Tee

building trap

building unit A unit (such as a building brick
or a structural clay tile), the specifications
for which include measures of its durability,
strength, and other structural characteristics, but
not the specifications related to its appearance.

building volume See above-grade building

volume.
build out Same as fit out.

build up To apply successive layers to form a

thicker mass.
built-up plate Plates that are applied in multiple

layers and then joined to form a thicker plate.

built beam Same as built-up beam.

built environment The aggregate of the
physical surroundings and conditions con-
structed by human beings, in contrast to those
surroundings and conditions resulting from the
natural environment.

built-in Built as an integral part of a larger con-
struction, as furniture which is especially fitted
in a building.

built-on-the-job Fabricated completely on
the jobsite, as joinery fabricated from lumber of
standard sizes.

built rib Same as built-up rib.

built-up 1. Assembled by fastening a number of
parts together. 2. Fabricated of several layers,
thicknesses, or pieces which are laminated or
fastened together.

built-up air casing A field-fabricated enclo-
sure around an air-handling system, usually built
on a waterproof concrete base which has a curb
around it with floor drains, or built on a floor
which is sloped toward drainpipe openings.

built-up beam 1. A beam made of structural
metal units (such as plates and angles) which are
riveted, bolted, or welded together. 2. A beam of
precast concrete units which are joined by shear
connectors. 3. A flitch beam. 4. A timber made
up of several pieces fastened together, forming
one of larger dimensions.

built-up beam on a post

built-up fan equipment A term applied to
an HVAC system in which the fan is selected as
an individual component and integrated in the

150

bulking

installation with other separate elements of the
system such as coils, air filters, and control
dampers for regulating the proportioning of out-
side, exhaust, and return air.

built-up girder Same as built-up beam.

built-up rib A rib made of laminations of tim-
ber of various sizes.

built-up roofing, composition roofing, felt-
and-gravel roofing, gravel roofing A
continuous roof covering made up of laminations
or plies of saturated or coated roofing felts, alter-
nated with layers of asphalt or coal-tar pitch and
surfaced with a layer of gravel or slag in a heavy
coat of asphalt or coal-tar pitch or finished with
a cap sheet; generally used on flat or low-pitched
roofs. Also see tar-and-gravel roofing.

ROOF
SHEATHING

SATURATED
FELT

MOP COAT •
GRAVEL STOP -

GRAVEL

built-up roofing

built-up string A curved stair string formed of
wood members fastened together by counter
cramps.

built-up timber Same as built-up beam, 4.

bulb In lighting, see lamp bulb, light bulb.

bulb angle An angle iron, one side of which
thickens toward the edge, forming a bulbous rib.

bulb shape See lampbulb.

bulb tee A tee, 3 the web of which thickens
toward the edge, forming a bulbous rib.

bulk cement Cement which is transported
and delivered in bulk (usually in specially con-
structed vehicles) instead of in bags.

bulk density The weight of a material (includ-
ing solid particles and any contained water) per
unit volume including voids.

bulk excavation The process of excavating
and then moving the excavated material to
another location.

bulkhead 1 . A structure on the roof of a build-
ing covering a water tank, shaft, or service
equipment. 2. A structure, as on a roof, cover-
ing a stairwell or other opening, to provide ade-
quate headroom. 3. A retaining structure to
prevent earth movement into a dredged area. 4.
A horizontal or inclined door giving access from
the outside of a house to a cellar or to a shaft. 5.
The member of an entrance frame which forms
a base for a sidelight adjacent to a door. 6. In a
concrete form, a partition which blocks fresh
concrete from one section of the form or closes
the end of the form (as at a construction joint).

bulkhead

FLANGE^/V*^
bulb angle

bulb bar A steel or iron bar, one side of which
thickens toward an edge, forming a bulbous rib
at that edge.

bulb of pressure Same as pressure bulb.

bulb pile A pedestal pile.

bulkhead luminaire A lighting fixture, usu-
ally ceiling-mounted, which has a heavy glass
bowl, often enclosed by a wire mesh to protect
the light bulb within from damage; used for tem-
porary illumination around a job site.

bulkhead packer A refuse compactor in
which the refuse is compacted within the unit
itself, into a specific volume, in one or more
bags.

bulking The increase in the bulk volume of a
quantity of a material in a moist condition over

151

bulking factor

the volume of the same quantity dry; also called
moisture expansion.

bulking factor The ratio of the volume of
moist sand to the volume of the sand when dry.

bulking value A measure of the specific grav-
ity of a pigment, usually expressed as gallons per
100 lb or liters per kilogram.

bulk modulus of elasticity, modulus of
volume elasticity A number expressing a
material's resistance to elastic changes in vol-
ume; the ratio between a pressure that acts on a
material (to change its volume) and the frac-
tional change in volume so produced, within the
elastic limit of the material.

bulk oxygen system An assembly of equip-
ment (such as oxygen storage containers,
pressure regulators, safety devices, vaporizers,
manifolds, and interconnecting piping) for sup-
plying a regulated flow of oxygen to a pipeline,
as at a hospital; the oxygen may be stored as a
liquid or gas in either stationary or portable
containers.

bulk specific gravity The ratio of (a) the

mass of a volume of material (including the mass
of the water within the voids, but excluding the
voids between particles) at a stated temperature
to (b) the mass of an equal volume of distilled
water at a stated temperature.

bulk strain, volume strain The ratio of the
change in volume of a body to its original vol-
ume, as a result of stress applied to the body.

bulk strength The mechanical strength per
unit volume of a solid.

bulla A circular metal boss used by the ancient
Romans as a decoration for fastening parts of
doors; often highly ornamented.

bull clam A bulldozer having a curved bowl or

bucket attached to the front of the blade.
bulldog clip Same as a sleeper clip.
bulldog plate See toothed plate.

bulldozer A tractor or other prime mover
equipped with a blade attached by arms or
brackets to its front end; used in pushing or pil-
ing earth or rock.

bulldozer

bullet catch Same as ball catch.

bulletin board A surface used for the display of
announcements, information, and the like, usu-
ally attached with thumbtacks.

bulletproof glass See bullet-resisting glass.

bullet-resisting glass A laminated assembly
consisting of four or more sheets of glass
stacked alternately with layers of a transparent
plastic resin, then bonded under heat and
pressure.

bull float A tool or machine used to smooth
unformed surfaces of freshly placed concrete.

bull float

bulla

bull header, bull head l.In masonry, a
header with one corner rounded; used as a quoin

152

bull stretcher

in brick window sills and at doorways. 2. A
header which is laid on edge so that the end of
the masonry unit is exposed.
bullhead tee, bullheaded tee l.In plumb-
ing, a pipe tee which is connected to a branch
that is longer than the main run. 2. A plumbing
tee which has an outlet larger than the opening
on the run.

4*r-

■

bull-nosed step

bullhead tee, 2

bullion Same as bull's eye.

bullnose, bull's-nose 1 . A blunt or curved out-
side corner, as the corner made by two walls. 2. A
structural member or trim having a rounded edge,
as on stair treads, window sills, doors, etc. 3. In
plastering, a metal bead used on exterior corners
where rounded edges are required. 4. A small,
hand-held carpenter's plane with the cutting edge
set near the front of the grip.

bullnose block A brick or concrete masonry
unit having one or more rounded exterior
corners.

bullnose block

bullnosed plane See bullnose, 4.

bull-nosed step A step, usually lowest in a
flight, having one or both ends rounded to a
semicircle and projecting beyond the face of
the stair string or strings. The semicircular pro-
jection extends beyond and around the newel
post.

bullnose stretcher See bull stretcher.

bullnose trim Same as bullnose, 2.

bull-point A pointed steel hand drill, which is
struck with a hammer; used to chip off small
pieces of masonry or rock.

bull's-eye 1. A figure or ornament of concen-
tric bands. 2. A round or oval aperture, open,
louvered, or glazed; an oculus or oeil-de-boeuf.
3. The enclosure of such an aperture, a double-
arched frame with two or four key voussoirs. 4.
A circular aperture in a masonry wall; usually
formed by voussoirs or tapered bricks.

' SllfWlfl

bull's-eye, 2

bull's-eye window l.A glazed round aper-
ture, glazed with thickened concentric circles of
glass; same as glazed bull's-eye, 2; also called an
oculus, oxeye window, or oeil-de-boeuf. 2. An
aperture similar to 1., but unglazed; may be open
or louvered.

bull's head Same as bucranium.

bull stretcher, bullnose stretcher l.In
masonry, a stretcher having a bullnose along the
longest dimension for laying along an edge, as

153

bulwark

BULL HEADER

BULL STRETCHER

bull stretcher, 2 and bull header, 2

along a sill. 2. Any stretcher which is laid on
edge to show its broad face.

bulwark A strong defensive wall structure, gen-
erally low enough to permit defensive fire.

bumper 1 . A device (other than an oil buffer or
spring buffer) designed to stop an elevator car or
counterweight from descending beyond its nor-
mal limit of travel; the car strikes the bumper,
which absorbs the impact. 2. On a doorframe, a
rubber silencer to reduce noise caused by the
slamming of a door.

bumper bar See guard bar.

bumper guard See guard bar.

bund A continuous, low wall or embankment
along a body of water.

bundled bars A group of parallel reinforcing
bars (not exceeding four in number) in contact
with each other, enclosed in stirrups or ties; used
as reinforcement in reinforced concrete.

bundled tubes Closely-spaced columns that
are interconnected and used as a building's outer
wall, foraiing a strong structural system.

bundle of lath A quantity of lath for plaster-
ing, etc. Usually, wood strips: 50 pieces, Vie in. by
VA in. by 48 in. (0.16 cm by 3.81 cm by 121.9
cm); gypsum lath: 6 sheets, 16 in. by 48 in. (40.6
cm by 121.9 cm).

bundle pier A Gothic pier in which the plan
takes a continuous undulating and breaking out-
line, giving the appearance of a dense bundle of
rising forms rather than the distinct shafts of the
compound pier.

bungaloid house A house similar in charac-
teristics to a bungalow, but having two stories.

bungalow A small one-story or one-and-a-
half-story house, usually having a low profile and
of wood-frame construction, often having a
porch. Although found elsewhere, such houses

were relatively low in cost in the early 20th cen-
tury in America because they could be built
according to plans taken from available pattern
books, or could be purchased as early as 1908 as
precut boards and timbers ready for assembly.
Sometimes called a bungaloid-style house. Also
see prefabricated house.

bungalow court A group of three or more
detached, one-story, single-family dwellings,
arranged with common utilities and accessories
under a common ownership.

bungalow sash The upper sash of a double-
hung window that has been divided by muntins
into a number of long vertical panes; the lower
sash is undivided.

bungalow siding Clapboarding having a min-
imal width of 8 in. (20 cm).

bunk A built-in, usually narrow, bed.

bunker 1. A compartmented bin, often elevated,
for storage of aggregates, sand, coal, etc. 2. A space
in a refrigerator for ice or a cooling element.

bunker fill roof In adobe construction of the
American Southwest, a flat roof supported by
roof beams of heavy logs stripped of their bark;
wood sheathing is laid on the roof beams, which
is then covered with building paper, earth fill,
then a second layer of building paper, asphalt,
and gravel.

buon fresco See fresco.

buoyant foundation A foundation of rein-
forced concrete whose weight, together with
that of the imposed loads, is approximately equal
to the weight of the displaced soil and/or water.

buoyant uplift The force of water or liquefied
soil that tends to lift a building's foundation out
of the ground.

burden 1. Earthy material, rock, etc., which
overlays bedrock. 2. In blasting, the distance
between the blasting charge and the free face of
the material to be blasted.

burglar alarm system An electronic system
designed to detect unauthorized entry into or
within a premise. The system may be activated by
the closure of a switch (for example, by stepping
on a mat, opening a window, etc.), by the inter-
ruption of a photoelectric beam, or by a motion
detector.

burglar bond A decorative masonry pattern of
headers that project beyond the face of a wall.

154

bush-hammered concrete

burh 1 . The communal fortification of an ancient
Anglo-Saxon village. 2. A borough.

buried cable An underground cable which is
installed so that it cannot be removed without
disturbing the soil.

buried plate electrode A plate of iron,
steel, or nonferrous material, at least 0.06 inch
(1.5 mm) thick which has a surface area of
at least 2 square feet (0.2 m 2 ) which is buried
in exterior soil; usually used where conditions
do not permit the driving of a ground rod into
the soil.

burl 1 . An abnormal growth or protuberance on
a tree. Also called knur, knurl. 2. Wood veneer
cut from burls.

burlap, Brit, hessian canvas A coarse
woven fabric of jute, hemp, or, less commonly,
flax, for use as a water-retaining covering in cur-
ing concrete surfaces or as a reinforcement in
plaster.

Burlingtonian style See Anglo-Palladianism.

burned joint A joint formed by fitting the end
of one lead pipe into the flared end of another
lead pipe. Heat is then applied evenly around
the perimeter, melting the overlapping edges
and fusing them together.

burner That part of a furnace, boiler, etc.,
where the flame is produced.

burning The flame cutting of metal plates to a
desired shape.

burning-brand test A fire test of roof cover-
ings in which specified burning wooden brands
are fastened to a sloping roof deck test specimen
while exposed to a specified wind; one of three
fire tests usually applied to roof coverings. Also
see intermittent-flame-exposure test.

burning off Heat-softening an age-dried paint
film by use of an acetylene torch or blowtorch to
permit its removal by scraping.

burning rate A measure of the tendency of
plastics to burn at given temperatures. Certain
plastics, such as those based on shellac, burn
readily at comparatively low temperatures. Oth-
ers melt or disintegrate without actually burn-
ing, or burn only if exposed to direct flame.

burning velocity See flame speed.

burnish To polish by friction; to make smooth
and lustrous.

burnishing Raising the gloss of a surface by
rubbing.

burn rate The rate at which a material will
bum after the ignition heat source has been
removed.

burnt brick Brick that has been treated in a
kiln at an elevated temperature to harden it,
give it mechanical strength, and improve its
resistance to moisture. Compare with unburnt
brick.

burnt lime See lime.

burnt sienna Sienna which has been calcined.

burnt umber See umber.

burr 1 . A waste brick from the kiln which has
been partially fused. 2. A batch of bricks fused
together. 3. A rough or sharp edge left on metal
by a cutting tool. 4. Same as burl, 1.

bursting strength 1. A measure of the ability
of a sheet to resist rupture when pressure is
applied to one side by a specified instrument
under specified conditions. 2. Of a pipe or fit-
ting, the internal pressure required to result in its
failure.

burst pressure Of a valve, the maximum pres-
sure which can be slowly applied to the valve
(e.g., at room temperature, for 30 seconds) with-
out causing it to rupture.

bus 1 . A busbar. 2. A heavy, rigid electrical con-
ductor that serves as a common connection
between the source of electric power and the
load circuits.

busbar A heavy, rigid electrical conductor (usu-
ally uninsulated copper or aluminum) which
serves as an interconnection between power-
handling devices (such as switches and circuit
breakers) or as a common connection between
several circuits.

bus duct, busway A prefabricated conduit
which is used to enclose and protect bus running
through it.

bush hammer A hammer having a serrated
face containing many pyramid-shaped points;
used to dress a concrete or stone surface; origi-
nally a hand tool but now usually power driven.
(See illustration p. 156.)

bush-hammered concrete Concrete having
an exposed aggregate finish; usually obtained with
a power-operated bushhammer which removes

155

bushhammer finish

bush hammer

(by percussive cutting) the sand-cement matrix
about the aggregate particles to a depth ranging
from Vib to Va, in. (1.59 to 6.35 mm).

bushhammer finish A stone or concrete sur-
face dressed with a bushhammer; used decora-
tively or to provide a roughened traction surface
for treads, floors, and pavements.

bushing l.In plumbing, a pipe fitting which is
threaded on both the inside and the outside so
that it can be used to connect two pipes (or other
fittings) of different sizes. 2. A sleeve which screws
into, or is otherwise fastened to, an opening in
order to prevent mechanical abrasion or damage
to a cable, rod, or the like, which passes through it.

business district That area of a town or city
used for commercial purposes, which is usually
defined and limited by zoning ordinances.

busway See bus duct.

butcher block, chopping block An assem-
bly of rectangular blocks of hardwood which are
edge-glued, joined by dowels, and then pressed
together hydraulically; esp. used as a work sur-
face in a kitchen.

butler's pantry A small service room, situated
between a kitchen and dining room, usually
equipped with a sink and cupboards, a small
stove, and often with a supplementary refrigera-
tor and appliances.

butler's sink Same as Belfast sink.

buttery (Brit.) Buttery; butler's pantry.

butment Same as abutment.

butment cheek The face of a material sur-
rounding a mortise, and abutted by the shoulders
surrounding the tenon.

butt l.A short length of roofing material. 2.
The thick end of a shingle. 3. A butt hinge.

butt and break The staggering of butt-lath
joints on framing members to add greater
strength to a wall and to reduce plaster crack-
ing.

butt-and-miter joint A carpentry joint hav-
ing a butt on the top half of the face and a miter
on the lower half.

butt block In a timber truss, a wood block
added to a compression joint.

butt casement hinge A type of butt hinge

commonly used on casement sashes.

butt chisel A wood chisel with a short blade,
esp. used for setting hardware on doors and door-
frames.

23E3^

butt chisel

butted frame A doorframe which has a thick-
ness less than or equal to the thickness of the
wall in which it is set; the frame butts against the
wall opening.

butt end The thicker end of a timber, handle,
etc.

butt-end treatment A technique of preserv-
ing timber posts by soaking the ends (which
may be exposed to soil and/or water) in wood-
preservative chemicals such as creosote or
pentachlorophenol dissolved in a fluid such as
diesel fuel oil.

butter l.To smooth on plastic roofing cement
or roofing adhesive with a trowel, as on a flash-
ing. 2. To apply mortar as to a masonry unit,
with a trowel.

buttercup yellow See zinc chromate.

butterflies Color imperfections in lime-putty
finish. If unscreened lime has lumps which are
not broken up in mixing, white spots occur in
the finish as the lumps break down in troweling
the plaster on the wall.

butterfly See butterfly wedge.

butterfly damper See butterfly valve.

156

butt joint

butterfly hinge A decorative hinge having
the appearance of a butterfly.

butterfly nut A wing nut.

butterfly roof A roof shape which has two sur-
faces that rise from the center to the eaves with
a valley in the center; resembles the wings of a
butterfly.

butterfly spring A light metal spring, set
over the pin of a door hinge.

butterfly tie Same as butterfly wall tie.

butterfly valve A valve used to control the
flow of fluids; a disk controls flow through the
port. Also called a butterfly damper.

Lever

Disc

butterfly valve

butterfly wall tie A wall tie manufactured
from heavy steel wire and shaped like a figure 8.

butterfly wedge, butterfly A double dove-
tail for joining two boards at their edges.

buttering Spreading mortar on a masonry unit
with a trowel.

buttering trowel A small trowel used
spread mortar on a brick before it is laid.

buttering trowel

butternut, white walnut A moderately soft,
medium-textured, low-density wood of light to
pale brown color. The walnut-like grain is used
particularly for decorative veneer.

buttery 1. Pantry or wine cellar; formerly a
medieval storeroom for provisions (originally
bouteillerie) . 2. (Brit.) Dispensary of provisions,
esp. food and drink, to college students.

butt fusion A method of joining plastic pipe,
sheet, or other similar forms of a thermoplastic
resin wherein the two ends to be joined are
heated to the molten state and then rapidly
pressed together to form a homogeneous bond.

butt gauge See marking gauge.

butt hinge A door or window hinge consist-
ing of two rectangular metal plates which are
joined with a pin; in large hinges of this type
the pin is removable, whereas in small hinges it
usually is fixed; fastened to butting surfaces,
such as the face of the jamb and the edge of a
door.

■ ©

butt hinge

butt-hung door A door hung on butt hinges,

as opposed to pivots.
butt joint 1. A plain, square joint between two
members, where the contact surfaces are cut at
right angles to the faces of the pieces; the two
pieces are fitted squarely against each other
rather than lapped; also see oblique butt joint. 2.

157

butt-joint glazing

butt joint formed by two boards

buttonwood Same as North American syca-
more.

buttress An exterior mass of masonry set at an
angle to or bonded into a wall which it
strengthens or supports; buttresses often absorb
lateral thrusts from roof vaults. Also see flying
buttress, hanging buttress.

welded butt joint

A joint in which the structural units being
joined abut each other so that under movement
any sealant is in tension or compression between
the joint faces.

butt-joint glazing A glass installation tech-
nique in which two glass panels do not meet in
a mullion; instead, a weatherproof vertical
joint is formed between them by means of a
sealant.

button 1. A small projecting member such as a
piece of wood or metal; used to fasten the frame
of a door or window. 2. A turn button.

button catch Same as button, 1.

buttonhead The head of a bar, bolt, rivet, or
screw which is hemispherical in shape; usually
the head is less than a full hemisphere and has a
flat bearing surface.

buttonhead

button punching Punch- like crimping at
regular intervals along the lap of adjacent
metal decking panels; used to lock the panels
together.

button set A rivet set used to give a rivet head
a button shape.

buttresses

buttress pier 1 . A pier acting as a buttress by
receiving lateral thrusts. 2. The part of a but-
tress which rises above the point of thrust of a
vault.

buttress pier

158

Byzantine architecture

buttress tower A tower which flanks an

arched entrance and acts, or appears to act, as a

buttress.
butt splice A butt joint, 1 which is secured

by nailing a piece of wood to each side of a

joint.

butt splice

butt Stile See hanging stile, 1.

butt strap A metal strap or plate which covers

and secures both pieces of a butt joint, 1.
butt veneer, stump veneer Curly figured

veneer cut from the root or stump of a tree.
butt weld A welded butt joint, 1 .
buttwood, stump wood Wood cut from the

base or stump of a tree.
butyl rubber Synthetic rubber that is made by

the polymerization of isoprene and isobutylene;

provides good resistance to aging, weathering,

and high levels of moisture.
butyl stearate A colorless oleaginous material,

practically odorless, used as damp-proofing for

concrete.
buzz saw Same as circular saw.
BV Abbr. for butterfly valve.
BW Abbr. for butt weld.
BX, BX cable A flexible, multi-conductor

armored cable having an outer protective

RUBBER
COVERED WIRES.

covering consisting of a helically wound steel
strip; used for connections to electric equip-
ment and in wiring houses.

by-altar A subordinate altar.

bypass Any device (such as a pipe or duct) for
directing flow around an element instead of
through it.

by-pass door See double sliding door.

bypass valve A valve (usually in a closed posi-
tion) which is used as the control device in a
bypass.

bypass vent A vent stack which runs parallel
to a soil stack (or a waste stack) and is connected
to it at frequent intervals.

byre A stable for livestock; a cow shed.

byzant See bezant.

Byzantine arch Same as horseshoe arch.

Byzantine architecture The architec-
ture of the Byzantine or Eastern Roman
Empire which developed from Early Christ-
ian and late Roman antecedents in the 4th
cent., flourished principally in Greece, but
spread widely and lasted throughout the
Middle Ages until the fall of Constantinople
to the Turks (1453). It is characterized by
large pendentive-supported domes, round
arches and elaborate columns, richness in
decorative elements, and color. The most
famous example is the Hagia Sophia in
Istanbul (532-537).

Byzantine architecture

159

Byzantine Revival

Byzantine Revival The reuse of Byzantine
forms in the second half of the 19th century; an
architectural mode found to a limited extent
that borrows special features of Byzantine archi-
tecture, including pendentive-supported domes,
round arches, elaborately decorated columns,

and capitals. a capital in Byzantine architecture

160

1/C Abbr. for "single conductor."

2/C Abbr. for "two conductors."

C l.On drawings, abbr. for course. 2. Abbr. for
centigrade or "Celsius."

C&Btr. In the lumber industry, abbr. for "grade
C and better."

Caaba Same as Kaaba.

CAB Abbr. for cement-asbestos board.

CAB. On drawings, abbr. for cabinet.

cabana l.An open or tent-like structure at a
swimming pool or at the shore. 2. Originally, a sim-
ple Spanish dwelling resembling a hut or cabin.

cabanne A primitive one-room dwelling used
by the early French pioneers in the Mississippi
Valley as a temporary shelter; had a framework
consisting of poles with branches woven
between them; a steeply pitched gable roof,
thatched with palmetto fronds or bark attached
to a wood framework; somewhat similar to the
palma hut in Florida.

cabin A simple one-story cottage or hut, often
of relatively crude construction; see center-hall
cabin, continental cabin, dog-run cabin, dogtrot
cabin, double-pen cabin, log cabin, possum-
trot cabin, saddlebag cabin, single-pen cabin,
stone cabin, tourist cabin, vertical log cabin, Vir-
ginia cabin.

cabin court A motel, usually consisting of
individual cabins.

cabinet 1 . A private room for study or confer-
ence. 2. A suite of rooms for exhibiting scientific
and artistic curiosities. 3. A case or box-like
assembly consisting of shelves, doors, and draw-
ers and primarily used for storage. 4. An enclo-
sure having a front hinged door or doors, for
housing of electrical devices or conductor con-
nections. 5. In French Vernacular architecture
of Louisiana, one of two areas at the rear corners
of a typical house; one was used for sleeping or
storage, and the other used to house a stairwell.

cabinet conditioner See room air conditioner.

cabinet drawer kicker See drawer kicker.

cabinet drawer runner See drawer runner.

cabinet drawer stop See drawer stop.

cabinet file A single-cut file, half-round on
one side, flat on the other.

cabinet filler A wood member which closes
the space between cabinets and adjacent walls or
ceilings.

cabinet finish A varnished or polished hard-
wood interior finish as distinguished from a
painted softwood finish.

cabinet heater A heater containing a heating
element enclosed in a metal cabinet, usually
with an intake grille below, and an outlet for the
heated air above; often contains a fan.

cabinet jamb A steel doorframe in three or
more pieces applied as the finished frame over a
rough buck.

cabinet lock A spring bolt.

cabinet scraper A flat steel blade used for
smoothing a wood surface after it has been planed,
or for scraping paint, etc., from the surface.

cabinet window A type of projecting window
or bay window for the display of goods in shops;
much used early in the 19th cent.

cabinet window

161

cabinet work

cabinet work Built-in cabinets and shelves,
often of fine quality, as in joinery.

cable l.An electric conductor consisting of a
group of smaller-diameter conductor strands
twisted together. 2. A group of electric conduc-
tors which are insulated from each other. 3. Any
heavy rope or wire line used for support, for
exerting a force, or for controlling a mechanism.
4. One of the reedings which are set into the
flutes of a pilaster or column.

cable bond An electrical connection (a)
between the armor or sheath of one cable and
that of an adjacent cable, (b) across a joint in
the armor or sheath of a cable, or (c) between the
armor or sheath and the earth.

cable conduit See conduit, 1. Also see cable
duct.

cabled fluting, ribbed fluting, stopped
flute A molding of convex section formed in
the flutes of a column, usually in the lower third
of the shaft.

cable duct A rigid metal duct through which
insulated electric conductors are run, generally
conductors carrying large currents; for under-
ground installations, concrete pipes usually are
used.

cable grip A device temporarily connected to

the end of a cable to assist in pulling the cable

during its installation.
cable jacket The protective covering over the

core, insulation, or sheath of a cable.
cable molding See cabling.
cable pulling compound A substance which

facilitates the pulling of wires through a cable

duct or conduit.
cable rack Same as ladder cable tray.

cable roof A structural system consisting of a
roof-deck and covering which are supported by
cables.

cable sheath A single layer or multiple layers
of a protective covering over a cable.

cable support box In an installation of elec-
tric conduit that runs vertically, a box which pro-
vides support for the cables within the conduit so
as to limit the strain on them from their own
weight.

cable-supported construction A structure
that is held in equilibrium by cables.

cable tray An assembly of metalwork which is
used to support insulated electric conductors;
similar in function to a metal cable duct, but
consisting of a ladder-like metal framework on
the bottom and sides, with the top open.

cable tray

cable vault An underground structure used in
pulling or splicing electric cables which are laid
underground.

cableway An apparatus for moving material,
sometimes used at construction sites; usually a
wire rope which is suspended between two
points, from which buckets, or the like, are hung
and pulled along.

cabling, cable molding 1. An ornament
formed like a cable, showing twisted strands. 2.
The convex filling of the lower part of the flutes of
classical columns. Also see rope molding, reeding.

.vwvv

cabling, 1

Cabot's quilt An insulating material consist-
ing of dried eelgrass held between layers of cloth
or paper; once used as thermal insulation, now
little used.

162

Cajun cottage

CAB plastic See cellulose acetate butyrate
plastic.

cab-tire cable A flexible cable having a heavy

rubber or neoprene outer sheathing.
CAD Abbr. for computer-aided design.

cadaster A public record or survey of the value,
extent, and ownership of land that serves as a
basis for taxation.

cadastral survey A survey relating to land
boundaries and subdivisions, made to create
units suitable for transfer or to define the limita-
tions of title.

cadmium plating An electroplating which
provides a corrosion-resistant coating on metal.

cadmium yellow A strong yellow pigment,
cadmium sulfide, characterized by good perma-
nence; used in paints.

caementicius In ancient Rome, irregular
masonry built of rough quarry stones not squared
or shaped in any way.

caementum Ancient Roman masonry formed
of small rough stones set in a mixture of concrete.

caged beam A beam enclosed in a casing, 2,

usually by a fire-rated construction.

Caen stone A stone from Caen (in Normandy)
used in some medieval buildings in England.

caer» A prefix signifying a fortified wall, castle,
or city, occurring in place names in Wales and
parts of western and northern England.

Caernarvon arch Same as shouldered arch.

cage 1. Any rigid, reinforced assembly, ready for
placing in position. 2. A metal enclosure for bal-
cony spotlights. 3. A chantry or chapel screened
by open tracery.

caged beam

caged column A column enclosed in a casing,
2, usually by a fire-rated material; also see col-
umn casing.

cage of reinforcement A system of concrete
reinforcement bars; see illustration under rein-
forcing rods.

caher In Ireland, ancient stonework thought to
have been intended for defensive work for a
church or for several sacred buildings.

cairn A pile of stones heaped up for a landmark,
memorial, or monument; a tumulus.

caisson l.A watertight structure or chamber,
within which work is carried on in building
foundations or structures below water level. 2. A
sunken panel, esp. in a vaulted ceiling or the
inside of a cupola; a coffer.

caisson drill An auger-like machine (or an
attachment for a crane) used in foundation work
to cut a vertical or inclined circular shaft in the
earth for a building footing which is carried to
solid material beneath.

caisson pile A cast-in-place pile; made by driv-
ing a tube into the ground, emptying the tube,
then filling with concrete.

Cajun cottage, Cajun cabin A simple dwel-
ling built by immigrants (Acadians) from the Mar-
itime Provinces of Canada who, from about 1760
to 1790, settled largely in the bayou districts of
southern Louisiana where their descendants are
now usually referred to as Cajuns. In the early
1800s, the typical Cajun cottage was built on

163

caking

Cajun cottage

groundsills, supported on cypress blocks or brick
piers; usually characterized by a shingle-covered,
moderately steep end-gabled roof; hand-riven
clapboard siding; rooms positioned in a relatively
straight line from the front to the back of the
house; French doors at the front and rear to pro-
mote the flow of air through the house; a porch
across the front, commonly without a railing; usu-
ally a steep stairway from one end of the porch to
a loft above; battened doors; battened shutters on
the windows.

caking In paints, the formation of a hard dense
mass of pigment which is difficult to disperse by
hand agitation.

CAL On drawings, abbr. for "calorie."

calathus The basket-shaped or bell-shaped core
of a capital, esp. Corinthian.

calcareous Containing calcium carbonate or,
less generally, containing the element calcium.

calcimine, kalsomine A low-cost wash coat-
ing consisting of glue and whiting (usually pow-
dered calcium carbonate) mixed with water,
sometimes tinted; used on plaster or masonry-
type surfaces.

calcine To heat a substance below the tempera-
ture of fusion to drive off chemically combined
water or to alter its chemical and physical
characteristics.

calcined gypsum A gypsum that has been
partially dehydrated by heating.

calcite A mineral form of calcium carbonate;
the principal constituent of limestone, chalk,
and marble; usually a major raw material used in
Portland cement manufacture.

calcite streak A former fracture or parting
(in limestone) that has been recemented and
annealed by deposition of calcite.

calcium aluminate cement, aluminous
cement, (Brit.) high-alumina cement

The product obtained by pulverizing clinker,
consisting essentially of hydraulic calcium alu-
minates resulting from fusing or sintering a suit-
ably proportioned mixture of aluminous and
calcareous materials.

calcium carbonate A low-density white pig-
ment for use in paint; provides little opacity;
used mainly to provide bulk and flatness.

calcium chloride A chemical salt used in
plastic concrete as an accelerator.

calcium hydroxide Same as hydrated lime, 2.

calcium oxide See lime.

calcium silicate brick Same as sand-lime
brick.

calcium silicate insulation Hydrated cal-
cium silicate with inorganic fiber reinforcement,
molded into rigid shapes.

calcium stearate A product of the reaction of
lime and stearic acid; used as an integral water
repellant in concrete.

calcium sulfate Anhydrite or gypsum dihy-
drate which has been calcined to the point at
which all the water of crystallization has been
removed.

calcium sulfate cement A cement that
depends primarily on the hydration of calcium
sulfate for its setting and hardening properties;
includes Keene's cement, Parian cement, plaster
of paris.

calcium sulfate hemihydrate Gypsum
which has been calcined to the point at which
75% of the water of crystallization has been
removed.

calculated live load 1. The live load which is
specified by the applicable building code. 2. The
actual load applied in service.

calculon A brick 21.9 cm long, 17.8 cm wide,
and 6.6 cm high.

caldarium The hot plunge in a Roman bath.

calefactory A heated common room in a
monastery.

calendar A sculptured or painted emblematic
series of the months.

calfdozer A small bulldozer.

calf's-tongue molding, calves'-tongue
molding A molding consisting of a series of

164

calorifier

W:i . ■ -'*'*•

calendar from portal of Amiens Cathedral, 13th cent.

calf's-tongue molding

pointed tongue-shaped elements all pointing in
the same direction or toward a common center
when around an arch.

calfiz In Hispanic architecture, a rectangular
ornamental frame around a door.

calfret An early term for caulk.

caliber The nominal internal diameter of a
pipe. In contrast, the outside diameter is speci-
fied for brass and copper tubing and for brass and
copper pipe of other than iron-pipe sizes.

calibre Same as caliber.

caliche Gravel, sand, or desert debris cemented
by porous calcium carbonate or other salts.

caliduct 1. A duct or pipe for conveying hot air,
hot water, or steam for heating. 2. In the ancient
Roman systems of furnace heating, a hot-air flue,
usually of terra-cotta or built up with brick parti-
tions and tile facings.

California bearing ratio A ratio used in
determining the bearing capacity of a founda-
tion; defined as the ratio of the force per unit
area required to penetrate a soil mass with a 3 sq
in. (19.4 sq cm) circular piston at the rate of
0.05 in. (1.27 mm) per min to the force required
for corresponding penetration of a standard
crushed-rock base material; usually determined
at a penetration of 0.1 in. (2.54 mm).

California bungalow, California Crafts-
man A loosely used term applied to a small

one-story or one-and-a-half-story wood bun-
galow, often in the Craftsman style; widely
found in California from about 1890 to 1920
as well as in other areas of the United States.

California ranch house See ranch house.

caliper An instrument, resembling a pair of
dividers, with adjustable legs for measuring the
diameter or the thickness of bodies. Also see
inside caliper and outside caliper.

ADJUSTABLE

FIRM JOINT

caliper

caliper stage In a theater, a stage having side
arms, which may be used for acting, on both
sides of the main stage or apron.

calking Same as caulking.

calliper Same as caliper.

call box See fire alarm box.

call loan A loan that is payable at any time on
the demand of the lender; in some instances, the
borrower may also have the right to repay the
loan at any time he chooses.

call for bids A formal request for bids for work
to be performed on a building project.

call point See fire-alarm box.

calme See came.

calorie The heat required to raise the tempera-
ture of 1 gram of water 1°C; now called a small
calorie. A large calorie is equal to 1000 small
calories, i.e. a kilocalorie.

calorific value The amount of heat liberated
by the combustion of a unit weight (or if a gas, a
unit volume) of fuel.

calorifier (Brit.) A storage vessel, not open to
the atmosphere, in which a supply of water is
heated.

165

calotte

calotte A dome, cupola, or structure of similar
form, as a cup-shaped ceiling, the head of an
alcove, etc.

calves '-tongue molding See calfs-tongue
molding.

calyon Flint or pebble-stone; used in building
walls, etc.

calyx An ornament resembling the outer pro-
tective covering of a flower; found, for example,
in the Corinthian capital.

cam In a lock, a rotating piece attached to the
end of the cylinder plug to engage the locking
mechanism.

CAM On drawings, abbr. for camber.

camara Same as camera.

camarn In a church, a camera, 3 used for stor-
ing images, adornments, and the like.

camber 1 . A slight convex curvature built into
a truss or beam to compensate for any antici-
pated deflection so that it will have no sag when
under load. Also see bow. 2. A slight convex
curvature of any surface, e.g., to facilitate the
runoff of water.

camber arch An arch having little rise; essen-
tially a flat arch having a slightly upward curve
toward its midpoint.

camber beam A beam curved slightly upward
toward the center.

camber board A template which performs the
same function as a camber diagram.

camber diagram A diagram, used in construc-
tion, which indicates the specified camber at all
points along the length of a truss or beam.

camber piece, camber slip A slightly curved
wood board used as a support in laying a brick
arch having a small rise.

camber window A window arched at the top.

cambium The cellular layer of wood tissue
between the bark and sapwood of a tree.

camboge A concrete masonry unit with trans-
verse openings; used in tropical architecture,
often decoratively, to permit ventilation while
excluding sunlight, as in a brise-soleil.

came A slender rod of cast lead, with or without
grooves, used in casements and stained-glass win-
dows, to hold together the panes or pieces of glass.

cambium

camelback truss A truss having a broken out-
line for the upper chord, composed of a series of
straight segments, taking the humped shape of a
camel's back.

camelhair mop A soft-haired brush which is
used for varnishing, gilding, and filling in narrow
spaces.

camera l.In ancient architecture, an arched
roof, ceiling, or covering; a vault. 2. A room
having an arched ceiling; a vaulted room. 3. A
small room, small hall, or chamber.

camerated Having an arched or vaulted
appearance.

camera vitrea A vaulted ceiling, having its
surface lined with plates of glass.

cam handle, locking handle In a window
having a sash (ventilator, 2) which swings
about pivots, a handle which locks the sash in
a closed position by wedging it against a
keeper.

campana The body of a Corinthian capital.

campanario In Mission architecture, a belfry
or a pierced wall that serves as a belfry, with a
bell usually hung in an arched opening.

campaniform Bell-shaped.

campanile A bell tower, usually freestanding.

166

cane bolt

campanile

campanulated Bell-shaped.

camp ceiling 1. A ceiling shaped like the inte-
rior of a truncated pyramid. 2. The ceiling
within the roof of a building, the sides of which
are sloped, following the line of the rafters, but
the center of which is flat. 4. A ceiling that sags
inwardly like a tent. Also called a camp ceiling
or tent ceiling.

camp sheeting Sheetpiling used for founda-
tion work in sandy soil.

campus The grounds and buildings of a univer-
sity, college, or school.

can Abbr. for canvas.

Canadian Standards Association In
Canada, a membership organization serving
industry, educational institutions, and govern-
ment in the field of standardization, including
the standardization of building components,
materials, and testing. Also see Construction
Specifications Institute Canada.

canal, canalis A channel or groove, as a hol-
low between the fillets of the volutes of an Ionic
capital.

canale In Spanish Colonial architecture, a
waterspout used to drain rainwater from an
essentially flat roof; it projects through, and
beyond, the face of the parapet around the roof.

canaliculus A small channel or groove, as a
fluting carved on the face of a triglyph.

canary whitewood Same as tulipwood, 1.
canary wood See balaustre.

cancela In Spanish architecture and its deriva-
tives, a large gate often of ironwork or a massive
wood gate, usually decorated with spindlework
or a lattice grille.

cancelli Barred screens in a basilica, separating
the clergy from the laity, in Early Christian
architecture.

candela The International Standard unit of
luminous intensity; closely approximates the for-
merly accepted unit known as the "international
candle."

candelabrum 1 . A movable candle lampstand
with central shaft and, often, branches or a dec-
orative representation thereof. 2. A lighting
device designed as an architectural fixture,
composed as in definition 1, above. Also see
lamppost.

candela per unit area See luminance.

candle beam In old churches, a horizontal
beam, bar, or rail furnished with prickets for
holding candles, each of which has a saucer or
tray to catch the drippings; placed over or near
the altar, and also at the entrance to the choir or
chancel, where the rood beam or rood screen
was placed in richer churches.

candlepower (cp) The luminous intensity of
a light source, expressed in candelas. Abbr. cp.
Also see apparent candlepower.

candle-snuffer roof Same as conical roof.

cane bolt A heavy cane-shaped bolt with the
top bent at right angles; installed at the bottom
of a door.

s^=>

EJfrzi

:bolt

167

cane fiberboard

cane fiberboard A fiberboard primarily com'
posed of sugar-cane fibers after juice has been
extracted from the cane (bagasse); held together
by a binder.

canephora, canephorus 1. Ornament repre-
senting a maiden (youth) bearing a basket of
ceremonial offerings on the head. 2. A caryatid
with basket on her head; used either as a support
or as a freestanding garden ornament.

canephora

cannelated Said of a surface that is fluted or

grooved.
cario A water conduit, pipe, or clay-tile spout on
a Hispanic building.

canonniere A hole left in a retaining wall
to permit water in the earth behind the wall to
drain through it.

canopy l.A decorative hood above a niche,
pulpit, choir stall, or the like. 2. A covered area
which extends from the wall of a building, pro-
tecting an entrance or loading dock. 3. The
collective term for the upper blanket of foliage
on trees.

canopy of honor Same as celure.

canopy roof A roof, often over a balcony
or porch, that is suggestive of the curvature of a
suspended cloth canopy.

canopy, 1

cant l.A salient corner. 2. A line or surface
angled in relation to another, as a sloped wall. 3.
Masonry "on cant" is laid with joints sloping
between front and back surfaces; the vertical
joints are laid normally. 4. A log partly or wholly
squared off.

cant bay A bay erected on a plan of canted
outline.

cant-bay window A cant window.

cant beam A beam having its edges beveled or
chamfered.

cant board A board which is laid so as to cant
a surface, as under the first row of shingles on a
roof, or to support lead sheeting on each side of
a valley gutter; a cant strip.

cant brick See splay brick.

canted Having a cant, 2; said of a wall, etc.
canted coursing Moderately-pitched courses
of brick or masonry in a vault.

canted molding A wood raking molding.

canted wall A cant wall.

cantharus A fountain or basin in the atrium or
courtyard before ancient and some Oriental

168

cant strip

churches, where persons could wash before
entering the church.

cantherius A principal rafter in an ancient
wooden roof.

cantilever l.A beam, girder, truss, or struc-
tural member or surface that projects horizon-
tally beyond its vertical support, such as a wall
or column. 2. A projecting bracket used for
carrying the cornice or extended eaves of a
building.

«-5$;

cantilever, 2

cantilever arch An arch that is supported by

flat projections on opposing walls.
cantilever barn A barn having its second floor

projecting beyond the structure of the ground

floor; especially found in the southern regions of

the US.
cantilever beam A beam which is supported

only at one end.
cantilevered window Same as oriel.
cantilever footing A footing having a tie

beam to another footing to balance a structural

load not symmetrically located with respect to

the footing.
cantilever form Same as slip form.
cantilever retaining wall See cantilever

wall.

cantilever steps Steps built into the wall at
one end, but supported at the other end only by
the steps below.

cantilever truss A truss overhanging its sup-
port at one end and anchored at the other.

cantilever 'wall A reinforced concrete wall
which resists overturning by the use of cantilever
footings.

canting strip A water table, 1.

cant molding A square or rectangular molding
with the outside face beveled.

cantilever wall

canton A corner of a building decorated with a
projecting masonry course, a pilaster, or similar
feature.

cantoned Ornamented at the corners with pro-
jecting pilasters.

cantoned pier Same as pilier cantone.

cantoria A church choir gallery.

cantoris Of (or belonging to) the cantor or pre-

cantor, for example — the cantoris side of the

choir in a church; the left or north side as one

faces the altar.
cant strip 1 . A beveled strip of wood or other

material used esp. under built-up roofing where

169

cant wall

-•—SIDING

FLASHING
-^- BUILT-UP ROOF

cant strip, 1

the roofing turns up, providing a gradual transi-
tion; used to prevent the cracking of roofing
applied over it; as arris fillet. 2. A tilting fillet; a
doubling piece. 3. A cant board.

cant wall A wall canted on plan.

cant window, cant-bay window A bay
window erected on a plan of canted outline; the
sides of the window are at an angle with respect
to the wall; also see angled bay window.

cant window

CANV On drawings, abbr. for canvas.

canvas A closely woven cloth of cotton, hemp,
or flax; sometimes adhered to a wall or deck to
serve as a substrate for paint; used to cover roof
decks that are walking surfaces or sun decks.

canvas wall A plastered wall to which a layer
of canvas has been applied to serve as a base for
wallpaper.

cap 1. Usually, the topmost member of any ver-
tical architectural element, often projecting,
with a drip as protection from the weather, e.g.,
the coping of a wall, top of a pedestal or but-
tress, the lintel of a door, etc. 2. A layer of con-
crete placed over rock in the bottom of
foundation excavations to level the exposed

surface, prevent its deterioration by weathering,
and protect it from other damage. 3. The upper
member of a column, pilaster, door cornice,
molding, and the like; also called cap trim,
wainscot cap, dado cap, chair rail cap, capital. 4.
A fitting used to close the top end of a tubular
newel. 5. A blasting cap. 6. A fitting used to
close the end of a pipe. 7. A plane surface which
is bonded to the bearing surface of a test speci-
men during its strength testing to ensure a uni-
form load distribution.
capacitance The quantitative measure of the
electric-energy storage capability of a capacitor;
usually measured in farads or microfarads (1CT 6
farads).

capacitance alarm A device which is elec-
trically connected to a protected metal enclo-
sure (such as a safe, vault, file, or security
cabinet) so that the enclosure itself becomes
part of a balanced-capacitance circuit. A per-
son approaching the protected cabinet unbal-
ances the electrical circuit and activates a
security alarm.

capacitor An electric component which con-
sists of conducting plates insulated from each
other by a layer of dielectric material; introduces
capacitance into a circuit.

capacitor motor A single-phase induction
motor with its main winding connected to a
source of power and having an auxiliary winding
connected in series with a capacitor to facilitate
starting.

capacity l.See carrying capacity. 2. The vol-
ume contained in a vessel. 3. The maximum or
minimum water flow obtainable under given
conditions (e.g., specified conditions of pressure,
temperature, and velocity).

capacity insulation The ability of masonry to
store heat; depends on its mass, density, and spe-
cific heat.

cap block Same as drive cap.

cap cable In prestressed concrete, a short cable
introduced to prestress the zone of negative
bending.

Cape Ann house A rectangular house, com-
monly one or one and a half stories high, that
is similar to a Cape Cod house, but has a shin-
gled mansard roof rather than a shingled gable
roof.

170

capital

Cape Ann house

cape chisel A long cold chisel which has a long
taper and a narrow cutting edge; used for cutting
key ways and the like.

Cape Cod house A colonial one-and-a-half-
story rectangular house of wood-frame construc-
tion that originated on Cape Cod, Massachusetts.
Usually characterized by: a massive central
chimney serving all fireplaces; a gable roof; a
roof covering and exterior wall covering of
hand-split wood shingles, left unpainted to
weather to a gray color; double-hung windows
on the first story and often on the gable-end
walls; paneled doors; a partial basement. Cape
Cod houses are of three types: full Cape house,
which has two windows on each side of the front
door; three-quarter Cape house, which has two
windows on one side of the front door and a sin-
gle window on the other side; and a half Cape
house, which has two windows on one side of
the front door and none on the other.

Cape Cod house

Cape house A term used in some parts of New
England for a Cape Cod house.

cap flashing Same as counterflashing.

capellaccio A local tufa stone used for building
construction in ancient Rome.

cap house A small enclosure, at the top of
stairs in a turret or tower, which leads to the
parapet around a roof.

capilla abierta A Hispanic open chapel, usu-
ally adjacent to a church.

capilla major 1. The principal chapel in
Spanish churches. 2. The area directly around
the high altar of a church.

capillary action, capillarity l.The move-
ment of a liquid in the interstices of soil or other
porous material, as a result of surface tension. 2.
The phenomenon responsible for dry soil suck-
ing up moisture above the ground water level.
Also see capillary flow.

capillary break A space between two surfaces
which is purposely made wide enough to prevent
the movement of moisture through the space by
capillary action.

capillary flow The flow of moisture through a
capillary pore system, as in concrete.

capillary groove A groove formed between
two building components to prevent capillary
action between them.

capillary joint Same as sweat joint.
capillary migration See capillary flow.

capillary space In cement paste, any space not
occupied by anhydrous cement or cement gel.
Air bubbles, whether entrained or entrapped,
are not considered to be part of the cement
paste.

capillary tube A tube of small internal diame-
ter; used in refrigeration as a control for the flow
of liquid refrigerant, or as an expansion device
between the condenser and evaporator; or used
to transmit pressure from the sensitive bulb of a
temperature control to the operating element.

capillary water Water, above the water table,
held there by capillary action.

capital The topmost structural member of a
column, pilaster, anta, or the like, often deco-
rated; may support an architrave, 1 or may be
surmounted by an impost. See illustrations
under the various orders; also see angle capital,
basket capital, bracket capital, bud capital,
Byzantine capital (illustrated under Byzantine

171

capital cost

n A3tragaJ

capital: nomenclature

capitals

architecture), Composite capital, Corinthian
capital, corner capital, cushion capital, Doric
capital, Hathoric capital, protomaic capital,
Ionic capital, lotus capital, palm capital, scal-
loped capital, water-leaf capital.

capital cost The cost of acquiring a building,
including any substantial improvements the
building may require.

capital messuage The main dwelling of a
manor house. See messuage.

capital Official meeting place for a legislative body.

cap molding, cap trim 1. Molding or trim
which embellishes the top of a dado. 2. Molding,
at the head of a window or door, above the sim-
ple trim of the casing.

cappella del coro The choir, or chapel of the
choir.

capping Any architectural member serving as a
cap, 1, such as a coping.

capping brick Same as coping brick.

capping in The application of roofing felt to a

roof-deck.
capping piece, cap piece, cap plate A

piece of timber covering the heads of a series of

uprights or other vertical structure.
capping plane A plane used for rounding the

upper surface of wooden railings.
cap plate l.A capping piece. 2. The top plate

on a steel column or post; usually supports a load.
cap rail A rail, 1 fastened to the uppermost

member of a railing system.
capreolus In an ancient timber roof, a brace or

strut; a king post or tie beam.
cap screw l.A screw which is threaded along

its entire length and has a chamfered point; it is

driven into a hole and secured without a nut. 2.

Same as tap bolt.

BUTTON MEAD HEXAGON HEAD

iwumiwlj^ wraomrn

FLAT HEAD FILLISTER HEAD

cap screws

cap sheet A coated felt, usually mineral-
surfaced; used as the top ply of a built-up roofing
membrane. See asphalt prepared roofing.

cap tile A tile used as a coping stone atop a wall.

capstone 1. Any single stone in a coping. 2. A
stone placed at the top of a stone arch.

captain's house In colonial New England, a
house having a truncated hipped roof and chim-
neys at both gable ends; has a widow's walk
and/or a cupola on the roof.

captain's walk See widow's walk.

cap trim See cap molding.

car See elevator car.

caracole A spiral stair.

car annunciator An electric device in an ele-
vator car which provides a visual indication of
floor landings.

carapa, crabwood, Surinam mahogany,
West Indian mahogany A pale to reddish
brown wood of South America and Africa; mod-
erately hard and heavy, with straight grain and
medium texture; used for general construction
and in plywood.

172

carnauba wax

caravansary, caravanserai 1. In the middle
east, a building or inn for the overnight lodging
of travelers by caravan; usually enclosed by a
solid wall and entered through a large gate. 2.
By extension, any large inn or hotel.

interior of a caravansary

carbonaceous Said of rock containing organic
matter.

carbon-arc cutting An arc-cutting process in
which the severing of metal is effected by melt-
ing with the heat of an arc produced between
the carbon electrode and the metal being cut.

carbon-arc lamp A high-intensity electric-
discharge lamp employing an arc discharge
between carbon electrodes.

carbon-arc spotlight A spotlight employing a
high-intensity arc light source.

carbon-arc welding An arc-welding process
wherein coalescence is produced by heating with
an arc between a carbon electrode and the work.

FILLER HOD

lding

carbon-arc we

carbonation The reaction between carbon diox-
ide and calcium compounds, esp. in cement paste,
mortar, or concrete, to produce calcium carbonate.

carbon black A synthetically produced black
pigment, almost pure carbon; used to color
paint and concrete because of its high shading
strength. Also see animal black.

carbon dioxide extinguishing system A
fire-extinguishing system in which the extin-
guishing agent is carbon dioxide supplied from a
pressurized vessel through fixed pipes and nozzles;

includes an automatic fire detection system and

an actuating mechanism.

carbon steel 1. Steel having no specified min-
imum content of alloying elements. 2. Steel
having a specified minimum copper content not
exceeding 0.40%. 3. Steel having a maximum
specified content as follows: manganese 1.65%,
silicon 0.60%, copper 0.60%.

carcase Same as carcass.

carcass, carcase 1 . The framework of a building
before the addition of sheathing or other covering.
2. The frame or main parts of a structure unfin-
ished and unornamented, lacking masonry, brick-
work, floors, carpentry, plastering, inside trim, etc.

carcass flooring The frame of timbers which
supports the floorboards above and the ceiling
below.

carcass roofing A framework of timber which
spans a building and carries the boarding and
other covering.

career l.A prison. 2. A starting stall in a
Roman circus for horse or chariot races. 3. The
dens for beasts in an amphitheater.

card frame, card plate A metal frame,
attached to a door or drawer, which holds a
name card or label.

cardo A hinge or pivot, used in ancient con-
struction to hang a door.
car door See elevator car door.

car door contact, gate contact An electric
device which prevents movement of an eleva-
tor car unless its door (or gate) is in the closed
position.

care, custody, and control Describes a stan-
dard exclusion in liability insurance policies.
Under this exclusion, the liability insurance
does not apply to damage to property in the care
or custody of the insured, or to damage to prop-
erty over which the insured is for any purpose
exercising physical control.

car-frame sling Same as elevator car-frame sling.

carillon l.A bell tower; a campanile. 2. A set
of fixed bells, usually hung in a tower and struck
by hammers.

Carnarvon arch A lintel supported on corbels.

carnauba wax A hard, high-melting-point
wax; used in wood polishes and coatings to pro-
duce a matte finish.

173

camel

carnel, crenelle Same as the embrasure of a
battlement.

carnificina In ancient Rome, a subterranean
dungeon in which criminals were tortured and
in many cases executed.

carol An area in a cloister set off by screens, par-
titions, or railings; similar in use to a carrel.

Carolean Said of the periods of the reigns of
King Charles I (1625-1649) and Charles II
(1660-1685) of England; also called Caroline.

Carolingian architecture The pre-Romanesque
architecture of the late 8th and 9th cent, in France
and Germany, based on Roman forms. So called
after the emperor Charlemagne (768-814). The
cathedral of Aachen is the best-known example.

carolytic, carolitic Descriptive of a column
having a foliated shaft.

carousel packer An automatic refuse com-
pactor in which compacted waste materials are
compacted and packaged in bags arrayed along a
circular carriage; designed for high-volume and/
or for long, unattended operation.

Cdrtiusel

carousel packer

car park (Brit. ) A parking lot.

Carpenter Gothic, Carpenter Gothic
Revival A mid- 19th century architectural style
in which highly decorative woodwork and Gothic
motifs were applied to otherwise simple homes or
churches in America, usually designed and con-
structed by carpenters and builders; often asym-
metric in plan. Buildings in this style are often
characterized by: a facade that promotes vertical

Carpenter Gothic

emphasis, such as by pointed arches that extend
into the gables; Gothic motifs such as foliated
ornaments, pinnacles with battlements, crockets,
decorative brackets, foils, towers, turrets, and wall
dormers suggestive of Gothic architecture; often,
an entry porch having a flattened Gothic or Tudor
arch; a steeply pitched roof or gabled roof, often
with a gable at the center of the facade or with
intersecting gables; lacy, highly ornate bargeboards
and finials decorating the gables and dormers; dec-
orative shingle patterns on the roof; high, orna-
mental chimney stacks; often, clusters of chimney
pots; bay windows, casement windows with dia-
mond-shaped or rectangular-shaped panes, lancet
windows, ogee-arch windows, oriel windows,
stained-glass windows, triangular arch windows
often with mullions and relatively thin tracery;
label moldings; often elaborately paneled entry
doors in a Gothic motif; a wood-paneled door or a
battened door suggestive of the medieval period,
sometimes bordered with sidelights. Occasionally
called Carpenter's Gothic.

carpenter's brace Same as brace, 3.

carpenter's bracket scaffold A scaffold con-
sisting of wood or metal brackets supporting a
platform.

carpenter's finish, Brit, joiner's finish Fin-
ish work by a carpenter, including the laying of
the finish flooring, the construction of stairs, the
fitting and installation of doors and windows,
exposed cabinet work and moldings, etc., but
excluding rough finish work such as framing.

carpenters' guides, carpenters' handbooks
See pattern book.

174

carpet tile

carpenter's level An instrument used by a
carpenter to determine a horizontal or a vertical
line; consists of a spirit level set in a straight bar
of wood or metal.

HORIZONTAL BUBBLE TUBE

VERTICAL BUBBLE TUBE

carpenter's level

carpenter's punch A nail set.
carpenter's square, framing square A flat,
steel square commonly used in carpentry.

i v i] gTWWW I' 1 ' 1 5 1 q ' J i yH ' ji 'i •

I .1 i I il . I il ■ I .1 i I

carpenter's square

carpentry A building trade which includes cut-
ting, framing, and joining the timbers or wood-
work of a building or structure.

carpet A heavy, durable floor covering, usually of
woven, knitted, or needle-tufted fabric; commonly
installed with tacks or staples, or by adhesives.

carpet construction

carpet backing The material on the underside
of carpet; usually made of cotton, carpet rayon,
kraft cord, or jute; may have a coating of latex.

carpet bedding Beds in which small annual
plants with ornamental foliage or flowers, and
perhaps gravel-filled sections as well, are
arranged in patterns to be seen from above.

carpet construction Descriptive of the method
by which a carpet is made, and how the pile fibers
are fixed to the carpet backing; the construction is
often classified as woven, tufted, or knitted.

carpet cushion Same as carpet underlayment.

carpet density The number of rows of pile
tufts per inch, lengthwise.

carpet face weight The weight of carpet pile;

in the US usually expressed in ounces per square
yard of pile.

carpet fiber The material of which the yarn of
the carpet pile is made, as wool, acetate, acrylic,
cotton, nylon, polyester, polypropylene, rayon, etc.

carpet float A wood float, covered with a piece
of dense-pile carpet; used in plastering to pro-
duce a fine-grained texture in a sand finish.

carpet installation See stretch-in carpet
installation.

carpet pile The tufts of yarn that stand erect
from the base of the carpet and whose ends form
the surface; the ends may be cut or looped.

carpet pile height The height of the pile yarn
above the backing material; usually expressed in
inches or millimeters.

carpet pitch The number of warp yarn ends per
inch crosswise of the loom; usually expressed in
terms of the number of pile yarn ends in a 27-in.
(68.6-cm) width of carpet.

carpet repeat In a roll of carpet which has a pat-
tern, the distance from a specific point in a pattern
figure to the same place where the figure occurs
again, as measured lengthwise along the carpeting.

carpet strip l.A molding used to fasten the
edge of carpeting. 2. A strip of wood (approxi-
mately equal to the carpet thickness) installed
on the floor at the threshold of a door.

carpet stuffers Extra yarn, usually jute, which
is run lengthwise through the center of the
fabric of carpet backing to add thickness and
weight.

carpet tile A square piece of carpet used to
cover a floor surface; commonly, such individual
pieces are cemented to the floor with an adhe-
sive to form a continuous surface.

175

carpet underlayment

carpet underlayment A padding material,
laid directly on the floor, over which carpet is
installed; usually manufactured of hair felt, foam
rubber, hair felt and jute, sponge rubber, or some
other combination of these materials.

carpet warp Yarn which runs lengthwise of
the fabric, passing alternately over and under
the weft yarns.

carpet weft Yarn which runs across the width
of the carpet, from selvage to selvage.

car platform Same as elevator car platform.

carport A covered automobile shelter associ-
ated with a separate dwelling. It has one or more
sides open to the weather.

carreau A single glass or encaustic tile, usually
square or diamond-shaped, used in ornamental
glazing.

carrefour 1 . An open place from which a number
of streets or avenues radiate. 2. By extension, any
crossroad or junction. 3. A public square or plaza.

carrel, cubicle A small individual compartment
or alcove in a library, used for semiprivate study.

carrelage Tiling; esp. the decorative tiling in
terra-cotta used in the Middle Ages for floors,
etc.; imitated in modern times.

carriage 1. An inclined beam which supports the
steps or adds support between the strings of a
wooden staircase, usually between the wall and
outer string. Also called a carriage piece, horse,
roughstring. 2. In theater stage equipment, a

CARRIAGE

counterweight arbor. 3. A movable frame on which
some other movable part or object is supported.
carriage bolt A threaded bolt having a circular
head, an oval or flat bearing surface, and a
means (such as a square shoulder under the
head) of preventing rotation of the bolt.

SQUARE OH COMMON

FINNED NECK

®H«=1

carriage, 1

RIBBED NECK
carriage bolts

carriage clamp A type of C-clamp used in

carpentry.
carriage house See coach house.
carriage piece See carriage, 1.

carriage porch A roofed structure over a
driveway at the door to a building, protecting
from the weather those entering or leaving a
vehicle. Also see porte cochere.

carriage shed A rough, roofed structure hav-
ing one or more open sides; once used as a tem-
porary shelter for horse-drawn carriages, as in
the yard of a church.

carriageway (Brit.) A road designed to carry
vehicular as opposed to pedestrian traffic; specif-
ically, the actual traffic lanes of such a road as
distinct from median strips or shoulders.

carrier 1. A mobile prime mover for transport-
ing construction machines; also may serve as
the working base or undercarriage of the
machine. 2. A container attached to or hung
from a trolley for moving a load from one point
to another on a construction site. 3. A carrier
angle or carrier bar which supports treads formed
from metal grating.

carrier angle An angle iron connected to the
inside face of a stair stringer to form a supporting
ledge for the end of a tread or riser.

carrier bar A flat metal bar which is used in the
same way as a carrier angle.

176

carved work

carrol Same as carrel.

carrying capacity Of an electric cable or wire,
same as ampacity.

carrying channel In suspended ceiling con-
struction, a three-sided metal member used to
support the entire ceiling assembly.

carrying freezer A cold-storage room, where
the temperature usually is maintained between
-20°F (-28.9°C) and 20°F (-6.7°C).

carry up In masonry and brickwork, to build up
a wall to a specified height.

car safety A mechanical device attached to an
elevator car frame, or to the counterweight
frame, designed to stop and hold the car or coun-
terweight in case of a predetermined overspeed
of the car or its free fall, or in the event that its
hoisting ropes slacken.

car-switch operation Operation of an eleva-
tor car in which the movement and direction of
travel of the car are directly and solely under the
control of the operator by means of a manually
operated car switch or continuous-pressure but-
tons in the car.

cart house An enclosure, such as a shed, for
sheltering two-wheeled horse-drawn vehicles
that are intended for two passengers.

cartload The quantity a cart will carry, usually
Va to 1 cu yd (approx. 0.2 to 0.8 cu m).

carton pierre A mixture of glue, whiting, paper-
pulp, and chalk; molded, dried, and finished to
form durable, usually interior, architectural
embellishments imitating stone, metal, etc.; a
kind of papier-mache used for making lightweight
cast ornaments where plaster would be too heavy.

cartoon A drawing or painting made as a
detailed model, often full-scale, of an architec-
tural embellishment.

cartouche l.An ornamental tablet often
inscribed or decorated, and framed with elabo-
rate scroll-like carving. 2. A modillion of
curved form. 3. In Egyptian hieroglyphics and
derivatives, a frame around the Pharaoh's name.

cartridge Same as cartouche.

cartridge fuse A fuse enclosed in a cylindrical
tube, which protects an electric circuit against
the excessive flow of current.

cartridge heater An electric heating coil,
enclosed in a metal case shaped like a cartridge.

cartouche, 1

<=GZZD=

cartridge fuse: a section of the enclosed fuse is shown in the
lower figure

cartridge-type filter A water filter in the form
of a cartridge.

FILTER HEAD

FILTER

ELEMENT

(CARTRIDGE)

cartridge-type filter

carved 'work l.In stonework, hand-cut orna-
mental features which cannot be applied from
pattern. 2. In brickwork, carving, usually on
bricks of larger than ordinary size.

carved work, 1 : an Early English carved capital

177

carvel joint

carvel joint A flush joint between adjacent
planks.

caryatid A supporting member serving the
function of a pier, column, or pilaster and carved
or molded in the form of a draped, human,
female figure. See canephora.

casa del campo In Spanish Colonial architec-
ture and its derivatives, a one-story country
house usually built around a patio, constructed
primarily of adobe and wood; had a mission tile
roof having a central ridge, or a shed roof having
a single shallow pitch, usually with considerable
overhang to provide shade.

casa del pueblo, casa del poblador In
Spanish Colonial architecture of the 18th and
19th centuries, a house in a village or town usu-
ally constructed of adobe brick that has been
plastered and whitewashed; had a mission tile
roof supported by beams that penetrated the
walls, and wood-framed casement windows, with
the windows facing the street protected by grilles
or gratings.

casa del rancho In Spanish Colonial architec-
ture and its derivatives, especially in the 18th
and 19th centuries, the main dwelling of a ranch
that usually included: a large courtyard entered
by way of a massive wooden gate; a corral; a par-
tially enclosed or fully enclosed patio; living
quarters for all members and servants of the
household, housing for domestic animals, and
associated storage spaces.

casa de tablas Same as tabla house.

cascade refrigerating system A refrigera-
tion system consisting of two or more refrigerant
circuits, each with a pressure-imposing element,
condenser, and evaporator; the evaporator of
one circuit cools the condenser of the other cir-
cuit, which is at a lower temperature.

case l.To cover one building material with
another. 2. Same as casing, 1. 3. The housing
containing a lock mechanism. 4. A unit in
which food is displayed and protected; often
partially constructed of clear glass or plastic
and thermally insulated; usually counter-top or
wall-mounted.

case bay That section of a floor or roof between
two principals or girders.

cased beam l.A beam having a casing, 2.
2. Same as caged beam.

ed be

cased pile A concrete pile made by casting
concrete within a steel casing placed into the
ground; a cast-in-place pile.

cased-in timber Same as cased beam.

cased column Same as caged column.

cased frame, boxed frame, box frame
The wood frame of a double-hung window; has
hollow jambs or mullions which contain the
sash counterweights.

cased glass, case glass, overlay glass Glass
formed of two or more fused layers of different
colors; the top layer may be cut, permitting a
lower layer to show through.

cased opening, trimmed opening An open-
ing between rooms which is finished with door-
jambs and trim but does not have a door hung
in it.

cased post A post having a casing, 2.

cased post

cased sash-frame A cased frame.

case-hardened l.Said of a piece of material
fabricated of steel or iron alloy whose surface

178

casing

has been hardened by a special process: first by
carburization and then by heat treatment. 2.
Said of timber whose outer layers have dried too
rapidly during seasoning.

case-hardened glass Same as tempered glass.

case-hardening l.In timber, a condition in
which the outer layers have dried without
shrinkage, causing stress between the inner and
outer layers. 2. Producing a hard surface layer on
steel, as by carburizing, cyaniding, carbonitrid-
ing, nitriding, induction hardening, and flame
hardening.

casein A protein; the chief nitrogenous ingredi-
ent of milk.

casein glue Glue made from milk protein; esp.
used in carpentry and joinery.

casein paint A paint made from a mixture
of skimmed milk or buttermilk, earth-colored
pigment, water, and a small amount of lime;
widely used in the US and in Britain during the
18th and 19th centuries.

case lock A surface-mounted lock, such as a
box lock.

casemate A vault or chamber in a bastion, hav-
ing openings for the firing of weapons.

casemate wall A city or fortress enclosure
consisting of an outer and an inner masonry wall
braced by transverse masonry partitions, which
divide the interstitial space into a series of
chambers for fill or storage.

casement l.A window sash (ventilator, 2)
which swings open along its entire length; usu-
ally on hinges fixed to the sides of the opening
into which it is fitted; see casement window. 2.
A deep hollow molding, used chiefly in cornices.

casement adjuster A device for holding a case-
ment in any open position. Also see casement stay.

casement combination window A combi-
nation window, 2, one element of which is a
casement window.

casement door A French door.

casement fastener Same as casement stay.

casement hinge A hinge on which a casement, 1
is hung; also see butt casement hinge, close-up
casement hinge, extension casement hinge.

casement stay In a casement window, a bar
used to hold a casement, in any of several fixed,
open positions. Also see peg stay.

casement ventilator A casement, 1, which
opens like a door, supported on hinges, pivots, or
friction hinge mechanisms.

casement window A window having at least
one casement, 1; may be used in any combina-
tion with fixed lights.

casement window

casement sash Same as casement window,
caserne Same as barracks.

case mold A shell made of plaster to hold vari-
ous parts of a plaster mold in proper position;
also used to prevent distortion when pouring
gelatin or wax molds.

case steel The outside skin on steel produced
by case-hardening.

casework The aggregate assembled parts
(including framework, finish, doors, drawers,
etc.) which make up a case or cabinet.

cash allowance An amount established in the
contract documents for inclusion in the contract
sum to cover the cost of prescribed items not
specified in detail, with provision that variations
between such amount and the finally deter-
mined cost of the prescribed items will be
reflected in change orders appropriately adjust-
ing the contract sum.

cashel In Ireland, an enclosing wall of rough
stone, once intended as defensive work for a
church or for several sacred buildings; a caher.

casing 1. The exposed trim molding, framing, or
lining around a door or window; may be either
flat or molded. 2. Finished millwork, of uniform
profile, which covers pipes or encases a structural
member such as a post or beam. 3. A pipe section

179

casing bead

casing, 1

used to line a hole; may be driven, drilled, or
dropped into place; also called a shell. 4. Of a
pump, the housing that encloses the impeller.

casing bead A bead applied to edges of a plas-
ter surface to provide a stop or a separation
between two dissimilar materials.

casing-bead doorframe A doorframe having
a metal casing bead which serves as a ground for
plastering.

casing knife In paperhanging, a knife used to
trim wallpaper around casings, at moldings, base-
boards, etc.

casing nail A slender nail with a small, slightly
flared head used for finishing work.

pmc

casing nail

casing-off The elimination of the frictional
forces between a portion of a pile, 1 and the sur-
rounding soil by the use of a sleeve between the
pile and the soil.

casino 1. A clubhouse or public room, esp. used
for gambling. 2. A clubhouse or public room used
for dancing. 3. A summerhouse or lodge; a retreat.

Cassel brown See Vandyke brown.

cassoon A deep panel or coffer in a ceiling or
soffit.

cast glass Glass which is shaped by pouring
molten glass into a mold.

cast, staff In plastering, a shape, usually decora-
tive, made in a mold and then fastened in place.

castable refractory A packaged, dry mixture
of hydraulic cement (generally calcium alumi-
nate cement) and specially selected and pro-
portioned refractory aggregates which, when
mixed with water, produces refractory concrete
or mortar.

castellated 1. Bearing the external fortification
elements of a castle, in particular, battlements,
turrets, etc. 2. Ornamented with a battlement-
like or crenelated pattern.

castellated block A concrete block having a
vertical, ribbed, decorative facing.

castellum A reservoir, often of architectural
nature, at the end of an aqueduct, for distribut-
ing the water into various channels.

casting See founding.

casting bed A mold, often constructed of ply-
wood or fiberglass, which is used to give a desired
shape to poured concrete.

casting plaster A finely ground plaster with
special additives; used in casting work. The addi-
tives produce hardness and control shrinkage or
expansion.

cast-in-place concrete, in situ concrete
Concrete which is deposited in the place where
it is required to harden as part of the structure, as
opposed to precast concrete.

cast-in-place pile A concrete pile which is
concreted either with a casing or without a cas-
ing at its permanent location, as opposed to a
precast concrete pile.

cast-in-situ concrete Same as cast-in-place
concrete.

cast iron An iron alloy, usually including car-
bon and silicon; a large range of building prod-
ucts are made of this material by pouring the
molten metal into sand molds and then machin-
ing. Has high compressive strength, but low
tensile strength.

cast iron: soil pipe

cast-iron architecture In building construc-
tion, cast iron used in combination with wrought

180

cathead

iron for the framing of commercial buildings
and for the components of cast-iron fronts;
used primarily before the advent of steel-frame
construction. Usually characterized by: prefabri-
cated cast-iron components, repetitive modules,
and large windows, in contrast to earlier masonry
facades in which large windows were impractical
because they weakened the wall into which they
were set.

cast-iron boiler A boiler furnished in sections
of cast iron, usually assembled at the place of
installation; the capacity of the boiler may be
increased by adding more sections.

cast-iron front A load-bearing facade com-
posed of prefabricated parts, commonly used on
commercial buildings ca. 1850-1870.

cast-iron lacework Mass-produced decora-
tive ironwork of intricate design, formed by the
casting process and therefore relatively inexpen-
sive compared with wrought-iron work.

cast-iron pipe, cast-iron soil pipe A
pipe fabricated of an iron alloy containing
carbon and silicon; usually lined with cement
or coal-tar enamel and coated externally with
one of a variety of materials to reduce corro-
sion by soils; known technically as gray cast-
iron pipe.

cast-iron register See mantel register.

cast-iron stove See Franklin stove.

castle A stronghold; a building or group of build-
ings intended primarily to serve as a fortified post;
a fortified residence of a prince or nobleman. Also
see concentric castle.

castlery The area around a castle that is subject
to its domination.

cast molding A molding of plaster, cement, or
other such material which is cast in a mold in
sections and set in place after it has hardened.

castrum An ancient fortified town, castle, or
fort.

cast staff In plastering, a shape, usually deco-
rative, made in a mold and then fastened in
place.

cast stone See artificial stone.

CAT. On drawings, abbr. for "catalog."

cat A roll of straw and clay; used as filling
between timbers in a wall.

catabasis, catabasion See katabasis.

catacomb Underground passageways used as
cemeteries, with niches for sarcophagi or smaller
ones for cinerary urns.

catacumba The atrium or courtyard of a basili-
can church.

catafalque A draped and canopied stage
or scaffold, usually erected in a church, on
which is placed the coffin or effigy of a deceased
person.

catalyst l.A substance which accelerates a
chemical reaction but appears to remain
unchanged itself. 2. A hardener that accelerates
cure of adhesives either with or without heat.
Used primarily with synthetic resins.

catalytically-blown asphalt A blown asphalt

produced by using a catalyst during the blowing
process.

cat-and-clay chimney Same as stick-and-clay
chimney.

catch A device for fastening a door or gate; usu-
ally opened manually from one side only.

catch basin A reservoir, esp. for catching and
retaining surface drainage over a large area, in
which sediment may settle.

catch drain A drain running along sloping
ground to catch and convey the water flowing
over the surface.

catchment area Same as catch basin.

catch pit Same as catch basin.

catch platform A platform or other con-
struction projection from the face of a building,
from which it is supported; used to protect indi-
viduals and property from falling debris during
construction.

catena d'acqua In landscape architecture,
water which flows over a series of relatively nar-
row steps, forming a "staircase of water."

catenary The curve formed by a flexible cord
hung between two points of support.

catenary arch An arch which takes the form
of an inverted catenary.

catenated Decorated by a chain-like motif.

caterpillar Same as crawler tractor.

catface A rough depression, flaw, or blemish in
a plaster finish coat.

cathead A notched wedge placed between two
formwork members meeting at an oblique angle.

181

cathedra

cathedra The bishop's throne, set at the end of

the apse in Early Christian churches.

cathedra

cathedral The home church of a bishop, usu-
ally the principal church in a diocese.

cathedral glass Translucent sheet glass which
is unpolished.

cathedral precinct The grounds immediately
surrounding a cathedral.

Catherine-wheel window A round window
with radial mullions. A rose window, wheel
window.

cathetus The axis of a cylinder, esp. the axial
line passing through the eye of an Ionic
volute.

cathodic corrosion Same as galvanic corrosion.

catholicon See katholikon.

cathodic protection, electrolytic protection
A method of protecting a ferrous metal struc-
ture, which is embedded in water or moist soil,
from corrosion due to galvanic action; usually by
attaching it to a metal rod which is more elec-
tronegative than the structure, or by counteract-
ing the current which is the source of corrosion
by another one (in the opposite direction)
which just balances it.

cation-exchange softening The softening
of water by the removal of dissolved ionic con-
taminants in hard water (such as scale-forming
magnesium and calcium ions) and their
replacement with sodium ions, which are more
soluble.

cat ladder, duckboard, gang boarding,
roof ladder A plank with a series of small
strips nailed across it; hung on a sloping roof

cathedral: plan of Wells Cathedral. A, apse; B, altar; D, E,
eastern transept; F, G, western transept; H, central tower; I, J,
western towers; K, north porch; L, library; M, western door-
way; N, N, western side doors; O cloister yard; P, Q, north and
south aisles of choir; S , S , east and west aisles of transept; T,
U, north and south aisles of nave; R, R, chapels; V, rood
screen; W, altar of lady chapel

under repair to provide a footing for workmen
and to protect the surface.
cat's eye A pin knot smaller than l A in. (0.6 cm)
in diameter.

catshead An ornament consisting of an ani-
mal-like head, similar to a beakhead.

182

caustic etch

*m*m

catshead

catslide 1 . The long sloping roof at the rear of a
saltbox or catslide house. 2. The term used in
southern US for a saltbox house.

catslide house A commonly used term in
southern regions of the US for a saltbox house.

catstep See corbiestep.

CATW On drawings, abbr. for catwalk.

catwalk A narrow fixed walkway providing
access to an otherwise inaccessible area or to light-
ing units, light bridges, etc.; used above an excava-
tion, around a high building, above the ceiling of
an auditorium or theater, or around a stagehouse.

catstone Same as barstone.

caul A flat sheet of metal or wood used as a pro-
tective layer of plywood, particleboard, fiber-
board, etc., during the forming, pressing, and
shaping operations.

cauliculus, caulicole Any one of the orna-
mental stalks rising between the leaves of a
Corinthian or Composite capital, from which the
volutes spring.

caulis One of the main stalks of leaves which
spring from between the acanthus leaves of the
second row on each side of the typical Corinthian
capital, and which are carried up to support the
volutes at the angles.

caulk To fill a joint, crack, etc., with caulking.

caulked joint A type of joint used for cast-iron
pipe having hub-and-spigot ends. After the spigot-
end of one pipe is placed inside the hub-end of the
other, a rope of oakum or hemp is packed into the
annular space around the spigot end until the
packing is about 1 inch (2.5 cm) below the top.

KSWWF"-

ii C>Ltf D l*TTJ
AMlULAN SPAtt

caulked joint

Then molten lead is poured into the annular space
on top of the rope. Finally, the lead is pounded far-
ther into the joint with a caulking iron.

caulked rivet A rivet which has not been
properly driven so as to fit tightly in the hole,
but to which a seeming tightness has been given
by turning the edge of the head under with a
cold cut or similar tool.

caulking, calking l.A resilient mastic com-
pound, often having a silicone, bituminous, or
rubber base; used to seal cracks, fill joints, prevent
leakage, and/or provide waterproofing; also see
caulking compound. 2. Another term for cogging.

caulking cartridge An expendable container
made of plastic, fiberboard, or metal; filled with
caulking compound, for use in a caulking gun. A
common type is 2 in. (5 cm) in diameter, approx.
8 in. (20 cm) long, and fitted with a plastic nozzle.

caulking compound A soft putty-like mate-
rial intended for sealing joints in buildings and
other structures, preventing leakage, or provid-
ing a seal at an expansion joint; usually available
in two consistencies: "gun grade," for use with a
caulking gun, and "knife grade," for application
with a putty knife.

caulking ferrule A ferrule, usually of brass,
which is caulked.

caulking gun A device for applying caulking
compound by extrusion. In a hand gun, the
required pressure is supplied mechanically by
hand; in a pressure gun, the pressure required
usually is greater and is supplied pneumatically.

caulking recess In plumbing, a recess (or
counterbore) in the back of a flange into which
lead can be caulked, for water pipe connections
and the like.

causeway l.A paved road or passage raised
above surrounding low ground. 2. Such a passage
ceremonially connecting the valley temple with
the pyramid in Egyptian architecture.

caustic dip The immersion of metal in a chem-
ical solution for cleaning purposes.

caustic embrittlement A type of embrittle-
ment in the metal at joints and the ends of tubes in
steam boilers; due to the chemical composition of
the boiler water; may lead to failure of the metal.

caustic etch, frosted finish A decorative
matte texture produced on aluminum alloys by
an etching treatment in an alkaline solution,
generally caustic soda.

183

caustic lime

caustic lime See lime.

cavaedium 1 . An inner courtyard in a Roman
house. 2. An atrium.

cavalier 1 . A raised portion of a fortress for
commanding adjacent defenses or for the place-
ment of weapons. 2. A small tower on the ridge
of a double-pitched roof.

cavasion A term, used many years ago, for an
excavation for the foundation of a building.

cavea The semicircular, tiered seating area of an
ancient (esp. Roman) theater.

cavel Same as kevel.

cavetto, gorge, hollow, throat, trochilus

A hollow member or round concave molding
containing at least the quadrant of a circle, used
in cornices and between the tori of bases, etc.
Erroneously called "scotia," which has a noncir-
cular curvature.

examples of a cavetto

cavetto cornice See Egyptian gorge.

cavil Same as kevel.

cavitation A phenomenon in the flow of water

consisting in the formation and the collapse of

cavities in water.
cavitation damage The pitting of concrete

caused by implosion (collapse) of bubbles in

flowing water.
cavity barrier Same as fire stop.
cavity batten A piece of wood placed within a

cavity wall during construction to catch mortar

droppings.
cavity fill A material placed in the air space in

a hollow or double wall or in a floor-ceiling

assembly to improve its sound- or heat-insulation

qualities.

cavity flashing A continuous sheet of water-
proofing material which is installed across the
gap of a cavity wall.

WEEP
HOLES

FLASHING

cavity flashing

cavity tie See cavity wall tie.

cavity tray A British term for cavity flashing.

cavity wall, hollow masonry wall, hollow
■wall An exterior wall, usually of masonry,
consisting of an outer and inner withe separated
by a continuous air space, but connected
together by wire or sheet-metal ties. The dead
air space provides improved thermal insulation.

cavity wall

cavity 'wall tie A rigid, corrosive-resistant
metal tie which bonds two withes of masonry.

cavity vent An opening in a stone veneer wall
to permit air and moisture from inside the cavity
wall to escape to the exterior.

cavo-rilievo, cavo-relievo See sunk relief.

cayola A hard plaster or stucco, similar to arga-
masa.

184

ceiling joist

CB Abbr. for catch basin.

CB1S Abbr. for "center beam one side."
CB2S Abbr. for "center beam two sides."
CBM Abbr. for "Certified Ballast Manufacturers

Association."
CBR Abbr. for California bearing ratio.
C/B ratio, saturation coefficient The ratio
of the weight of water absorbed by a masonry
unit during immersion in cold water to weight
absorbed during immersion in boiling water; an
indication of the probable resistance of brick to
freezing and thawing.
c»c Abbr. for "center-to-center."
cc, CC Abbr. for "cubic centimeter."
C-clamp A steel clamp, shaped like the letter
C; used to hold, under pressure, two materials
placed between the top of the open end of the C
and a flattened end of a screw shaft which is
threaded through the other end of the C.

C-clamp

CCTV Abbr. for "closed-circuit television."
CCTV surveillance system See closed-circuit
TV surveillance system.

CCW On drawings, abbr. for "counter-clockwise."

cd Abbr. for candela.

cedar A durable softwood generally noted for

decay resistance; includes western red cedar,

incense cedar, eastern red cedar.

cedro In Spanish Colonial architecture, one of
many unsplit peeled, relatively straight, red
cedar saplings supported by vigas; used in ceiling
construction.

ceil l.To provide with a ceiling. 2. To provide
with a wainscot finish; to sheathe internally.

ceiling The overhead surface of a room, usually
a covering or decorative treatment used to con-
ceal the floor above or the roof.

ceiling area lighting Lighting in which the
entire ceiling acts as one large luminaire, as, for
example, a luminous ceiling.

ceiling beam Same as ceiling joist.

ceiling binder An intermediate support for
ceiling joists.

ceiling cable distribution system A cable
distribution system in which cable is run
through the space between a suspended or false
ceiling and the structural floor above it.

ceiling cable distribution system

ceiling cornice Same as cove molding.

ceiling diffuser, ceiling outlet l.Any air
diffuser (usually round, square, rectangular, or
linear) which is located in the ceiling; used to
provide a horizontal distribution pattern of air
over a zone occupied by people.

ceiling fan A ceiling-mounted air-moving
device that is characterized by several revolving
blades (commonly three to five) which are com-
paratively large and slow-moving; usually hung
so that it directs the air downward; relatively
quiet in operation because of its low speed.

ceiling fitting Same as surface-mounted lumi-
naire.

ceiling flange Same as escutcheon, 2.

ceiling floor The framework for a ceiling
beneath, but not for the floor above.

ceiling hanger A hanger, 1 for supporting a
room's ceiling, usually by means of rods or wires.
An elastomer or metal spring may be incorpo-
rated into the suspension to improve its sound
isolation from the structure above; see illustra-
tion under resilient hanger.

ceiling height The clear vertical distance from
the surface of the finished floor to the ceiling
above it.

ceiling hook A hook having a wood screw
formed in its base. (See illustration p. 186.)

ceiling joist 1. Any joist which carries a ceiling.
2. One of several small beams to which the ceiling
of a room is attached. They are mortised into the

185

ceiling light

»»

ceiling hook

JOIST

ceiling joists carrying an acoustical ceiling

sides of the binding joists, nailed to the underside
of these joists, or suspended from them by straps.

ceiling light A borrowed light, 1, horizontally
located in a ceiling to provide light below.

ceiling medallion, ceiling ornament, ceil-
ing rose A ceiling ornament, usually cast in
plaster; often a luminaire or chandelier is hung
from its center; see medallion, 2.

ceiling outlet l.A ceiling diffuser. 2. A small
metal box, mounted at ceiling level, in which
electric conductors terminate; used to support a
lighting fixture or other ceiling-mounted electric
appliance.

ceiling plenum In an air-conditioning system,
the space between a hung ceiling and the under-
side of a floor slab above, where this space is used
as a plenum for return air.

ceiling ratio In illumination engineering, the
ratio of the luminous flux which reaches the ceil-
ing directly to the upward component of the flux
provided by a luminaire.

ceiling rose See ceiling medallion.

ceiling sound transmission In a suspended
ceiling construction, the transmission of sound
between adjoining rooms by way of the path con-
sisting of the ceiling of each room and the contin-
uous plenum over, and common to, both rooms.

ceiling sound transmission class, ceiling
STC A single-number rating of the sound-
insulating value of a suspended ceiling between
adjacent rooms.

ceiling sprinkler A fire sprinkler (head) of
special design, intended for installation in ceil-
ings; includes sprinklers of the recessed, flush,
and concealed types.

ceiling STC Same as ceiling sound transmis-
sion class.

ceiling strap A strip of wood, nailed to the
underside of floor joists or rafters, from which a
ceiling is suspended or fastened.

ceiling strut An adjustable vertical member
which extends from the head of a doorframe to
construction above; used to hold the frame in a
fixed position prior to wall construction; also see
strut guide.

ifik

CEILING STRUT

STRUT
GUIDE

ceiling strut

ceiling suspension system A system of
metal members designed to support a suspended
ceiling, typically an acoustical ceiling. Also may
be designed to accommodate lighting fixtures or
air diffusers.

ceiling suspension system: AT, acoustical tile; CC, carrying

channel; CR, cross runners; H, hanger wire; MR, main runner;

S, spline

186

cellular floor

ceiling switch Same as chain-pull switch.
ceilure See celure.

celature Engraved, chased, or embossed deco-
ration on metal.

cell l.See core. 2. A single small cavity sur-
rounded partially or completely by walls. 3. A
segment of a ribbed vault. 4. The small sleeping
apartment of a monk or a prisoner. 5. In electri-
cal systems, a single raceway of a cellular or
underfloor duct system. 6. In electrical batteries,
a single voltage-producing component used in
series with other similar components to provide
the desired output voltage.

cella, naos The sanctuary of a classical temple,
containing the cult statue of the god.

* n

: I

s. i

s^r^-y

cella E , site of cult statue A

cellar 1. A room (or several rooms, or the entire
basement floor) that is partially or entirely
below grade; relatively cool in the summer and
above freezing in the winter; often used as stor-
age space; provides some thermal insulation air-
space between the ground or concrete slab and
the flooring of the wood floor above. 2. That
part of a building having at least half of its clear
height below grade. Also see earth cellar, root
cellar, storm cellar, basement.

cellar bulkhead, cellar cap Same as bulk-
head, 4.

cellar door A bulkhead, 4, often sloping or
nearly horizontal.

cellar hole The excavation for a cellar or the
open remains of a cellar.

cellarino In the Roman or Renaissance Tuscan
or Doric orders of architecture, the neck or
necking beneath the ovolo of the capital.

cellar rot Same as wet rot.

cellar sash A window sash set into the founda-
tion wall of a building, usually just below the
horizontal member or surface that provides bear-
ing and anchorage for the wall above.

cellarway Passage to or through one or more
cellars.

cellula 1. In ancient Rome, a small sanctuary in
the interior of a small temple. 2. Any small
chamber or storeroom.

cellular block A concrete masonry block
which has uniformly distributed pores through-
out its mass.

cellular brick (Brit.) A brick or block in
which holes, closed at one end, exceed 20% of
the volume.

cellular cofferdam A self-sustaining coffer-
dam fabricated of interlocking steel sheet piling;
has separate inside and outside walls.

cellular concrete, aerated concrete A
light-weight product consisting of portland
cement, cement-silica, cement-pozzolan, lime-
pozzolan, or lime-silica pastes, or pastes contain-
ing blends of these ingredients and having a
homogeneous cell structure, produced by gas-
forming chemicals or foaming agents.

cellular construction Construction with con-
crete elements in which part of the interior
concrete is replaced by voids.

cellular-core door See mesh-core door.

cellular floor A floor having hollow open-
ings in it that provide ready-made raceways for

cellular floor

187

cellular framing

distributing wiring for telecommunications

and electric power.
cellular framing See box frame, 1.
cellular glass See foam glass.

cellular material Any material that contains
many cells (either open or closed, or both) dis-
persed throughout the mass.

cellular office A large floor space that is divided
into a number of individual offices by perma-
nent walls, in contrast to an open-plan office.

cellular plastic A plastic containing numerous
cells disposed uniformly throughout its mass.

cellular polystyrene An insulation com-
posed principally of a polymerized styrene resin
which has been processed to form a rigid foam
having a closed-cell structure.

cellular raceway A hollow space, in a modu-
lar floor system, suitable for use as a raceway for
electric conductors.

cellular rot Same as wet rot.

cellular rubber A rubber product containing
cells that are either open and interconnecting or
closed and not interconnecting.

cellular striation In a cellular material, such
as plastic, a layer of cells that differ greatly
from the characteristic cell structure of the
material.

celluloid A relatively tough thermoplastic
material made from plasticized cellulose nitrate
with camphor; inflammable, easily molded,
readily dyed, not light-stable.

cellulose A naturally occurring polysaccharide
made up solely of glucose units and found in
most plants; the main constituent of dried
woods, jute, flax, hemp, ramie, etc.; cotton is
almost pure cellulose; used in the manufacture of
a wide variety of synthetic building materials.

cellulose acetate A material of the ester fam-
ily derived by conversion of cellulose; used in
the production of synthetic lacquers, coatings,
plastics, and thermal insulation.

cellulose acetate butyrate (CAB) plastic
A plastic compound of cellulose acetate butyrate
ester and plasticizer and other ingredients.

cellulose enamel Lacquer made with nitro-
cellulose. Also see lacquer.

cellulose fiber tile An acoustical tile formed
of cellulose fiber.

cellulose lacquer A lacquer having a cellu-
lose derivative base.

cellulose nitrate A material formed by the
reaction of cellulose fibers with nitric and sulfu-
ric acids. Those with lower nitrogen content are
used as binders in lacquers and are very inflam-
mable. A high nitrogen content results in nitro-
cellulose, an explosive.

cellure See celure.

Celsius scale Same as centigrade scale.

Celtic cross A cross with a long vertical shaft
and short horizontal arms, and with a circle
struck from their intersection, joining all four.

Celtic cross

celure, ceilure, cellure A decorative ceiling,
esp. over the chancel, in medieval church archi-
tecture or derivatives. 2. A paneled canopy
above an altar or crucifix.

CEM On drawings, abbreviation for cement.

cem ab Abbr. for cement-asbestos board.

cement 1 . A material or a mixture of materials
(without aggregate) which, when in a plastic
state, possesses adhesive and cohesive proper-
ties and hardens in place. Frequently, the term
is used incorrectly for concrete, e.g., a "cement"
block for concrete block. See also portland
cement. 2. A calcined combination of lime-
stone and clay, combined with an aggregate
that reacts chemically when water is added;

188

cement-wood floor

after this reaction occurs, the mixture hardens
in place as it dries, resulting in a stonelike
material. Although the ancient Romans devel-
oped a cement that could harden under water
(called hydraulic cement), there was little infor-
mation in modern times on how to produce
such a cement until the mid- 1 700s when exper-
iments in England led to the development of a
cement that could set quickly, in or out of water.
Also see hydraulic cement, Portland cement,
Roman cement, water cement.

cement-aggregate ratio The ratio, by weight
or volume, of cement to aggregate.

cement-asbestos board A dense, rigid, non-
combustible board containing a high proportion
of asbestos fibers which are bonded with port-
land cement; highly resistant to weathering; also
called asbestos-cement board.

cementation The setting of a cement.

cement bacillus See ettringite.

cement block See concrete block.

cement brick Brick fabricated from a mixture
of cement and sand; molded under pressure and
steam-cured at a temperature of 200°F (93 °C);
used behind face brick where it will not be
exposed to acid or alkaline conditions.

cement clinker See clinker, 1.

cement-coated nail A nail which is coated
with cement to increase its holding power.

cement content, cement factor The quan-
tity of cement contained in a unit volume of
concrete or mortar, preferably expressed as
weight, but frequently given as bags of cement
per cubic yard of concrete, e.g., a 6'/2-bag mix.

cemented soil Soil in which the particles are
held together by a chemical agent.

cement factor See cement content.

cement fillet, weather fillet Mortar which
provides a weathertight seal in a corner between
roofing slates and a wall; used in place of flashing.

cement fondu Same as calcium alumina te
cement.

cement gel A colloid comprising the largest part
of the porous mass of mature hydrated cement
paste.

cement gravel Gravel bound into a mass by
clay, calcium carbonate, silica, or some other
binding agent.

cement grout See grout.

cement gun A device for applying cement
mortar as a spray; uses compressed air as the
propellant.

cementitious Having cementing properties.

cementitious material A material (with or
without an aggregate) that provides plasticity,
cohesive, and adhesive properties when it is
mixed with water — properties that are necessary
for its placement and formation into a rigid mass.

cementitious mixture A mixture of mortar,
concrete, or grout that contains hydraulic cement.

cement mixer See concrete mixer.

cement mortar A mixture of cement, lime,
sand, or other aggregates with water; used for
plastering over masonry or to lay blocks. The
lime adds plasticity and resistance to moisture.
Also see mortar.

cement paint, concrete paint l.A paint
consisting generally of white portland cement
and water, pigments, hydrated lime, water repel-
lents, or hygroscopic salts; usually applied over
masonry surfaces as a waterproofing. 2. A paint
formulated to be resistant to the alkali in the
cement surface over which it is applied.

cement paste A mixture of cement and water.

cement plaster 1 . Plaster with portland cement
as the binder; sand and lime are added on job.
Used for exterior work or in wet or high-humidity
areas. 2. In some regions, gypsum plaster.

cement rendering The application of a port-
land cement and sand mix over a surface; has
rather poor weather resistance.

cement rock, cement stone A clayey lime-
stone whose percentage composition of alumina,
lime, and silica is about that of cement; may be
used without the addition of other earth materials.

cement screed A screed of cement mortar.

cement slurry A mixture of cement and water,
still in the liquid state; injected into prepacked
aggregate or used as a wash over a surface.

cement stucco Same as stucco.

cement temper Portland cement used as an
additive in lime plaster to improve its strength
and durability.

cement-water paint Same as cement paint.

cement-wood floor A poured floor of a mix-
ture of portland cement, sand, and sawdust.

189

cemetery beacon

cemetery beacon In Europe in the 12th and
13th centuries, a model of a lighthouse having
an altar.

cem. fin. Abbr. for "cement finish."

CEM FL On drawings, abbr. for "cement floor."

CEM MORT On drawings, abbr. for cement
mortar.

CEM PLAS On drawings, abbr. for cement
plaster.

cen Abbr. for "center" or "central."

cenaculum In ancient Rome, a small informal
dining room, often on an upper story.

cenatio In ancient Rome, the formal dining
room in a house, sometimes even in a separate
annex.

cenotaph A monument erected in memory of
one not interred in or under it.

center l.The center ply in plywood. 2. The
core in a laminated construction. 3. Centering.
4. The center about which an arc of a circle is
drawn, equidistant from all points on the arc.

center bit A tool for boring holes in wood, held
by a brace; the cutting end consists of a sharp point
(or threaded center spur) for fixing the center of
the hole, a projecting scoring edge for marking the
circumference of the hole, and a sharp lip for cut-
ting away the wood inside the circumference.

center bit showing cutting end

center flower A molded plaster centerpiece.

center-gabled pediment A pediment on a

gable located at the center of a facade; may be
flush with the front wall or project forward from it.
center gutter Same as valley gutter.

center-hall cabin, central-hall cabin A

cabin having two rooms that are separated by a
hallway; often, there is an exterior chimney on
each end wall. Compare with dogtrot cabin and
saddlebag cabin.

center-hall plan In American Colonial architec-
ture, the floor plan of a house usually having two
rooms symmetrically situated on each side of a cen-
trally located hallway; a stair in the hallway leading
to the loft space above. Essentially a hall-and-parlor
plan with a hallway separating the two rooms.

HNING ROOM BEDROOM I

HALL

I L-L

PARLOR

center-hall plan

center-hung door, center-pivoted door A

door which is supported by and swings about a
pivot recessed in the floor at a point located on
the center line of the door's thickness; the door
may be of the single-swing or double-acting type.

center-hung sash A window sash hung on its
centers so that it swings about a horizontal axis.

centering A temporary structure upon which
the materials of a vault or arch are supported in
position until the work becomes self-supporting.

centering: two types

190

central mixer

centering rafter The common rafter, directly
adjacent to a hip rafter, that joins the longitudi-
nal member at the apex of a roof.

center line A line representing an axis of sym-
metry; usually shown on drawings as a broken line.

center- matched Said of tongue-and-grooved
lumber with its tongue-and-groove at the center
of the piece rather than offset as in standard
matched.

center nailing The nailing of slates (at a point
just above their middle) along a line which is
slightly above the head of the slates in the
course below.

center of gravity, center of mass A point
within a body such that, if the whole mass of the
body were concentrated there, the attraction of
gravity would remain the same.

center of mass See center of gravity.

center of twist See shear center.

center-opening door Same as biparting door.

centerpiece An ornament placed in the mid-
dle of something, as a decoration in the center of
the ceiling.

center pivot Of a door: a pivot having its
axis on the thickness center line of the door,
normally about 2 } A in. (7 cm) from the hinge
jamb.

center-pivoted door See center-hung door.

centerplank, heart plank Usually a quarter-
sawn hardwood board cut near the center of
a log.

center punch A hand-held punch consisting
of a steel rod, one end of which has a sharp
point; used to mark a point on metal, indicating
where a hole is to be drilled.

center punch

center rail The horizontal door rail which sep-
arates the upper and lower panels of a recessed
panel-type door; usually located at lock height.

centers See centering.

center shaft Of a revolving door, the vertical
shaft to which the wings are attached.

center stringer A string, 1, which is located
under a flight of stairs at its midpoint and which
supports its treads by cantilever action.

center-to-center, on center The distance
between the center line of one element, mem-
ber, part, or component (as a stud or joist) and
the center line of the next.

centi A prefix indicating division by 100.

centigrade The thermometer scale, divided
into 100 degrees, in which 0°C is the freezing
point of water and 100°C is the boiling point.

centigrade heat unit Same as pound-calorie.

centimeter In the metric system, a measure of
length equal to a hundredth part of a meter, or
0.3937+ in.; abbreviated cm; an inch equals
2.54 cm.

central air-conditioning system An air-
conditioning system in which the air is treated
by equipment at one or more central locations
outside the spaces served, and conveyed to and
from these spaces by means of fans and pumps
through ducts and pipes.

central air-handling unit An air-handling
unit in which treated air is distributed to a num-
ber of spaces by means of ductwork.

central fan system A mechanical system of
air conditioning in which air is treated by equip-
ment outside the area served and distributed by
means of ductwork.

central-hall plan, central-passage plan

Same as center-hall plan.

central heating system A system in which
heat is supplied to all areas of a building from a
central plant through a network of ducts or
pipes.

centralized HVAC system A heating, ven-
tilating, and air-conditioning system having
a single heating and/or cooling source for air
distribution.

centralized structure A building having all
its principal axes of equal length.

centrally located chimney, central chim-
ney An interior chimney, often massive in
size, located near the middle of a house, to pro-
vide heat for the entire house during the winter.

central-mixed concrete Concrete that is
completely mixed in a stationary mixer, from
which it is transported to the delivery point.

central mixer A stationary concrete mixer
from which the freshly mixed concrete is trans-
ported to the work.

191

central newel

central newel In a spiral stair, the column
around which the stairs are wound.

central pavilion A centrally located, prominent
projection from the facade of a monumental pub-
lic building or stately home; often two stories high
and domed, and architecturally accented by more
elaborate decorative elements.

central-plant refrigeration system A
refrigeration system in which the cooling
medium is distributed to remote locations from
a central location, generally containing multi-
ple refrigeration compressors and circulating
pumps.

central-services core In a high-rise building,
a central zone around which elevators, toilets,
stairs, and service shafts are located.

central station An office to which one or
more types of alarm systems in a building are
connected; operators monitor and provide
supervisory control of these systems; may be pro-
vided with direct lines to fire or police depart-
ments, or to other outside agencies.

centric load, concentric load A load which
passes through the centroid of the cross section
of a structural member and acts normal to the
cross section.

centrifugal compressor A compressor in
which compression is obtained by the use of a
centrifugal pump.

centrifugal fan A fan, within a scroll-type
housing, which receives air along the axis and
discharges it radially; may be either belt-driven
or connected directly to a motor.

centrifugal fan

centrifugally-cast concrete See spun con-
crete.

centrifugal pump A pump in which the pres-
sure is imparted to the fluid by centrifugal force
produced by a rotating impeller.

centring Same as centering.

centroid The point which may be considered
the center of a two-dimensional figure; the cen-
ter of gravity of an area.

centry -garth A burying ground or cemetery.

CEQ Abbr. for "Council on Environmental
Quality."

CER On drawings, abbr. for ceramic.

ceramic Any of a class of products, made of clay
or a similar material, which are subjected to a
high temperature during manufacture or use, as
porcelain, stoneware, or terra-cotta; typically a
ceramic is a metallic oxide, boride, carbide, or
nitride, or a mixture or compound of such
materials; hard, brittle, and an electrical insulator.

ceramic aggregate Ceramic products in lump
or fragment form, usually colored, used in mak-
ing ornamental concrete.

ceramic bond A bond between materials
which are exposed to temperatures approaching
the fusion point of the mixture, as a result of
thermochemical reaction between the materials.

ceramic coating An inorganic, essentially
nonmetallic protective coating on metal, suit-
able for use at or above red heat.

ceramic color glaze, ceramic glaze An
opaque, colored glaze of satin or gloss finish;
obtained by coating the clay body with a com-
pound of metallic oxides, chemicals, and clays,
either by spraying or by dipping, and then burn-
ing at high temperatures; the glaze is fused to the
body, making them inseparable.

ceramic-faced glass Glass which during the
heat-strengthening process has colored ceramic
frit permanently fused to one surface.

ceramic tile 1. A glazed, 2 burned-clay prod-
uct, having an impervious surface; widely used in
plumbing systems. 2. A ceramic mosaic, 2.

ceramic veneer An architectural terra-cotta
having a ceramic glazed surface; the dimensions
of its face are usually large compared with its

192

cesspool

thickness; the backside glazing is either scored or
ribbed, making it easier to attach the ceramic
veneer to a wall or other surface.

cercis The wedge-like or trapezoidal section of
seats between two of the stepped passageways in
a Greek theater.

ceroma In a Greek or Roman bath, a room
where bathers and wrestlers were anointed with
oil thickened with wax.

certificate for payment A statement from
the architect to the owner confirming the
amount of money due the contractor for work
accomplished or materials and equipment suit-
ably stored, or both.

certificate of compliance A document
issued by the responsible governmental authority
stating that all of a building, or any designated
portion thereof, complies with all provisions of
applicable codes, statutes, and regulations.

certificate of insurance A memorandum
issued by an authorized representative of an
insurance company stating the types, amounts,
and effective dates of insurance in force for a
designated insured.

certificate of occupancy A document issued
by governmental authority certifying that all or
a designated portion of a building complies with
the provisions of applicable statutes and regula-
tions, and permitting occupancy for its desig-
nated use. Also called an occupancy permit or a
certificate of use and occupancy permit.

certificate of substantial completion A

certified statement, prepared by an architect on
the basis of his inspection, (a) stating that the
work, 1, or designated portion thereof, is sub-
stantially complete and ready for occupancy for
its intended use; (b) establishing the date of sub-
stantial completion; (c) defining the interim
responsibilities of the owner and the contractor
for the provision of heat, maintenance, and
security, and for possible damage and insurance;
and (d) fixing the time within which the con-
tractor shall complete the items on the inspec-
tion list (see punch list).

certificate of title A certificate issued by the
appropriate land registration authority certifying
that the land in question is lawfully owned; it
describes the land and indicates any encum-
brances upon it.

certification A declaration in writing that a
particular product or service complies with a
specification or stated criterion.

certified A term indicating that a testing labo-
ratory, professional engineer, manufacturer, or
contractor has formally confirmed that a mate-
rial, device, or assembly of components conforms
to the requirements of the applicable code.

certified ballast A fluorescent lamp ballast
which adheres to performance standards set by
the Certified Ballast Manufacturers Association.

Certified Ballast Manufacturers Associa-
tion An independent organization of fluores-
cent lamp ballast manufacturers.

certified construction specifier A construc-
tion professional who, by experience and examina-
tion by the Construction Specifications Institute,
has been certified as being proficient in the knowl-
edge and art of preparing technical specifications
for the building construction process.

certified output rating Same as gross output.

certosa A monastery of the Carthusian monks,
esp. in Italy.

cesspit Same as cesspool.

cesspool 1. A lined and covered excavation in
the ground which receives the discharge of
domestic sewage or other organic wastes from a
drainage system, so designed as to retain the
organic matter and solids, but permitting
the liquids to seep through the bottom and
sides; also called a leaching cesspool or pervious
cesspool. 2. (Brit. ) A wooden box, usually lead-
lined, constructed in a roof or gutter, to collect
rainwater, which then passes to a downpipe.

cesspool

193

CF l.Abbr. for "cost and freight." 2.Abbr. for
"cooling fan."

cfm Abbr. for "cubic feet per minute."

CFR Abbr. for Code of Federal Regulations.

CG l.Abbr. for "coarse grain." 2. On drawings,
abbr. for "ceiling grille." 3. Abbr. for "corner
guard." 4. Abbr. for center of gravity.

CG2E Abbr. for "center groove two edges."

chafer house Old English term for ale house.

chaff house A subsidiary building used on a
farm to store fodder, such as corn husks, cut hay,
or the like.

chain A land surveyor's standard distance-
measuring device. Also see Gunter's chain.

chain block, chain fall, chain hoist A
tackle, fitted with an endless chain for hoisting a
heavy load by hand; often suspended from an
overhead track.

chain bolt At the top of a door, a spring bolt
which is actuated by a chain attached to it.

chain bond Masonry construction which is
bonded together by an embedded iron bar or
chain.

chain bucket loader A bucket-wheel exca-
vator in which the buckets are on a roller chain.

chain course A bond course formed by stone
headers which are held together by cramps.

chain door fastener A device attached to a
door and its jamb which limits the door opening
to the length of the chain.

chain door fastener

chain-driven machine A machine con-
nected by chain to a reversible motor or engine;
for example, a chain-driven elevator.

chaines 1. A type of wall decoration used in
17th century French domestic architecture; con-
sists of vertical bands of rusticated masonry

which divides the facades into panels or bays. 2.
Same as quoin.

chain fall See chain block.

chain hoist See chain block.

chaining In surveying, the measuring of a dis-
tance by use of a chain or tape.

chaining pin, surveyor's arrow, taping
arrow, taping pin A metal pin used in sur-
veying for marking taped measurements on the
ground.

chain intermittent fillet weld Two lines of
intermittent fillet welds on a joint, one line
being approximately opposite the other.

chain intermittent fillet weld

chain link fence A fence made of heavy steel
wire fabric (usually coated with zinc, or the like)
which is interwoven in such a way as to provide
a continuous mesh without ties or knots, except
at the selvage; the wire fabric is held in place by
metal posts.

chain molding A molding carved with a rep-
resentation of a chain.

chain-pipe vise A portable vise used to hold
pipe in the jaw by means of a chain.

chain pipe wrench, chain tongs A plumber's
wrench for turning pipe, consisting of a lever arm
which has sharp teeth that engage the pipe and a
short, adjustable chain which is wrapped around
the pipe and holds the pipe securely.

chain pipe wrench

chain-pull switch An electric switch, used in
interior wiring, which is operated by pulling a
chain or cord; usually mounted on the ceiling.

194

chalk line

chain pump A pump consisting of an endless
chain, fitted at intervals with disks, which
moves through a pipe; used to raise sludge.

chain riveting Riveting in which the rivets are
set in parallel adjacent rows along the seam and
are not staggered.

chain riveting

chain saw A power-driven saw, usually hand-
held, for cutting wood; a protruding arm carries
an endless chain, into which the cutting teeth
are set.

chain saw

chain scale A draftman's scale or an engineer's
scale which is graduated in inches, which are
further subdivided by 10 and multiples of 10.

chain timber A large bond timber.

chainwire The fabric from which a chain link
fence is woven.

chair 1. A bar support. 2. A metal frame, built
into a thin partition wall and the floor to sup-
port a sanitary fixture (such as a washbasin or
water closet) clear of the floor. 3. A device used
to support reinforcing bars.

chair board Same as chair rail.

chair house Same as cart house.

chairlift An electrically-operated lift for con-
veying a single passenger, who is seated in a
chair, up or down the incline of a flight of
stairs; in a private residence from one floor
level to the next, or in a commercial building
to meet the conditions of the Americans with
Disabilities Act.

chair rail A horizontal strip usually of wood,
affixed to a plaster wall at a height which pre-
vents the backs of chairs from damaging the wall
surface.

chair rail cap See cap, 3.

chaitya A Buddhist or Hindu sanctuary, shrine,
or temple.

chaitya hall A hall of worship adjacent to a
Buddhist monastery.

chalcedony A submicroscopic variety of
fibrous quartz, generally translucent and con-
taining variable amounts of opal; reacts with
alkalies in portland cement.

chalcidicum, chalcidic 1. A portico, or hall
supported by columns, or any addition of like
character connected with any ancient basilica;
hence a similar addition to a Christian church.
2. In a Christian basilica, the narthex. 3. In
ancient Roman architecture, a building for judi-
cial functions.

chalcidium A committee room off the main
part of an ancient Roman lawcourt (basilica).

chalet 1 . A timber house especially found in the
Alps, distinguished by the exposed and decora-
tive use of structural members, balconies, and
stairs. Upper floors usually project beyond the
stories below. 2. Any building of similar design.
See Swiss cottage architecture.

chalk A soft limestone, usually white, gray, or
buff in color, composed chiefly of the calcareous
remains of marine organisms.

chalkboard A marking surface, primarily
for use with chalk, which is cleanable and
reusable.

chalkboard trim A chalkboard frame, operat-
ing hardware, and accessories.

chalked See chalky.

chalking The formation of a powdery surface
condition from the disintegration of a binder or
elastomer, as in a coating such as cement paint.
The binder is decomposed and the pigment is
loosely bound on the surface and resembles
chalk when the finger is rubbed over it; caused
by weathering or an otherwise destructive
environment.

chalk line l.A light cord rubbed with
chalk and stretched over a surface to mark a

195

chalky

chalk line

straight line. 2. A line so marked. 3. Same as
fat lime.

chalky, chalked Descriptive of the condition
of a porcelain enameled surface that has lost its
natural gloss and become powdery.

CHAM On drawings, abbr. for chamfer.

chamber 1 . A room used for private living, con-
versation, consultation, or deliberation, in con-
trast to more public and formal activities. Also see
bedroom, boudoir, cabinet, closet, den, parlor,
solar, study. 2. A room for such use which has
acquired public importance, e.g., the senate
chamber, an audience chamber. 3. (Brit., pi.) A
suite of rooms for private dwelling. 4. (pi. ) A suite
of rooms for deliberation and consultation (juris-
tic). 5. A space equipped or designed for a special
function, mechanical or technological, e.g., a tor-
ture chamber, a combustion chamber.

chamber story In a house, a floor completely
occupied by bedrooms; also called chamber floor.

chamber test A fire test for floor coverings,
developed by Underwriters' Laboratories, Inc.,
in which speed and distance of flame spread are
measured.

chamber tomb See passage grave.

chambered hall A house, having a one-room
plan, which is two stories in height.

chambranle A structural feature, often orna-
mental, enclosing the sides and top of a doorway,
window, fireplace, or similar opening. The top
piece or lintel is called the transverse and the side
pieces or jambs the ascendants.

chambrel An obsolete term for gambrel.

chamfer l.A bevel or cant, such as a small
splay at the external angle of a masonry wall. 2.
A wave molding. 3. A groove or furrow. 4. An
oblique surface produced by beveling an edge or
corner, usually at a 45° angle, as the edge of a
board or masonry surface.

chamfer, 4

chamfer bit A bit for beveling the upper edge
of a hole.

chamfered rustication Rustication in which
the smooth face of the stone parallel to the wall
is deeply beveled at the joints so that, where two
stones meet, the chamfering forms an internal
right angle.

chamferet, chamfret l.A hollow chamfer.
2. A hollow channel or gutter.

chamfer plane A carpenter's plane esp. used
for beveling edges; has a V-groove along the bot-
tom or adjustable guides to facilitate the cutting
of chamfers.

chamfer stop 1 . Any ornamentation which
terminates a chamfer. 2. A stop chamfer.

chamfer stop

chamfer strip A cant strip.

champ A defined surface ready for carving.

196

channel beam

champfer Same as chamfer.
chancel The sanctuary of a church, including
the choir; reserved for the clergy.

chancel aisle The side aisle of a chancel in a
large church; it usually passes around the apse,
forming a deambulatory.

chancel arch An arch which, in many churches,
marks the separation of the chancel or sanctuary
from the nave or body of the church.

chancel arc

chancellery, chancellory l.A chancellor's
office or a building containing one. 2. The offi-
cial premises of a diplomatic envoy abroad.

chancel rail The railing or barrier in place of a
chancel screen by which the chancel is sepa-
rated from the nave.

chancel screen Screen dividing the chancel
from the nave.

chancery A building or suite of rooms designed
to house any of the following: a lawcourt with
special functions, archives, a secretariat, a chan-
cellery.

chandelier A luminaire suspended from the
ceiling; usually ornate or branched with the lamps
visible.

chandlery, chandry A storage room for light-
ing supplies and devices, required before gas or
electricity was available.

chandry See chandlery.

change In building construction, an authorized
alteration or deviation from the design or scope
of work as originally defined by the contract
documents.

change of use An alteration in the permitted
use of an existing building; such a change may
result in the imposition of other provisions of
the applicable code, for example, those govern-
ing means of egress from the building.

change order A written order to the contrac-
tor signed by the owner and the architect, issued
after the execution of the contract, authorizing a
change in the work or an adjustment in the con-
tract sum or the contract time as originally
defined by the contract documents; may add to,
subtract from, or vary the scope of work. A
change order may be signed by the architect
alone (provided he has written authority from
the owner for such procedure and that a copy of
such written authority is furnished to the con-
tractor upon request), or by the contractor if he
agrees to the adjustment in the contract sum or
the contract time.

changeover point The temperature at which
the thermal transmission loss to the outside of a
building equals the heat gain in the interior, so
that cooling or heating is not required.

changes in the work Changes ordered by the
owner consisting of additions, deletions, or
other revisions within the general scope of the
contract, the contract sum and the contract time
being adjusted accordingly. All changes in the
work, except those of a minor nature not involv-
ing an adjustment to the contract sum or the
contract time, should be authorized by change
order. Also see field order.

channel l.A structural or rolled steel shape
used in steel construction. 2. A decorative
groove, in carpentry or masonry. 3. An enclo-
sure containing the ballast, starter, lamp holders,
and wiring for a fluorescent lamp, or a similar
enclosure on which filament lamps (usually
tubular) are mounted.

channel, 1

channel bar See channel iron.

channel beam A structural member having a
U-shaped cross section.

197

channel block

channel block A hollow concrete masonry
unit with portions depressed to form a continu-
ous channel for reinforcing steel and grout.

channel clip 1. In a ceiling suspension system,

a metal clip which is hung from a channel and to
which a perforated metal pan is attached. 2. A
special fastener made of light-gauge sheet metal
or wire for the attachment of gypsum lath, or the
like, to steel channels.

CHANNEL
CLIP

CHANNEL

PERFORATED _]
METAL PAN

channel clip, 1

channel glazing A method of window glazing
which uses removable, surface-mounted, U-shaped
metal stops or beads to fix the glass in place.

channeling A series of grooves in an architec-
tural member, such as a column.

channeling

channel iron, channel bar A rolled iron or
steel bar whose U-shaped cross section is formed

by a broad central section, called a "web," with a
flange on either side.

channel mopping See strip mopping.

channel pipe A drain pipe having a half or three-
quarter circular cross section; open along the top.

channel runner A heavy horizontal member
in suspended ceiling construction.

channel section Same as channel, 1 .

chantlate A piece of wood fastened to the
rafters at the eaves and projecting beyond the
wall, so as to prevent rainwater from trickling
down the face of the wall.

chantry A chapel within a church, endowed
for religious services for the soul of the donor or
others he may designate.

chantry chamber The room or rooms used by
the priest(s) attached to a chantry.

chapel l.A small area within a larger church,
containing an altar and intended primarily for
private prayer. 2. A room or a building desig-
nated for religious purposes within the complex
of a school, college, hospital, or other institu-
tion. 3. A small secondary church in a parish.

•Ma

chapel, 1

chapel of ease A church built within the
bounds of a parish for the attendance of those
who cannot reach the parish church conveniently.

chapel royal The chapel of a royal castle or
palace.

chapiter Same as capital.

198

chase mortise

chaplet An astragal or bead molding, some-
times enriched with carved foliage.

chapter house A place for business meetings
of a religious or fraternal organization; occasion-
ally also contains living quarters for members of
such a group.

chaptrel A small capital of a vaulting shaft.

chaptrel

charcoal filter A filter for removing odors,
vapors, and dust particles from air, employing
activated charcoal as the filter element.

charette 1 . The intense effort to complete an
academic architectural problem within a speci-
fied time. 2. The time in which this work is done.

charge The quantity of refrigerant in a refriger-
ation system.

charging Feeding materials into a concrete or
mortar mixer, furnace, or other receptacle where
they will be further treated or processed.

charging chute An enclosed vertical chute
with doors through which waste material is
dropped down and fed into an incinerator.

charging door A door to an incinerator
through which waste is passed into the combus-
tion chamber.

Charleston house An 18th- or early- 19th-
century town house in Charleston, South
Carolina; usually Georgian or Greek Revival
style, two stories high, with the first story often
well above ground level. Such houses were of two
types. The first and more common type, called a
single house, was long and narrow, a single room
deep, built with its long side perpendicular to the
street; on the long side facing a garden was a two-
tiered colonnaded porch onto which all rooms
opened; the entrance was by a flight of stairs
leading from the street up to the porch. The sec-
ond type, called a double house, had a facade fac-
ing the street and was two rooms deep, boxlike in

shape, and had a portico with a classical two-
tiered porch in the middle of the facade.
charnel house A building or chamber for the
deposit of the bones of the dead.

Charonian steps, Charon's staircase In

the early Greek theater, a flight of steps from the
middle of the stage to the orchestra; used by
characters from the underworld.
Charpy test A single-blow impact test utilizing
a falling pendulum which breaks a specimen,
usually notched, supported at both ends.

Chartered Building Surveyor A building
surveyor who is a member of the Royal Institu-
tion of Chartered Surveyors.

chartered builder In Britain one who has been
admitted as a member or fellow of the Chartered
Institute of Building.

chartered engineer An individual who is a
full member of one of the chartered engineering
institutions.

Chartered Institute of Building In Britain,
an institution open to all professionals in the
field of building.

Chartered Institute of Building Services

A British organization members whose are con-
cerned with services within a building related
to the building environment, including: heating,
air-conditioning, lighting, acoustical, water sup-
ply services, drainage services, electrical supply,
gas supply, fire protection, and security protection.

charterhouse A Carthusian monastery.

chartophylacium A place for the safe keep-
ing of records and other valuable documents.

chartreuse A monastery of the Carthusian
monks, esp. in France.

chase 1 . A continuous recess built into a wall to
receive pipes, ducts, etc.; a wall chase. 2. A
groove cut in a masonry wall to receive a pipe,
conduit, etc. 3. To decorate metalwork by tool-
ing on the exterior surface.

chase bonding Joining old masonry work to
new by means of a bond having a continuous
vertical recess the full height of the wall.

chase mortise, pulley mortise A stub
mortise which is larger than the tenon inserted
into it; one side of the mortise is sloped, per-
mitting the tenon to be inserted sideways; used
where exterior clearance is limited.

199

chase wedge

chase wedge A wedge-shaped tool with a han-
dle; used for bossing sheet lead.

chase tenon A tenon that can be inserted into
its chase mortise, either laterally or lengthwise.

chasovnya In early Russian architecture, a
chapel which is a detached structure.

chasse A container for a saint's relics.

chat A stony mineral material, occurring with
mineral ore; very similar to chert.

chateau 1 . A castle or imposing country resi-
dence of nobility in old France. 2. Now, any
French country estate.

chateau, 1

chateau d'eau At the termination of an aque-
duct, a reservoir architecturally embellished as a
public fountain.

Chateauesque style, Chateau style,
Chateauesque Revival An opulent archi-
tectural style patterned after the design of monu-
mental French chateaus of the 16th century;
popular in the late 19th century and beyond.
Buildings were usually characterized by a facade
having masonry walls; an attic story; a single bal-
cony or continuous balconies; prominent use of

Chateauesque style

vertical elements such as pilasters; wall dormers
with gables that might break the roof line; cross
gables; a belt course; an ornately hipped roof
either steeply pitched to a ridge and/or truncated
by a horizontal surface; cast-iron cresting on
the roof; through-the-cornice wall dormers; roof
dormers with pedimented parapets, pinnacles,
and spires; a cylindrical corner turret having a
conical roof; tall, decorative chimneys and orna-
mental chimney caps; windows, frequently in
pairs, divided by heavy stone mullions; oriels;
semicircular bay windows; exterior door set
arches; often a canopy was provided over the
entry door.
chatelet A castle of small scale.

chat-sawn finish In stone masonry cutting,
the moderately rough surface resulting from the
use of coarse chat (crushed chert) as the abrasive
agent carried by the gang saw blades.

chattel 1. Any article of property not consisting
of or affixed to land; movable property. 2. Same
as 1, above, plus any interest in land that is less
than a freehold. When this nomenclature is
used, the term chattel personal is employed to des-
ignate movables such as goods and money, and
chattel real to designate less-than-freehold inter-
ests in real property, such as leasehold interests
for a term of years.

chattel mortgage A security interest in a
chattel as collateral for the payment of a loan.

chatter marks Intermittent transverse marks
on a material due to vibration during rolling,
extrusion, cutting, or drawing.

chattra Atop a stupa, a stone umbrella symbol-
izing dignity; composed of a stone horizontally
oriented disk on a vertical pole.

chattravali Similar to a chattra, but having
three horizontally oriented stone disks; a triple
umbrella; see illustration for stupa.

chauntry Same as chantry.

cheapener An extender in paint; not necessar-
ily cheap; more expensive extenders may be used
to provide such properties as hardness, wearabil-
ity, gloss control, and improved brushability.

check 1. A small crack running parallel to the
grain in wood and across the rings; usually
caused by shrinkage during drying; in veneers,
may improve the appearance. 2. A minute crack
in steel which has been cooled too abruptly.

200

check valve

check, 1

3. An attachment that limits movement, such as
a door check. 4. See checking.
check cracks See checking.

check dam A barrier in an erodible channel to
control the flow of water.

checked back Having a rabbet; receding.

checker, chequer One of the squares in a
check pattern, contrasted to its neighbors by
color or texture; often only two effects are alter-
nated, as in a chessboard. Also see diaper.

checkered plate l.A cast steel or iron plate
having square, flat projections suggestive of a
checkerboard. 2. A floor plate.

checkerwork In a wall or pavement, a pattern
formed by laying masonry units so as to produce
a checkerboard effect.

checkerwork

check fillet On a roof, a curb used to divert or
control the flow of rainwater.

checking, check cracks, map cracks,
shelling 1. Shallow cracks at closely spaced
but irregular intervals on the surface of mortar or
concrete. 2. Small cracks in a film of paint or
varnish which do not completely penetrate to
the substrate or the previous coat. The cracks are
in a pattern roughly similar to a checkerboard. 3.
In plastering, in a lime finish coat, fine spider-web
cracks or fissures; usually caused by insufficient
troweling or undergauging. 4. See check. 5.
Very small cracks in a flat glass surface, usually
along an edge.

checking floor hinge A door pivot, fixed
in the floor, which includes a mechanism for
controlling the speed of the door as it closes.

checking floor hinge

checking resistance The ability of a paint
coating, or the like, to resist slight breaks that do
not penetrate to the previously applied coating
or substrate.

check lock A small lock whose function is to
check the bolt of a larger lock that secures a door.

check nut Same as locknut, 2.

check rail In a double-hung window, a hori-
zontal meeting rail esp. one which overlaps the
other meeting rail.

checkroom A cloakroom, 3.

check stop A strip or molding used to hold a
sliding element in place, as at the bottom sash of
a double-hung window.

check strip A parting bead.

check throat A groove cut on the underside of
a windowsill or doorsill to prevent the passage of
drops of rainwater to the wall.

check valve, back-pressure valve, reflux
valve An automatic valve which permits liq-
uid to flow in only one direction. Also see non-
return valve.

check valve

201

cheek

cheek 1. A narrow upright face forming the
end or side of an architectural or structural
member, or one side of an opening. 2. A narrow
upright face forming the end or a side of an
architectural or structural member. 3. The
upright face of one side of an opening.

cheek boards In concrete formwork, the
boards on the sides of the form.

cheek cut, side cut An oblique angular cut at
the lower end of a jack rafter or the upper end of
any rafter so that it can fit tightly against a hip
rafter or valley rafter.

cheesiness The characteristic of a partially
dried paint film which results in tearing and
crumbling when pulled with the fingernail.

chemical bond A bond obtained as a result of
cohesion between layers of similar crystalline
materials, owing to the formation and the inter-
locking of crystals.

chemical brown stain See kiln brown stain.

chemical closet See chemical toilet.

chemical flux cutting An oxygen-cutting

process wherein the severing of metals is effected
by the use of a chemical flux to facilitate cutting.

chemical grout A fluid used in the chemical

stabilization of soils.

chemically foamed plastic A cellular plas-
tic whose structure is produced by gases gener-
ated from the chemical interaction of its
constituents, as a foamed plastic.

chemically prestressed cement An expan-
sive cement which contains a higher percent-
age of expansive component than shrinkage-
compensating cement.

chemically prestressed concrete A con-
crete made with expansive cement and rein-
forcement under conditions such that tensile
stress is induced in the reinforcement as a result
of the expansion of the cement, so as to produce
prestressed concrete.

chemical plaster Same as patent plaster, 2.

chemical-resistant paint A specially formu-
lated paint finish which utilizes binders and
pigments that are unaffected by chemicals.

chemical stabilization The inj ection of chem-
icals into a soil to improve its strength and
decrease its permeability.

chemical staining Treatment of wood with
chemicals to obtain color change and enhance
grain contrast.

chemical toilet, Brit, chemical closet A

toilet without conventional water and drain
connections; contains a fluid, usually with a
disinfectant and deodorant, which neutralizes
waste matter chemically.

chemin-de-ronae

chemin-de-ronde A continuous gangway
behind a rampart, providing a means of commu-
nication along a fortified wall.

chemise A wall (often concentric with the
keep) built around a medieval fortification of a
bastion or keep.

cheneau 1. A gutter at the eaves of a building,
esp. one that is ornamented. 2. An ornamented
crest, 2 or cornice.

chequer See checker.

cherry An even-textured, moderately high-
density wood of the eastern US, rich red-brown
in color; takes a high luster; used for cabinet-
work and paneling.

cherry mahogany See makore.

cherry picker A machine for lifting men or
materials on a platform at the end of an extend-
able boom; usually mounted on a carrier with
wheels to provide mobility.

chert A very fine-grained dense rock consist-
ing of chalcedony or opal, often with some
quartz, and sometimes with calcite, iron oxide,
organic matter, or other impurities; has a homo-
geneous texture and white, gray, or black color;
some of its constituents may react with cement
alkalies and therefore may be undesirable as
concrete aggregate for exposed concrete in
northern climates.

chestnut A light, coarse-grained, medium-hard
timber; used for ornamental work and trim.

202

chimney

cheval-de-frise, pi. chevaux-de-frise Sharply
pointed nails or spikes set into the top of a barrier.

chevet The apse, ambulatory, and radiating
chapels of a church.

chevron l.A V-shaped stripe pointing up or
down, used singly or in groups in heraldry and on
uniforms; hence, any ornament so shaped. 2. A
molding showing a zigzag sequence of these
ornaments in Romanesque architecture or deriv-
atives; a dancette or zigzag molding.

chevron, 2

chevron pattern A V-shaped zigzag pattern
used as an ornament in brickwork bond.

chevron slat A V-shaped slat used in an open-
ing to provide privacy and ventilation.

Chicago Commercial style See Commer-
cial style.

Chicago cottage A small, narrow, inexpen-
sive, quickly built cottage set on a brick founda-
tion with its lower story partially below ground
level; characterized by balloon framing, clap-
board exterior walls, an exterior stair between
the street and a second-story entrance, an attic
above the second story; developed for specula-
tion in Chicago in the mid- to late 1800s.

Chicago School A group of highly influential
architects, including Adler and Sullivan, Burn-
ham and Root, William LeBaron Jenney, and
their followers in Chicago in the latter part of
the 19th century. The School's central philoso-
phy was that architectural design should be of its
time rather than based on the past. This group
initially applied its philosophy to both skyscrap-
ers and homes, but its greatest and most lasting
influence was in the design of skyscrapers, and
its greatest achievements were in structural
design. Also see Prairie School.

Chicago window A large plate-glass window
in a commercial building with an operable win-
dow on each side to provide ventilation; because
of its large size, it provided greater natural illumi-
nation than earlier windows. Widely used in high
buildings in Chicago in the late 19th century.

chicken house See poultry house.
chicken ladder Same as crawling board.

chicken wire A light-weight, galvanized wire
netting having a hexagonal mesh.

chien A standard unit of floor space or bay of a
Chinese dwelling.

chien»assis A small unglazed dormer window
used to provide light and ventilation in an attic
below a sloping roof; especially used in the mid-
dle ages.

chigi On the roof of a Shinto temple, a decora-
tive pair of curved timbers that extend above
and beyond the roof ridge, crossing at the ridge.

chilled-water refrigeration system A
refrigeration system employing water as the
circulating liquid.

chiller Mechanical equipment used to circulate
chilled water throughout a building; consists of a
compressor, condenser, and evaporator.

chilling On a painted or varnished surface, a
clouding of the surface or a reduction of luster as
a result of the movement of cold air over the dry-
ing surface.

CHIM On drawings, abbr. for chimney.

chimney An incombustible vertical structure
containing one or more flues to provide draft
for fireplaces, and to carry off gaseous products
of combustion to the outside air from fire-
places, furnaces, or boilers. Also see clay-and-sticks

chimney

20]

chimney apron

chimney, double chimney, double-shouldered
chimney, end chimney, flush chimney, mud-
and-sticks chimney, outside chimney, pilastered
chimney, sloped-offset chimney, stepped-back
chimney, sticks-and-clay chimney, diagonal chim-
ney stacks.

chimney apron A nonferrous metal flash-
ing built into the chimney masonry and roof-
ing at the penetration of the roof by the
chimney.

chimney arch The arch over the opening of a
fireplace, supporting the breast.

chimney back See fireback.

chimney bar, turning bar A wrought-iron
or steel lintel which is supported by the sidewalls
and carries the masonry above the fireplace
opening. If curved, it is known as an arch bar.

chimney block A solid concrete masonry unit
with curved faces, intended for use with other
similar units in laying up a round flue.

chimney board Same as fireboard.

chimney bond A stretcher bond used in inter-
nal construction in chimneys.

chimney breast, chimney piece A projec-
tion into a room of fireplace walls forming the
front portion of the chimney stack.

chimney can A chimney pot.

chimney cap, bonnet l.An abacus or cor-
nice forming a crowning termination of a chim-
ney. 2. A rotary device, moved by the wind,
which facilitates the escape of smoke by turning
the exit aperture away from the wind, prevent-
ing the entry of rain or snow and improving the
draft. 3. A chimney hood.

F I

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<ll

IDE

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— t ■ — —

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ill

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~ir

chimney cap with corbel, 1

chimney cheek The sides of a fireplace open-
ing which generally support the mantelpiece.

chimney connector A pipe or metal breech-
ing which connects and makes the transition
from furnaces and boilers to the flue of a chimney.

chimney corner, inglenook, roofed ingle
An area adjacent to the hearth, usually provided
with seating.

chimney cowl A revolving metal ventilator
over a flue which induces updrafts and prevents
downdrafts; a chimney cap, 2.

chimney crane A pivoted arm of cast iron
attached to the rear wall of the fireplace upon
which to hang pots for cooking.

chimney cap, 1

chimney crane (1796)

chimney cricket A small false roof built over
the main roof behind a chimney; used to provide
protection against water leakage where the
chimney penetrates the roof.

chimney crook, chimney hook In a fire-
place, a cast-iron bar, hooked at the lower end
and adjustable in length, upon which to suspend
pots from a crane or other support.

chimney effect, flue effect, stack effect
The tendency of air or gas in a shaft or other ver-
tical passage to rise when heated, owing to its

204

chimney tun

lower density compared with that of the sur-
rounding air or gas.
chimney flue See flue.

chimney foundation A very large substruc-
ture, in a cellar, that supported the load of a huge
fireplace and massive centrally located chimney
and transmitted this load to the earth or rock
below; such a foundation was necessarily immense
because of the heavy load of the fireplace above
it. Usually rectangular in shape and constructed
of brick, stone, fieldstone, stone rubble, or some
combination thereof.

chimney girt In a timber-framed house, a
structural framing timber that served as a main
horizontal support between chimney posts.

chimney gutter A preformed nonferrous
metal flashing, used for waterproofing where a
chimney pierces a pitched roof.

chimneyhead The top of a chimney.

chimney hood A covering which protects a
chimney opening.

chimney hood

chimney hook A device for hanging pots for
cooking; see chimney crane.

chimney jamb One of the two vertical sides of
a fireplace opening.

chimney lining See flue lining.

chimney lug Same as randle bar.

chimney mantel See mantelpiece, chimney
piece.

chimney pent A small structure, set flush
between two exterior brick chimneys located on
an end wall of a house; covered by a small nar-
row sloping roof at the level of the ground floor
ceiling, buttressing the chimneys.

chimney piece An ornament over and around
a fireplace framing the mantel or the casing of
the chimney breast.

chimney post In a timber-framed house, one
of the wood posts providing the main vertical

chimney pent

structural supports at the front and rear sides of a
chimney.
chimney pot, chimney can A cylindrical
pipe of brick, terra-cotta, or metal placed atop a
chimney to extend and thereby increase the draft.

chimney pot

chimney shaft That part of a chimney which
is carried above the roof of a building of which it
forms a part.

chimney stack 1. A group of chimneys carried
up together. 2. A very tall chimney, usually round
in cross section, attached to factories, mills, etc.

chimney stalk Same as chimney stack.

chimney terminal Same as chimney cap.

chimney throat, chimney waist The nar-
rowest portion of a chimney flue, between the
"gathering" (or upward contraction above
the fireplace) and the flue proper; often where
the damper is located.

chimney tile Same as fireplace tile; see also
Dutch tile.

chimney top That part of a chimney that
extends above the roof or crowns the chimney
stack.

chimney tun A chimney stack.

205

chimney waist

chimney waist Same as chimney throat.

chimney wing Same as chimney cheek.

China grass cloth Same as grass cloth.

china sanitary ware Glazed, vitrified, sani-
tary ware.

China white See silver white, 2.

China wood oil See tung oil.

chinbeak molding One consisting of a con-
vex followed by a concave profile, with or with-
out a fillet below or between, as an inverted
ogee, or an ovolo, fillet, and cove.

Chinese architecture A highly homogeneous
traditional architecture which repeated through-
out the centuries established types of simple,
rectangular, low-silhouetted buildings costructed
according to fixed canons of proportions and
construction methods. Stone and brick were used
for structures demanding strength and perma-
nence, such as fortifications, enclosure walls,
tombs, pagodas, and bridges. Otherwise buildings
were mostly constructed in a wooden framework
of columns and beams supported by a platform,
with nonbearing curtain or screen walls. The
most prominent feature of the Chinese house was
the tile-covered gabled roof, high-pitched and
upward-curving with widely overhanging eaves
resting on multiple brackets. Separate roofs over
porches surrounding the main buildings or, in the
case of pagodas, articulating each floor created a
distinctive rhythmical, horizontal effect.

Chinese blue l.A pigment in the iron blue
family. 2. One type of Prussian blue.

Chinese bond Same as rat-trap bond.

Chinese Chippendale Descriptive of lattice
patterns suggestive of Chinese motifs designed
by Thomas Chippendale (1718-1779), England's
most widely known furniture maker of his time.
Such designs were a combination of horizontal,
vertical, and diagonal lines, forming geometric
patterns, usually within a rectangular frame;
especially used in railing systems.

Chinese fret A lattice pattern of Chinese
motif described under Chinese Chippendale.

Chinese lacquer, Japanese lacquer, lac-
quer A hard-wearing varnish drawn from nat-
ural sources, as from the Japanese varnish tree.

Chinese lattice A combination of horizontal,
vertical, and diagonal lines, slats, or bars, that form
a geometric pattern, as in Chinese Chippendale.

Chinese white A paint using zinc oxide as the
principal pigment.

chink In a wall, a crack or fissure of greater
length than breadth.

chinking The material used to fill chinks (i.e.,
long cracks, openings, or fissures), especially
between logs that form the exterior walls of log
cabin construction. Where the cracks are small,
the filling material is often mud or plaster; where
the cracks are large, the filling may include
wood chips, pebbles, straw, or small sticks.

chinking in a log wa

chinking board A board used to cover chink-
ing in an exterior wall.

chinoiserie A Western European and English
architectural and decorative fashion employing
Chinese ornamentation and structural elements,
particularly in 18th cent. Rococo design.

chip A broken fragment of marble or other min-
eral aggregate, screened to a specified size.

chip ax A small ax for chipping timber or stone
into shape.

chipboard See particleboard.

chip carving Hand-decorating a wood surface
by slicing away chips, forming incised geometric
patterns.

chip cracks, eggshelling Same as checking
except that the edges of the cracks are raised or
pulled away from the plaster base, resulting in
the loss of bond.

chip concrete Concrete which uses broken
stones as an aggregate, 1; provides greater bend-
ing and splitting tensile strength than concrete

206

chomper

which has gravel as an aggregate because of the
rougher surfaces of the broken stones.

chipped glass See chunk glass.

chipped grain A wood surface from which
small bits have been ripped as a result of defec-
tive planing or machine work.

chipper See paving breaker.

chipper chain saw A chain saw whose cut-
ting teeth are shaped so as to permit curved cuts.

chipping Treatment of a hardened concrete
surface by chiseling.

chipping resistance Of a paint coating (or
the like), the ability of one or more coats to
resist the removal of any portion of its surface as
a result of impacts.

chisel A hand tool with a cutting edge on one
end of a metal blade (usually steel); used in
dressing, shaping, or working wood, stone,
metal, etc.; usually driven with a hammer or
mallet. Also see cold chisel and wood chisel.

N'-Aj.;

Z2I

chisel

chisel bar A heavy, steel hand bar with a chisel
edge on one end.

chisel chain saw A chain saw whose cutting
teeth are shaped so that it can only make
straight cuts.

chisel knife A knife with a square edge, usually
l l Am. (3.8 cm) or less in width, used to scrape off
paint or wallpaper in areas where a wider-edged
stripping knife would not be suitable.

chisel pattern A pattern of shingles or tiles on
a roof in which the bottom corners of the shin-
gles or tiles are clipped at an angle.

chlorinated paraffin wax A viscous liquid
or solid used as a plasticizer or in flame -retardant
paints.

chlorinated polyethylene A synthetic
material that is widely used as a roofing material.

chlorinated polyvinyl chloride (PVC) A
plastic, widely used for piping in both hot- and
cold-water systems and in drainage systems —
especially where corrosion may be a problem.

chlorinated rubber A white powder containing
67% rubber by weight, produced by the reaction of

chlorine and rubber; used in plastics, adhesives,
and corrosion- and acid-resistant paints.

chock A wedge or block used to prevent an
object from moving.

choir That part of a church, between the sanc-
tuary and the nave, usually occupied by a group
of singers.

choir aisle An aisle parallel to and adjoining

the choir.
choir loft A balcony choir area.
choir rail A railing separating the choir from

the nave or the crossing.
choir screen, choir enclosure A screen

wall, railing, or partition of any type dividing the

choir from the nave, aisles, and crossing.

choir screen

choir stall A seat with arms and a high back,
often covered with a canopy, for clergy and singers.

choir wall A wall between piers and under an
arcade screening the choir from the aisles.

choltry Same as choultry.

chomper Same as split-face machine.

207

choneion

choneion In the Greek Orthodox church, a

piscina.
chopping block See butcher block.

choragic monument In ancient Greece, a
commemorative structure, erected by the suc-
cessful leader in the competitive choral dances
in a Dionysiac festival, upon which was dis-
played the bronze tripod received as a prize; such
monuments sometimes were further ornamented
by renowned artists.

choragium In ancient Greece and Rome, a large
space behind a theater stage where the chorus
rehearsed and where stage properties were kept.

choraula Rehearsal room in a church for a choir.

chord 1. A principal member of a truss which
extends from one end to the other, primarily to
resist bending; usually one of a pair of such mem-
bers. 2. The straight line between two points on
a curve. 3. The span of an arch.

UPPER CHORD

chrismon Christ symbol composed of the first
two letters of the Greek word for Christ, chi and
rho; a "Christogram."

Christian door In Colonial New England, the
paneled front door of a house in which the stiles
and rails of the door form a pattern suggestive of a
cross, the two lower stiles and rails form a pattern
vaguely suggestive of an open book, representing
the Bible. Also called a cross-and-bible door.

chord, 1

Christian door

chord, 3

chord modulus See modulus of elasticity.

choultry 1. A caravansary. 2. In India, a large

village hall or place of assembly.
chrismatory A niche close to a church font

which holds the consecrated oil for baptism.

Christogram See chrismon.

chromate To coat a metal surface with a rust-
inhibiting primer of lead or zinc chromate.

chromaticity The color quality of light defin-
able by its dominant (or complementary) wave-
length and its purity, taken together.

chrome green l.A green pigment made by
blending lead chromate yellow and iron blue
pigments. 2. Chromium oxide.

chrome steel A very hard wear-resistant steel
having a high elastic limit; usually contains 2%
chromium and from 0.8 to 2% carbon.

chrome yellow, Leipzig yellow A family
of inorganic yellow pigments, principally lead
chromate, but blended with lead sulfate or other
lead salts to produce a range of yellow-to-orange
pigments.

chromium A hard, brittle metal resistant to
corrosion, workable when annealed, gray-white
in color; used in alloys, esp. steel, and in plating.

208

cincture

chromium oxide A durable green pigment
having good alkali resistance; rather expensive
and sparingly used.

chromium plating A plating with chromium
used to provide a protective finish which is
extremely resistant to corrosion and a surface of
extreme hardness; used for decorative purposes
because of the smooth surface and ability to take
a high polish.

chromium steel Same as chrome steel.

chronic-disease hospital An institution which
provides facilities and services primarily for chron-
ically ill patients who require long-temr care.

chryselephantine Made of gold and ivory;
descriptive of statues of divinities, like Zeus at
Olympia, with ivory for the flesh and gold for
the drapery, on a wooden armature.

CHU Abbr. for centigrade heat unit.

chuck A device with adjustable jaws used for
centering and holding a cutting bit, drill bit,
etc.

ikiafli,

REMOVABLE
CHUCK KEY

chuck

chuff brick See salmon brick.

chunk glass A piece of glass of unusual thick-
ness; many times thicker than ordinary glass.

church An edifice or place of assemblage specif-
ically set apart for Christian worship.

church house A building used for the social
and secular activities of a parish.

church stile Old English for pulpit.

churn drill A drill whose cutting action is
achieved by raising and dropping a chisel bit.

churn molding Same as zigzag molding.

Churrigueresque style A Spanish decora-
tive style, often used in the late 17th century
and the first half of the 18th century, character-
ized by elaborate and lavish Baroque ornamen-
tation and detailing; named after the Spanish

upper facade of a chapel in the Churrigueresque style

architect Jose Churriguera (1655-1725); also
see Mission architecture, Plateresque architec-
ture, Spanish Colonial architecture.

chute An open-top trough through which bulk
materials are conveyed and lowered by gravity.

chymol Same as gemel.

CI On drawings, abbr. for cast iron.

ciborium A baldachin.

CIB Abb. for "International Council for Build-
ing Research Studies and Documentation," Rot-
terdam, the Netherlands.

CIBS Abbr. for "Chartered Institution of Build-
ing Services."

CIE Abbr. for "Commission Internationale
de l'Eclairage" (International Commission on
Illumination).

cif Abbr. for "cost, insurance, and freight."

cilery The ornamental carving, such as foliage,
around the capital of a column.

cill British term for sill.

cillery Same as cilery.

cill-wall A low, narrow, masonry wall that sup-
ports a timber-framed structure; keeps the lowest
beam (i.e., the cill-beam) dry, and thus prevents
it from rotting.

cima See cyma.

cimbia A band or fillet around the shaft of a
column.

cimborio A lantern or cupola above or nearly

above the high altar in Spanish architecture.
cimeliarch The treasury of a church for storing

valuables such as ceremonial garb and holy

objects.
cinch See lead pipe cinch.
cincture, girdle A ring of moldings around the

top or bottom of the shaft of a column, separating

209

cinder block

the shaft from the capital or base; a fillet around
a post. Also see necking.

cinder block, Brit, clinker block A light-
weight masonry unit made of cinder concrete;
widely used for interior partitions.

cinder concrete A lightweight concrete made
with cinders as the coarse aggregate.

cinders 1. Blast-furnace slag or similar material
from volcanoes. 2. Ashes, esp. from soft coal.

cinerarium A depository for urns containing
the ashes of the dead.

Cinquecento architecture Renaissance ar-
chitecture of the 16th cent, in Italy.

cinquefoil A five-lobed pattern divided by
cusps; also see foil.

cinquefoil

cinquefoil arch A cusped arch having five
foliations worked on the intrados.

CIOB Abbr. for "Chartered Institute of Building."

CIP Abbr. for "cast-iron pipe."

cippus A small pillar for commemorative
inscriptions, boundary markers, gravestones, etc.

CIR 1. On drawings, abbr. for "circle" or "circu-
lar." 2. On drawings, abbr. for "circuit."

CIR BKR On drawings, abbr. for circuit breaker.

CIRC On drawings, abbr. for "circumference."

circle end A starting step having the shape of a
half circle.

cinquefoil arch

circle-on»circle face See circular-circular face.

circle trowel A trowel having a concave or
convex blade; used in plastering curved sur-
faces.

circline lamp A fluorescent lamp tube bent in
the form of a circle; the entire lamp forms a
toroid.

circuit 1. A continuous electrical path, or a sys-
tem of conductors, through which an electric
current is intended to flow. 2. An assembly of
pipes and fittings, forming part of a hot-water
system, through which water circulates.

circuit breaker An electric device for opening
and closing a circuit, designed to open the cir-
cuit automatically upon flow of a predetermined
value of abnormally high current; may be repeat-
edly reclosed and reused as an automatic over-
current protection device without replacement
of any components.

circuit controller Any type of device used to
close and/or open an electrical circuit.

circuit main See main, 1.

circuit vent In plumbing, a branch vent which
serves two or more traps and extends from in front
of the last fixture connection of a horizontal
branch to the vent stack.

circular arch An arch whose intrados takes
the form of a segment of a circle.

circular barn A barn having a circular plan;
requires less building material than a rectangular
barn enclosing the same volume, but usually
costs somewhat more to construct. Also called a
cylindrical barn or a round barn.

210

circular window

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circular arch

circular barn

circular-circular face, circle-on-circle face

In stonework, carpentry, and joinery: a face
worked to convex spherical shape, presenting a
curved outline in both plan and elevation.

circular-circular sunk face, circle-on-circle
sunk face Same as circular-circular face but
presenting a concave outline, in both plan and
section.

circular cutting and waste A measure of the
excess tiling, flooring, roofing material, etc., that

must be discarded when a curved floor or roof

is laid.
circular face In stonework, a face worked to

convex circular shape.
circular mil-foot A unit electric conductor

having a cross-sectional area of 1 circular mil

and a length of 1 ft.
circular mill The area of a circle having a

diameter of 1 mil ( M.oooin.); used in specifying

wire size; equals an area of 0.0005 1 sq mm.
circular miter The miter formed by the inter-
section of a curved and a straight piece.
circular plane Same as compass plane.
circular saw A power-operated saw in the form

of a circular steel blade with teeth along the

perimeter. Also see table saw.

circular saw

circular spike A type of metal timber connec-
tor having a series of sharp teeth in a circle; the
teeth dig into the wood as a bolt is tightened,
thereby preventing lateral motion.

circular spike

circular stair Same as spiral stair; a stair having

a cylindrical staircase.
circular sunk face In stonework, a face

worked to concave circular shape; the opposite

of circular face.
circular window A large window having the

shape of a full circle; often has decorative elements

within the circle disposed in a radial manner.

211

circular work

circular work See compass work.
circulating head, circulating pressure A

measure of the pressure available in a hot-water
supply system for circulating water around the
convection circuit.

circulating water system A system in which
the same water circulates around a closed loop;
sometimes a small amount must be added to
make up for losses.

circulation l.The traffic pattern through an
area or building. 2. In a building, a scheme pro-
viding for a smooth, economical, and functional
flow of traffic. 3. A means of travel through a
building, such as doors, corridors, stairs, and ele-
vators. 4. The continuous flow of a liquid or gas
within a closed circuit.

circulation area See primary circulation area.

circulation path Same as circulation, 3.

circulation pipe A pipe forming part of the pri-
mary or secondary circuit of a hot-water system.

circulation-type hot-water supply system
A supply system which circulates water through
a storage tank and one or more gas-fired heaters
by means of a pump; circulation improves the
transfer of heat and the temperature distribution
within the system.

circumvallate To surround an area with a wall
or ramparts.

circumvolution One of the turns in the spiral
of the volute of an Ionic capital.

circus, hippodrome In ancient Rome, a roof-
less enclosure for chariot or horse racing and for
gladiatorial shows; usually a long oblong with
one rounded end and a barrier down the center;
seats for the spectators usually on both sides and
around one end.

which the undercoat may be seen; a mild form
of crawling, 2. 2. A process for preparing a
wood surface for graining by wetting with a
sponge.

cist Same as cistvaen.

cistern An artificial reservoir or tank for stor-
ing water at atmospheric pressure (such as rain-
water collected from a roof) for use when
required.

cistern head Same as leader head.

cistvaen, kistvaen A Celtic sepulchral cham-
ber of flat stones set together like a box, and cov-
ered by a tumulus.

CIRIA Abbr. for "Construction Industry Re-
search and Information Association in Britain."

cissing, sissing 1 . A slight shrinkage of a glossy
paint coat resulting in small cracks through

citadel A fortress or castle in or near a city,
intended to keep the inhabitants in subjuga-
tion, or, in case of a siege, to supply a final
refuge.

city plan A large-scale, comprehensive map of
a city delineating streets, important buildings,
and other urban features compatible with the
scale of the map.

city planning, town planning, urban plan-
ning Planning a future community, or the
guidance and shaping of the expansion of a
present community, in an organized manner and
with an organized layout, taking into account
such considerations as convenience for its
inhabitants, environmental conditions, social
requirements, recreational facilities, esthetic
design, and economic feasibility; includes a
study of present requirements and conditions, as
well as projections for the future; such planning
usually includes proposals for its implementa-
tion. See community planning.

civery See severy.

civic center An area of a city where municipal
buildings are grouped; esp. includes the city hall,
court house(s), public library, and other public
buildings such as a municipal auditorium, art
gallery, etc.

212

clamshell

civic crown, civic wreath In ancient Rome,
an honorary ornament, consisting of a garland
of oak leaves, on a monument to one who had
saved the life of a Roman citizen in battle.

civil engineer An engineer trained in the
design of static structures such as buildings, roads,
tunnels, and bridges and the control of water and
its contaminants.

City Beautiful movement A movement in
the US, principally from about 1890 to the 1920s,
which advocated the beautification of cities.

CKT On drawings, abbr. for "circuit."

CKT BKR On drawings, abbr. for circuit breaker.

CL Abbr. for center line.

C'labeled door A door carrying a certification
from the Underwriters' Laboratories, Inc. that it
meets the requirements for a class-C door.

clachan A small village or hamlet in Scotland
or Ireland.

clack valve A type of check valve in which
the controlling element is hinged on one edge,
opening for flow in one direction and closing
when the flow is reversed.

cladding rail Same as girt.

clairecolle See clearcole.

clairvoyee, claire-voie An ironwork screen,

openwork fence, gate, or grille through which a

vista can be enjoyed.
clam The bucket of a clamshell.
clamp A wood and/or metal device designed to

hold components firmly, esp. during gluing,

machining, soldering, welding, etc.

clamp

clamp brick A stock brick which has been

held in a clamp while being burned in a kiln.
clamping plate A metal connector which is
bolted to a joint of a wooden frame to strengthen
it; a type of timber connector.

clack vat

clad Said of a surface that is surface sheathed.

clad alloy An alloy having metallurgically
bonded surface coating; applied as corrosion
protection, for surface appearance, for use in
brazing, etc.

clad brazing sheet A metal sheet which is clad,
on one or both sides, with a brazing filler metal.

cladding l.See siding. 2. A metal coating
which is bonded to another metal; see clad alloy.
3. In welding, the deposition of filler metal on a
metal surface to obtain desired properties or
dimensions; also called surfacing. 4. A nonstruc-
tural material (or the surface formed by such a
material) used as the exterior covering for the
carcass or framework of a building. 5. The surface
on which shingles, tiles, or clapboards are fas-
tened. Also see siding and veneer.

clamping plate

clamping screw See screw clamp.

clamping time The period of time a glued
joint must be tightly held during curing.

clamp nail A specialized fastener used to pull
and to hold mitered joints together.

clamshell l.A wood molding, the profile of
which resembles that of a clamshell. 2. A bucket
used on a crane or derrick for handling granular

clamshell, 1

213

clapboard

clamshell, 2

materials. Its jaw-like halves close and open by
cable or hydraulic action.

clapboard, bevel siding, lap siding A

wood siding commonly used as an exterior cov-
ering on a building of frame construction;
applied horizontally and overlapped, with the
grain running lengthwise; thicker along the
lower edge than along the upper.

clapboard gauge, siding gauge A device
used to space clapboards so that they are applied
parallel to each other.

clapboard house A term occasionally used as
a synonym for Virginia house.

clapboard

clapper In fire sprinkler systems, a type of seal-
ing assembly.

clapper valve Same as clack valve.

clapping stile Same as lock stile.

clarification drawing A graphic interpreta-
tion of the drawings or other contract documents

issued by the architect as part of an addendum,
modification, change order, or field order.

Clarke beam A type of built-up wood beam
consisting of joists or planks which are bolted
together and then reinforced with wood pieces
nailed along both edges of the joint.

clasp nail Same as cut nail.

clasping buttress A buttress that wraps around
the corner of a building.

class As applied to concrete: a characterization
according to some quality (such as compressive
strength) or usage.

class A, B, C, D, E, F A classification applied
to fire doors, fire windows, roof coverings, inte-
rior finishes, places of assembly, etc., to indicate
gradations of fire safety. See fire-endurance, fire-
door rating.

class- A door A door having a 3-hr fire-
endurance rating, suitable for use as a closure in
a class-A opening.

class-B door A door having a 1- or lJ^-hr fire-
endurance rating, suitable for use as a closure in a
class-B opening, such as fire exits and passageways.

class-C door A door having a %-hr fire-
endurance rating, suitable for use as a closure in
a class-C opening.

class-D door A door having a l!/2-hr fire-
endurance rating, suitable for use as a closure in
a class-D opening in an exterior wall.

class-E door A door having a %-hr fire-
endurance rating, suitable for use as a closure in
a class-E opening in an exterior wall.

Classical architecture The architecture of
Hellenic Greece and Imperial Rome on which
the Italian Renaissance and subsequent styles
such as the Baroque and the Classic Revival based
their development. The Five Orders are a charac-
teristic feature. See illustrations under order.

Classical order See order.

Classical Revival style An architectural
style, used in many major public buildings from
about 1770 to 1830 and beyond; typified by sim-
plicity, dignity, monumentality, and purity of
design; based primarily on the use of Roman
forms of classical antiquity, although later exam-
ples exhibit some characteristics of the Greek
Revival style which followed. Sometimes called
Early Classical Revival, Jeffersonian Classicism,

214

clay content

Neoclassical Revival, or Roman Classicism.
Buildings in this style were usually rectangular in
plan, two rooms deep, gable-fronted, with the
long side of the house commonly facing the
street; they commonly exhibit many of the fol-
lowing attributes: a symmetrical form sometimes
similar to a classical temple; two stories high,
often with one- or two-story wings; walls of
brick, stucco, stone, or wood construction; typi-
cally, a two-story monumental portico, painted
white, with a triangular pediment, frequently
with a semicircular window set within its tympa-
num; a pedimented roof, usually supported by
four columns on square bases; an entablature
above the columns; a low hipped roof, occasion-
ally partially hidden by balustrades; usually five-
ranked; a paneled door beneath a semicircular or
elliptical fanlight. Classical Revival architecture
reemerged in popularity from about 1895 to
1940, with modifications, as described under
Neoclassical style.

classic box A Colonial revival house having a
hipped roof and a full-width front porch.

classicism In architecture, principles that empha-
size the correct use not only of Roman and Greek,
but also of Italian Renaissance models.

Classic Revival A term often used as a syn-
onym for the Classical Revival style.

classified excavation An excavation in
which there are separate prices for common
excavation and for rock excavation; compare
with unclassified excavation.

class P ballast See ballast.

classroom window A window which is twice
as wide as an ordinary window, usually having
two or more side-by-side hopper lights and a sin-
gle fixed light above them.

classroom wim

dow

clause In the AIA documents, a subdivision of
a subparagraph, identified by four numerals, e.g.,
3.3.10.1.

claustral, cloistral Pertaining to a cloister.

clavel, clavis A keystone of an arch.

clavis See clavel.

claw bar See pinch bar.

claw chisel A chisel with a serrated cutting
edge; used in cutting stone.

claw hammer A carpenter's hammer with a
flat striking face; the other end of the head is
curved, and divided into two claws for pulling
nails.

claw hatchet See shingling hatchet.
claw plate A timber connector which is round
in shape.

clathri A lattice of bars, as of cages for animals
or gratings for windows.

claw plate

clay A fine-grained, cohesive, natural earthy
material; plastic when sufficiently wet; rigid when
dried; vitrified when heated in a kiln to a suffi-
ciently high temperature; used in making brick, as
wall infilling, and as daub in wattle-and-daub.

clay-and-hair mortar A plastic mixture of
clay and water to which animal hair is added to
improve the mechanical strength of the result-
ing mortar after it has dried.

clay-and-sticks chimney A chimney con-
structed of clay or mud and sticks, and then
coated on the interior with clay, mud, or plaster
to provide some protection against setting the
chimney on fire; used in homes in many frontier
areas where bricks, stones, and lime mortar were
not available.

clay binder See binder soil.

clay brick A solid masonry unit made of clay,
usually formed into a rectangular unit while in
the plastic state and treated in a kiln at an ele-
vated temperature to harden it.

clay cable cover A fired-clay covering for
underground electric cables.

clay content Of a heterogeneous material such
as soil or a natural concrete aggregate, the per-
centage of clay by weight.

215

clay masonry unit

clay masonry unit A building unit, larger
than a brick, composed of burnt clay, shale, fire
clay, or some mixture thereof.

clay-mortar mix Masonry mortar which has
been plasticized by the addition of finely ground
clay.

clay pipe See vitrified-clay pipe.

clay puddle See puddle.

clay size That portion of fine-grained soil that
is finer than 0.002 millimeter.

clay spade An attachment for a pneumatic
paving breaker, with a wide, flat chisel-like
working blade that cuts through cohesive mate-
rial like clay.

clay tile 1. A roofing tile of hard, burnt clay. 2.
In flooring, a quarry tile.

cleading The boards lining the sides of an exca-
vation, pit, or shaft.

cleanability The property of a paint film which
permits easy removal of dirt, stains, and other
surface contamination.

clean agent In a fire suppression system, any

electrically nonconducting, volatile, or gaseous
extinguishant that does not leave a residue when
it evaporates.

clean aggregate Fine or coarse aggregate, free
of such material as clay, silt, or organic substances.

clean back In masonry, the visible end of a
stone laid as a bondstone.

cleaning eye A cleanout.

cleaning sash, cleaning ventilator The
movable part of a window which opens only for
cleaning the window; usually unlocked with a
special key or wrench.

cleanout l.A pipe fitting with a removable
plug which provides access for inspection or
cleaning of the pipe run. Also called an access
eye or cleaning eye. 2. An opening at the base of
a chimney, stack, or breeching for the removal of
dust, soot, etc. 3. An opening in concrete forms
for removing debris; closed before the concrete
is placed.

cleanout door l.An ashpit door. 2. A door
providing access to a soil pipe, the base of a col-
umn form, or the like. 3. A soot door.

clean power Electric power having a relative
absence of electrical noise and harmonics so that
its voltage waveform is essentially a sine wave.

CLEANOUT

OUTLET

CLEANOUT

cleanout, 1: above: for cleaning pipe run; below: for a
P-trap

clean room An assembly room for precision
products whose quality would be affected by
dust, lint, or airborne pathogens; usually has
smooth room surfaces to prevent dust collection;
air precipitators or filters keep dust, lint, etc., to
a specified minimum level.

clean stuff Same as clear lumber.

clean timber British term for clear lumber.

clear The net distance, free from interruption,
between any two surfaces or areas.

clearage Same as clearance.

clearance l.Open space between two ele-
ments of a building to aid in proper placement,
to compensate for minor inaccuracies in cutting,
or to allow unobstructed movement between
parts. 2. The space or distance allowed for
anchorage or erection processes or to accommo-
date dimensional variations in the building
structure. 3. See door clearance.

clear ceramic glaze Said of an inseparable
ceramic glaze that is firebonded and translucent
or tinted with a lustrous finish.

clearcole, clairecolle l.A primer consisting
of glue, water, and white lead or whiting. 2. A
clear coating used in application of gold leaf.

216

climbing crane

clear dimension The open space between two
components or members of a building.

clear floor space According to the Americans
with Disabilities Act, the minimum unobstructed
floor space needed to accommodate a wheelchair
and its occupant.

clear glaze A colorless or colored transparent
ceramic glaze. Also see ceramic color glaze.

clear height A vertical height providing an
unobstructed clearance, 1 .

clearing The cutting down of bushes and trees
and the digging and removal of their roots and
stumps.

clearing arm A branch provided on a drain to
facilitate the clearing of obstructions with a
drain rod.

clear lumber, clean timber, clears, clear
stuff, clear timber, free stuff Wood free
of knots and other defects.

clear span The distance between the two
inside faces of the supports of a span.

clearstory Same as clerestory window.

cleat A small block or strip of wood nailed on a
member or on a surface; used to support a brace
or to hold a member or object in place tem-
porarily.

cleat 'wiring Electric wiring on cleats or insu-
lated supports which are mounted on a wall or
other surface, leaving the wiring exposed; con-
duits or raceways are not used.

cleat

wiring

cleavage l.In rocks, a tendency to split along
parallel, generally closely spaced surfaces as, for
example, in slate. 2. In some stone industries,
the splitting along the depositional layering. 3.
The rupturing of adhesive bonds between rigid
materials; a prying action. 4. A tendency in
some woods to split along closely spaced parallel
planes, as in shingles.

cleavage plane In a crystalline material, such
as certain types of rocks, a plane along which
splitting takes place most easily.

cleave board Same as rived board.

cleft finish Said of a stone that has good cleav-
age, 2 along parallel planes; for example, slate.

cleft timber Timber which has been split along
the grain to approximate dimensions.

cleithral Same as clithral.

clench See clinch.

clench bolt See clinch bolt.

clenching, clench nailing The hammering
over of the point of a nail against a wood face to
secure its adhesion under rough usage.

clench nail See clinch nail.

clerestory, clerestory window 1. An upper
zone of wall pierced with windows that admit
light to the center of a lofty room. 2. A window
so placed. (See illustration p . 218.)

clerestory, 2 A

clerk of the 'works The owner's site represen-
tative or owner's inspector at a construction site.

clevis An iron (or a link in a chain) bent into
the form of a horseshoe, stirrup, or letter U, with
holes in the ends to receive a bolt or pin. (See
illustration p. 218.)

CLG On drawings, abbr. for ceiling.

climbing crane A hoisting device used in the
erection of high-rise buildings; a vertical mast is
fastened to structural members of the building
framework and is moved up as the structure rises
during construction; a horizontal boom, equipped

217

climbing form

Support nut Lock nut

Gas supply
pipe

clerestory, 1

with a winch and hoist line, is swung from the top
of the vertical mast.

climbing form A concrete form which is raised
vertically for succeeding lifts, 6 of concrete in a
given structure, usually supported on anchor bolts
or rods embedded in the top of the previous lift;
the form is moved only after an entire lift is placed

Hanger rod

clevis hanger

and partially hardened; not the same as a slip form,
which moves during the placement of concrete.

clinch, clench To secure or fasten a nail, sta-
ple, screw, etc., by hammering the protruding
point so that it is bent over.

clinch bolt, clench bolt A bolt with one end
designed to be bent over, to prevent withdrawal.

clinching See clenching.

clinch joint Same as lap joint, 2 secured with
clinch nails.

clinch nail, clench nail Any nail designed
for clinching after driving.

clinic 1 . A facility, independent or part of a hos-
pital, in which ambulatory patients receive diag-
nostic and therapeutic medical and surgical care.
2. Single-focus or general-purpose units of the
entire facility, such as the cardiac clinic or the
pediatric clinic.

clink 1 . A short pointed steel bar; used, by strik-
ing with a sledgehammer, to break up pavement
or road surfaces. 2. One of many small cracks in
steel due to differential expansion in heating. 3.
A sealed edge between adjacent sheets of flexi-
ble-metal roofing material.

clinker l.A partially fused product of a kiln,
which is ground for use in cement; also called
cement clinker. 2. A vitrified or partially vitri-
fied residue of coal which has been burnt in a
furnace; used as an aggregate in cinder block. 3.
A clinker brick.

clinker block British term for cinder block.

clinker brick A very hard-burnt brick whose
shape is distorted, owing to nearly complete vit-
rification; used for paving.

clinometer An instrument for measuring verti-
cal angles.

218

close-contact glue

clip l.A portion of a brick cut to length. 2. A
special fastener made of light-gauge sheet metal
or wire for the attachment of gypsum lath to
channel or steel studs. 3. A small device, usually
of metal, for holding larger parts in place, either
by friction or by mechanical action, as a spring
device of metal used to hold glass in a window.

clip angle, lug angle A short angle iron that
takes a portion of the stress of any member.

clip bond A bond formed by clipping of the
inside corners of facing brick laid as stretchers so
as to form notches for the insertion of diagonal
headers.

clip bond

clip course A course of bricks that rests on a
clip joint.

clipeus An ornamental disk of marble or other
material, in the shape of a shield; often sculp-
tured in relief, hung in the intercolumniations of
the atria of ancient Roman dwellings.

clip joint A mortar joint which is thicker than
usual; used to bring a masonry course to a
required height.

clipped eaves Eaves that do not overhang
the face of a wall by more than the width of the
gutter.

clipped gable See jerkinhead.

clipped header, false header A half-brick
placed to look like a header for purposes of estab-
lishing a brickwork pattern, as in Flemish bond.

clipped lintel A lintel which is intermittently
attached to a structural member; the structural
member assists the lintel in carrying the load.

clithral In early Greek architecture, having a
roof that forms a complete covering; said of cer-
tain temples, as distinguished from hypaethral.

CLKG On drawings, abbr. for caulking.

CLO On drawings, abbr. for closet.

cloaca An underground conduit for drainage; a
sewer, esp. in ancient Rome.

cloak rail On a closet wall, a board on which
hooks are attached for hanging clothes.

cloakroom 1 . A room for the deposit or check-
ing of outer clothing. 2. A small lounge outside a

legislative chamber where coats may be hung. 3.
A room for checking packages or baggage, as in a
theater, railway station, or airport. 4. (Brit.) A
washroom and toilet.

clocher Same as belfry, 1.

clochan A type of primitive building peculiar
to Ireland, usually having a beehive form, con-
structed of the masonry usually neither dressed
nor cemented; a single stone covers the apex.

clocha

houses in County Kerry

cloisonne A surface decoration in which differ-
ently colored enamels or glazes are separated by
fillets applied to the design outline. For porce-
lain enamel, the fillets are wire secured to the
metal body; for tile and pottery, the fillets are
made of ceramic paste, squeezed through a
small-diameter orifice.

cloister A covered walk surrounding a court,
usually linking a church to other buildings of a
monastery.

cloistered arch Same as coved vault.

cloistered vault A coved vault.

cloister garth The courtyard within a cloister.
cloistral See claustral.

clone One of a series of plants that is repro-
duced by cuttings or other vegetative methods
for several generations.

close 1. An enclosed space around or at the side
of a building; esp. the neighborhood of a cathe-
dral. 2. A narrow lane leading from a street.

closed bidding Same as closed competitive
selection.

close-boarded, close- sheeted 1. Covered with
square-edge boards that are laid in close contact
with each other, as in roofing or siding. 2. Said of
fencing which is completely filled with vertical
boards having no spaces between them.

close-contact glue A glue which requires
very closely joined surfaces.

219

close couple

close couple See couple-close.

close-coupled tank and bowl A flush tank

which is separate from, but attached to, a toilet
bowl.

close-coupled tank and bowl

close»CUt Descriptive of a hip (or valley) on a
slate, shingle, or tile roof in which the pieces are
cut to meet exactly on the hip (or valley).

closed building system A building system in
which only its own subsystems, its own subassem-
blies, and its own components are interchangeable.

closed cell In a material such as foam rubber or
foam plastic, one of many air spaces (cells)
totally enclosed by its walls and hence not inter-
connecting with other cells.

closed-cell foam A cellular plastic in which
the cells do not interconnect.

closed-circuit grouting Injecting grout into
a hole (which intersects fissures or voids to be
filled) with sufficient volume and pressure so
that more grout is fed to the hole than is taken
up, the excess grout being returned to the pump-
ing plant for recirculation.

closed-circuit TV surveillance system A
system comprised of a TV camera and a monitor
connected by a coaxial cable; designed to pro-
vide visual surveillance; often an important
adjunct to a building security system.

closed-circuit telephone A telephone on a
circuit that provides telephonic communication
within a limited area, such as a single building; it
accepts no incoming calls from the outside nor
can calls be made to the outside. Also called a
house telephone or house phone.

closed competitive selection A competitive
process in which the owner (or his representative)

limits the lists of bidders on a building contract to
those he has selected for bidding.

closed construction Said of a building com-
ponent, building system, or building which is
manufactured in such a way that various portions
cannot be readily inspected at the installation
site without their disassembly or destruction.

closed cornice l.A boxed cornice. 2. A wood
cornice which projects only slightly and has no sof-
fit, having only a frieze board and crown molding.

closed cornice

closed eaves Eaves in which projecting roof
members are not visible, being closed from view
by boarding.

closed impeller In a pump, an impeller having
two shrouds (i.e., two disks enclosing the
impeller vanes). Such a pump usually requires
little maintenance and usually retains its operat-
ing efficiency longer than a pump having an
open impeller.

closed joint Between adjacent slabs of stone, a
joint that is invisible or barely visible.

closed list of bidders See invited bidders.

closed mortise Same as blind mortise.

closed newel The central shaft of a turning
stair when constructed within a continuous
enclosing wall, either hollow or solid.

closed shaft A shaft roofed or enclosed at the
top.

closed sheathing See closed sheeting.

closed sheeting, closed sheathing, tight
sheeting A continuous frame with vertical or
horizontal sheathing planks placed side by side to
form a continuous retaining wall used to hold up
the face of an excavation.

220

closer reinforcement

closed sheeting

closed shelving In cabinets, shelving which is

concealed by a door.
closed shop A construction project operating

under a work system that requires membership

in a particular union as a necessary condition of

employment.

closed specifications Specifications stipulat-
ing the use of specific products or processes with-
out provision for substitution.

closed stair A box stair.

closed stair string Same as close string.

closed string Same as close string.

closed string stair A stair constructed with
close strings so that the treads are not visible
from a side view of the stair.

closed string stair

closed system A heating or refrigeration pip-
ing system in which the circulating water or
brine is completely enclosed and under pressure
above atmospheric.

closed valley Same as concealed valley.

closed water piping system A water piping
system in which a check valve or other device
prevents the return of water to the water supply
system.

close-grained, close-grown See narrow-
ringed.

close nipple A nipple having no shoulder (i.e.,
no unthreaded portion) and having the shortest
possible length permitted by standard practice.

close nipple

closer 1 . The last brick, block, stone, or tile laid in
a horizontal course; may be either a complete unit
or one trimmed on the site. 2. A stone course run-
ning from one windowsill to another (a variety of
stringcourse). Also see king closer, queen closer.

THREE-QUARTER CLOSERS

QUARTER

CLOSERS

THREE-QUARTER CLOSERS

closer, 1

closer mold A temporary wood form used as a
guide in cutting brick to a specific size.

closer reinforcement A metal plate which is
applied to a door or frame to provide additional
strength for the attachment of a door closer.

221

closer reinforcing sleeve

closer reinforcing sleeve A plate which
reinforces the rabbeted soffit and both faces of a
doorframe.

close-sheeted See close-boarded.

close sheeting Same as closed sheeting.

close string, close stringer, closed stringer,
curb string, housed string A staircase
string whose upper edge is straight and parallel to
its lower edge; the tread and riser ends are housed
in the face of the string and are concealed.

close studding Construction in which the
studs are placed relatively close and the inter-
vening spaces are plastered.

closet l.A small enclosed storage area. 2. A
small private room, often off a bedroom.

closet bolt A bolt having a low circular head of
extra large diameter which is cupped on the
underside so that it is sealed against the surface
when the bolt is tightened; used to fasten a water
closet bowl to the floor.

close timbering The lining of an excavation or
trench with boards having no space between
them.

closet lining Red cedar boards whose odor
repels moths; used to line closets.

close tolerance A tolerance closer than stan-
dard tolerance.

closet pole, closet rod A straight, round rod
installed in a clothes closet to hold clothes hangers.

closet screw A long screw having a detach-
able head; used to fasten a water closet bowl to
the floor.

closet valve The valve which controls the
flushing cycle of a tank-type water closet.

close-up casement hinge A hinge similar to
an extension casement hinge but having its
hinge pin closer to the face of the casement, 1.

closing costs Those costs incidental to a trans-
fer of title from seller to buyer and execution of
a mortgage on a property, e.g., legal and record-
ing fees and title insurance.

closing device, automatic closing device,
self-closing device 1 . A mechanism designed
to ensure that an open fire door will close and
latch in the event of a fire. 2. A device which
ensures that a door will return to its closed posi-
tion after being opened.

closing jamb Same as strike jamb.

close-up casement hinge

closing ring A metal ring fastened to a door;
used to pull it shut.

closing ring

closing stile
closure bar

Same as lock stile.

Of a stair, a flat metal bar con-
nected to the top and/or bottom surface or edge
of a stringer along a wall; used to close gaps
between the stringer and the wall.

closure strip A preformed asphalt or elas-
tomeric filler strip used to close the opening in
corrugated sheets at eaves, the lower edge of sid-
ing, at window beads, and the like.

clothes chute A laundry chute.

cloudiness The lack of clarity or transparency
in a paint or varnish film.

clout l.A metal plate attached to a moving
wood member to protect it from abrasion. 2. A
clout nail.

clout nail A nail having a large flat head, a
round shank, and a long side point or duckbill

222

coal house

point; used for fastening sheet metal, asphalt-
prepared roofing, plasterboard, etc.
closure brick Same as closer, 1 .

dr., Clr, Clr. In the lumber industry, abbr. for
"clear."

CLS Abbr. for "Canadian lumber sizes."
club hammer In stoneworking, a short-
handled, heavy hammer usually having a round
or octagonal face.

chinch A stiff, rigid clay or a chalk, used in

early British construction.
cluster development See cluster housing.

clustered column A number of columns
which are grouped together and physically con-
nected so they act as a single structural element.

clustered column

clustered pier A pier, 1 composed of a number
of shafts grouped together, usually around a cen-
tral, more massive, shaft or core.

cluster housing Dwellings grouped closely
together to form relatively compact units. The
space between clusters usually is allocated to
pedestrian circulation and cooperative recre-
ational use. This pattern normally results in a
higher density of land use than that of a conven-
tional subdivision layout.

clutch A device which permits the drive train
of a machine to be connected to, or discon-
nected from, a prime source of power; usually

clustered pier

operates on a mechanical principle with friction
surfaces that can be joined or separated, but
other types include a fluid coupler.

cm Abbr. for "centimeter."

CM Abbr. for "center matched."

CMP On drawings, abbr. for "corrugated metal
pipe."

CMU Abbr. for concrete masonry unit.

CND On drawings, abbr. for conduit.

CNRC Abbr. for "Canadian National Research
Council."

CO 1. Abbr. for change order. 2. Abbr. for cer-
tificate of occupancy. 3. Abbr. for cleanout. 4.
Abbr. for cutout.

coach bolt Same as carriage bolt.

coach house, carriage house A building
or part thereof for housing carriages when not
in use.

coach-mounting steps A small elevated
platform on which a person would step when
mounting or dismounting from a coach or car-
riage; often set near the entrance to a house.

coach screw See lag bolt.

coak 1. A projection from the end of a piece of
wood or timber which fits into a hole in another
piece to join them. 2. A dowel or hardwood pin
through overlapping timbers.

coalescence The formation of a film of resinous
or polymeric material when water evaporates
from an emulsion or latex system, permitting
contact and fusion of adjacent latex particles.

coal house A subsidiary building for the storage
of coal; often connected to a blacksmith's shop.

223

coal-tar felt

coal-tar felt A felt that has been saturated with
refined coal-tar pitch.

coal-tar pitch, tar A dark brown to black
hydrocarbon obtained by the distillation of coke-
oven tar; softening point near 150°F (65°C);
used in built-up roofing as a waterproofing agent.

coaming A frame or curb around an opening in
a roof or floor, raised above the surrounding level
to prevent the flow of water into the opening.

coarse aggregate Aggregate retained on a
4-76-mm (No. 4) sieve. Also see crushed gravel,
crushed stone, gravel, pea gravel.

coarse filter In an air-conditioning system, same
as prefilter.

coarse fraction That fraction of the solid par-
ticles in a soil sample having grain sizes larger
than a No. 200 sieve, i.e., greater than 0.003
inch (0.075 mm) in diameter.

coarse-grained l.See wide-ringed. 2. See
coarse-textured.

coarse stuff A mixture of lime putty, hair, and
sand; used as a base-coat plaster.

coarse-textured, coarse-grained, open-
grained Descriptive of wood having an open,
porous cell structure that usually requires filling
to provide a smooth finish.

coarse-textured wood Any wood having

large pores.
coat A single layer of plaster, paint, or any type

of material applied to a surface.

coated bar A reinforcing bar that has been
coated to increase its resistance to corrosion.

coated base sheet, coated base felt A roof-
ing material consisting of asphalt-saturated felt
which is coated with a harder viscous asphalt to
increase its impermeability to moisture signifi-
cantly.

coated electrode, light-coated electrode

A filler-metal electrode used in arc welding
which consists of a metal wire having a light
coating to stabilize the arc.
coated glass Glass having a coating designed
to admit light over most of the visible range
but to block light in the ultraviolet and infrared
ranges; the coating reflects some of heat gener-
ated within a building so that it remains in the
building instead of largely being transmitted
through the window, thereby effecting a saving

ARC FLAME

LIGHT
COATED
ELECTRODE

ARC CORE

MOLTEN
PUDDLE

U^ v '^^l i ^^' DENETRAT,0N

-CRATER^

BASE METAL

coated electrode

of heat during the winter; often applied on glaz-
ing in a double window construction.

coated macadam See bitumen macadam.

coated nail An enameled nail, cement-coated
nail or mechanically galvanized nail.

coating A layer of material which is applied to a
surface to decorate, preserve, protect, seal, or
smooth the substrate; usually applied by brush-
ing, spraying, mopping, troweling, or dipping.

coat rack A storage rack for coats and hats; may
include a boot rack, umbrella stand, and drip tray.

coatroom l.A cloakroom. 2. A room for the
deposit or checking of outer garments.

coaxial cable 1 . A cable consisting of two con-
centric conductors (an inner conductor and an
outer conductor) insulated from each other by a
dielectric; commonly used for the transmission
of high-speed electronic data and/or video sig-
nals. 2. A single transmission cable having a
concentric conductor and shielding; used for
communications transmission, such as for televi-
sion signals.

coaxial cable

cob A mixture of straw, gravel, and unburnt
clay; used esp. for walls.

cobble, cobblestone l.A rock fragment
between 2Vi and 10 in. (64 and 256 mm) in
diameter, used for rough paving, walls, and
foundations. 2. Coarse aggregate for concrete,

224

coefficient of subgrade friction

having a nominal size in the range 3 to 6 in.
(75 to 150 mm).

cobblestone house A house whose rubble-
work walls are surfaced with cobblestone.

cob wall A wall formed of unburnt clay mixed
with chopped straw, gravel, and occasionally
with layers of long straw, in which the straw acts
as a bond.

cobwebbing Formation of strands, resembling
cobwebs, of dried or semidried paint when
expelled from a spray gun; usually caused by
highly polymerized binders.

cochlea l.A tower for a spiral staircase. 2. A
spiral stair.

cochleary, cochleated Spirally or helically
twisted, as a spiral stair.

cocina In Spanish architecture, a kitchen.

cock 1. See faucet. 2. A stopcock.

cock bead A bead which is not flush with the
adjoining surface but is raised above it.

cocking 1 . Same as cogging. 2. Tipping sideways.

cocking piece See sprocket.

cockle-shell cupboard Same as shell-headed
cupboard.

cockle stair A spiral stair.

cockloft A garret under a roof, above the high-
est ceiling. Also see loft, 2.

cockscomb A drag.

cockspur fastener A fastener on a casement
window.

coctile Made by baking, as porcelain or a brick.

coctilis Said of an ancient Roman building con-
structed of brick hardened in a kiln, as opposed
to brick hardened in the sun.

code l.A legal instrument adopted within a
political jurisdiction (such as a town, county,
state, province, parish, etc.) that prescribes the
minimum acceptable levels of the design, con-
struction, installation, and performance of mate-
rials, components, devices, items of equipment,
appliances used in a building, or building sys-
tems and/or subsystems. 2. A published body of
rules and regulations for building practices,
materials, and installations, designed to protect
the health, welfare, and safety of the public, such
as a building code, health code, etc. Codes estab-
lished by municipal, state, or federal authorities
usually have the power of law.

coded fire-alarm system A fire-alarm system

in which an alarm signal is sounded in a prede-
termined coded sequence, usually indicating
the area in a building where the alarm has been
initiated.

code of practice A technical document set-
ting forth standards of good construction for var-
ious materials and trades, but does not have the
force of law.

COEF On drawings, abbr. for "coefficient."

coefficient of beam utilization The ratio of
the luminous flux reaching a specified area from
a floodlight or similar luminaire to the total
luminous flux of the beam.

coefficient of discharge l.The ratio of the
actual discharge of water through an opening to
its corresponding theoretical value. 2. The ratio
of effective area to the free area of an air diffuser.

coefficient of elasticity Same as modulus of

elasticity.
coefficient of expansion The change in

dimension of a material per unit of dimension

per degree change in temperature.

coefficient of friction The ratio of the force
causing a body to slide along a plane (in the
direction of sliding) to the normal force pressing
the two surfaces together.

coefficient of heat transmission Same as
coefficient of thermal transmission.

coefficient of hygrometric expansion See
hygrometric expansion.

coefficient of light transmission See lumi-
nous transmittance.

coefficient of performance l.In a heat
pump, the dimensionless ratio of heat produced
to the energy supplied. 2. In a refrigerating unit,
the dimensionless ratio of the heat removed to
the energy expended in removing it.

coefficient of runoff In the design of storm-
water drainage systems, a coefficient which
accounts for storm-water losses attributed to
evaporation, infiltration, and surface depressions.

coefficient of static friction The coefficient
of friction where the force in the direction of
sliding is that necessary to initiate sliding.

coefficient of subgrade friction The coeffi-
cient of friction between a slab and the subgrade
on which it rests.

225

coefficient of subgrade reaction

coefficient of subgrade reaction The ratio
of load per unit area on soil to the corresponding
deformation.

coefficient of sound absorption See sound
absorption coefficient.

coefficient of thermal expansion Same as
coefficient of expansion.

coefficient of thermal transmission The
amount of heat transferred through a unit area of
a partition per hour, per degree temperature dif-
ference between the air on the two sides; e.g.,
the number of Btu per square foot per hour per
degree Fahrenheit.

coefficient of utilization, Brit, utilization
factor. The ratio of luminous flux received on
the work plane to the total luminous flux emit-
ted by the source.

coefficient of variation The standard devia-
tion expressed as a percentage of the average.

coelanaglyphic relief Carving in relief in
which no part of the figure represented projects
beyond the surrounding plane.

coenaculum In ancient Roman houses, the
dining room or supper room, or any of the upper
rooms in which food was eaten.

coenatio Same as cenatio.

coenobium A community of monks living
under one roof.

coffer, lacunar l.One panel in coffering.
2. A caisson, 2.

cofferdam A temporary watertight enclosure
around an area of water or water-bearing soil, in
which construction is to take place, bearing on a
stable stratum at or above the foundation level
of new construction. The water is pumped from
within to permit free access to the area.

coffered ceiling Same as coffering, 1.

coffering 1. Ceiling with deeply recessed panels,
often highly ornamented. 2. Similar effects exe-
cuted in marble, brick, concrete, plaster, or stucco.
Also see caisson, 2.

coffer panel One of the many panels in coffer-
ing, 1.

cog In a cogged joint, the solid portion which is
left in a timber after it has been notched.

cogeneration In a building, the on-site electric
power generation utilizing both the electrical

coffering, 1

power and steam or hot water which is devel-
oped; in some municipalities in the US, if excess
electrical power is generated, it may be sold to
the utility.
cogged joint A carpentry joint formed by two
crossed structural timbers, each of which is
notched at the place where they cross.

cogged joint

cogging, cocking The joining of two timbers
which are notched, cogged, or indented.

cohesion 1. The molecular forces of attraction
by which the body of an adhesive or sealant is
held together; the internal strength of an adhe-
sive or a sealant. 2. Of soil particles, the sticking
together of particles whose forces of attraction
exceed the forces that tend to separate them.

cohesionless soil A soil which when unconfined
has no significant cohesion when submerged, and
no significant strength when air-dried.

cohesive failure The tearing apart of a sealant
as the joint expands if its adhesive (bond) capa-
bilities exceed its cohesive capabilities.

cohesive soil 1 . A soil which when uncon-
fined has appreciable cohesion when submerged,
and considerable strength when air-dried. 2.
Soil, such as clay, whose particles adhere to each
other by means of adhesive and cohesive forces.

coign See quoin.

coil A heat exchanger in the form of pipe or
tubing in any of various configurations; fins may

226

cold joint

be attached to dissipate heat; also called an
attemperator.
coiled expansion loop Same as expansion
bend.

coin, quoin 1 . The corner of a building. 2. The
stones or bricks which form the corner. 3. A
wedge.

coke grating A special grating fitted into an
ordinary fireplace to burn No. 3 grade coke, Vi to
V/a, in. (1.3 to 3.1 cm) size, generally fitted with
an integral gas burner to facilitate lighting of
fuel.

COL On drawings, abbr. for column.

colarin Same as collarino.

cold-air return In an air-conditioning system
in a house of wood frame construction, a return
air duct which utilizes the space between joists.

COLD-AIR
REGISTER

SUB FLOOR

CUT PLATE
AND

SUBFLOOR

JOIST

METAL

COLD -AIR
RETURN DUCT

cold-air return

cold bending, cold gagging The bending of
metal without the application of heat, as the
bending of metal pipe.

cold bridge Any type of break in a continuous
thermal insulation barrier, leaving an opening
that "short-circuits" the thermal insulation.

cold-cathode lamp An electric-discharge lamp
which produces light by means of a glow
discharge; operates at relatively low current and
high voltage; has cylindrical electrodes which
operate at a low temperature.

cold cellar Part of a cellar where root crops are
stored during the winter at cold, but above-freez-
ing, temperatures.

cold check The formation of fine cracks in

wood finishes when subjected to cycles of heat

and cold.
cold chisel A chisel with a cutting edge formed

of tempered steel; used for cutting metal which

has not been softened by heating.

cold chisel

cold cut, cold cutter A cold chisel mounted
on a handle like a hammer; struck with a maul.

cold-drawn Descriptive of metal which has
been drawn through a set of dies designed to
reduce its cross-sectional area without heating
the metal. The process is used in the fabrication
of rod, tubing, and wire.

cold-driven rivet A rivet that is driven cold,
without preheating.

cold-finished bar A metal bar, brought to its
final dimensions by cold-working, which results
in improved surface finish and dimensional tol-
erance.

cold-finished steel Carbon steel which has
been cleaned and pickled and then rolled or
drawn through dies to produce a dimen-sionally
accurate section with an improved surface finish
(and often with other improved properties).

cold flow 1 . The permanent deformation of a
material under constant stress. 2. At room tem-
perature, the continuing dimensional change
under static load that follows initial instanta-
neous deformation.

cold forging The forging of metal without the
application of heat.

cold-formed member A structural steel
member formed without the application of heat.

cold-formed steel construction That type
of construction made up entirely, or in part, of
steel structural members cold-formed to shape
from sheet or strip steel, such as roof deck, floor
and wall panels, floor joists, studs, roof joists, or
other structural elements.

cold gagging See cold bending.

cold glue A glue which is a cold-setting adhesive.

cold joint A joint formed when a concrete sur-
face hardens before the next batch of concrete is

227

cold-laid mixture

placed against it; characterized by a poor bond
unless special procedures are observed.
cold-laid mixture Any mixture which may be
spread and compacted at normal atmospheric
temperature.

cold mix Asphaltic concrete for placement
without heat; prepared with a relatively light
and slow-curing asphalt; hardens to a state less
firm and durable than hot-mixed asphaltic
concrete.

cold molding 1 . A procedure in which a com-
position is shaped at room temperature and
cured by subsequent baking. 2. The material
used in this procedure.

cold patch An application of asphaltic cold
mix over a small area.

cold pie Mortar in excess of that actually used
in laying a masonry unit.

cold pressing The bonding of components by
pressure without the application of heat.

cold-process roofing A bituminous roofing
membrane which consists of layers of coated
felts that have been bonded with cold-applied
asphalt roof cement and surfaced with an emul-
sified or cutback asphalt roof coating. Also see
asphalt prepared roofing.

cold riveting Driving rivets cold, without pre-
heating.

cold-rolled Descriptive of metal that has been
formed by rolling at room temperature, usually
to obtain improved surface finish or higher ten-
sile strength.

cold room A room where low temperatures
are maintained; a refrigeration room.

cold saw A saw for cutting metal at ordinary
room temperatures, as a metal-cutting circular
saw.

cold set A type of short steel chisel having a flat
edge; used in cutting bars, flattening sheet-metal
seams, etc.

cold-setting adhesive An adhesive that sets
at temperatures below 68°F (20°C).

cold-shortness Brittleness in metal at room
temperatures.

cold shut In a casting, a defect having the
appearance of a fold or wrinkle.

cold-solder To solder without the application
of heat, as with copper amalgam.

cold solder joint A faulty joint in electric
wiring which results from the application of
insufficient heat at the joint; the solder merely
covers the joint and is not physically united
with it.

cold-start lamp Same as instant-start fluores-
cent lamp.

cold-storage cooler An insulated room which
is artificially cooled but whose temperature is
never below 30°F(-1.1°C).

cold-storage door A heavy, thermally insu-
lated door, fully gasketed at the frame; used on
refrigerators and freezers.

cold strength Of refractory concrete, the com-
pressive or flexural strength determined prior
to firing.

cold-water paint A mixture of pigment and
binder dissolved or dispersed in cold water.

cold 'welding The joining of metals (such as
aluminum) at room temperature by subjecting
thoroughly cleaned metal surfaces to pressure;
coalescence is produced solely by the applica-
tion of mechanical force.

cold-worked steel Descriptive of steel which
has been rolled, drawn, or twisted at normal
ambient temperatures; used for steel bars and
wire in reinforcement for concrete.

cold working The plastic deformation of
metal at or near room temperature; this shaping
is usually carried out by drawing, pressing,
rolling, or stamping.

cold 'wrap A type of corrosion-proof tape which
is wrapped around a pipe without the application
of heat.

coliseum See colosseum.

collapse Mechanical failure of cells in wood,
usually caused by abnormal or forced drying.

collar 1 . A metal cap flashing for a vent pipe pro-
jecting above a roof deck. 2. A raised band which
encircles a metal shaft, a wood dowel, or a
wooden leg. 3. A raised section to reinforce a
metal weld. 4. A collarlno. 5. The reinforcing
metal of a nonpressure thermit weld. 6. Same as
escutcheon.

collar beam, spanpiece, sparpiece, top
beam, wind beam A horizontal member
which ties together (and stiffens) two opposite
common rafters, usually at a point about halfway
up the rafters in a collar beam roof.

228

Colonial architecture

collar beam

collar beam roof, collar roof A roof
supported by rafters tied together by collar
beams.

collar brace A structural member which rein-
forces a collar beam in medieval roof framing.

collared hole A hole of shallow depth, drilled
into a material to prevent slippage of the bit
when a deeper hole is drilled.

collaring 1 . Pointing with cement mortar
under the overhangs of tiles or slabs. 2. The
drilling of a collared hole.

collarino 1 . A necking, as on a classic Tuscan,
Doric, or Ionic capital; also called a collar, 4.
2. An astragal.

collar joint l.The joint between a roof rafter
and a collar beam. 2. The vertical joint between
masonry withes.

collar tie In wood roof construction, a timber
which prevents the roof framing from changing
its shape.

collected plants Plants that are gathered from
sources other than a working nursery.

collecting safe area In an emergency, a safe
area that receives occupants from the assembly
space it serves, as well as from other safe areas.

collection hopper A cart with wheels used to
funnel concrete into drop chutes and elephant
trunks, which may or may not be attached;
often used alone for placing concrete in shallow
restricted areas.

collector See solar collector.

collector box In roof drainage, a transition
piece between a downspout and gutter.

collector street One which functions as a
feeder from an area of limited traffic to a major
street or highway.

Collegiate Gothic A secular version of
Gothic architecture, characteristic of the older
colleges of Oxford and Cambridge. Adopted in
the late 19th and early 20th centuries by a num-
ber of other colleges in other countries.

Collegiate Gothic

colloid A gelatinous substance so finely divided
that it remains in suspension when dispersed in
a liquid.

colloidal concrete Concrete whose aggregate
is bound by colloidal grout.

colloidal grout A grout which has artificially
induced cohesiveness or ability to retain the dis-
persed solid particles in suspension.

colloidal mixer A mixer designed to produce
colloidal grout.

collusion A secret agreement for illegal or
fraudulent purposes.

colluviarium In ancient Rome, an opening
made at regular intervals in an aqueduct, for
ventilation.

Cologne earth, Cologne brown A type of
Vandyke brown made from roasted American
clays which contain ochre and bituminous
matter.

colombage Half-timber construction.

colonette, colonnette l.A small column,
usually decorative. 2. In medieval architec-
ture, a thin round shaft to give a vertical line
in elevation, or as an element in a compound
pier.

Colonial architecture Architecture trans-
planted from the motherland to overseas
colonies. For examples see American Colonial
architecture, Dutch Colonial architecture,
English Colonial architecture, French Colonial
architecture, German Colonial architecture,
Spanish Colonial architecture. Compare with
Colonial Revival.

229

colonial casing

colonial casing A type of decorative, exposed
trim molding.

colonial casing

Colonial joint Same as tooled joint,
colonial panel door A door having stiles,

rails, and a mutin which form frames around

recessed panels.

colonial panel door

Colonial Revival An architectural mode that
reuses selected aspects of earlier colonial proto-
types, especially from around 1870 onward. In the
United States, when this term is used without ref-
erence to a country of origin (simply as Colonial
Revival), it usually refers to American Colonial
Revival, based on prototypes in the English
colonies in America. Of these prototypes, the
Georgian and the Federal style (Adam style) are the
most widely imitated, giving rise to the terms
Georgian Revival and Federal Revival (Adam
Revival). Colonial Revival houses are usually the
result of a rather free interpretation of their proto-
types; they tend to be larger than, and may differ
significantly from, the houses they seek to emu-
late, often exaggerating architectural details. For
descriptions of other types of colonial revival archi-
tecture, see Dutch Colonial Revival, Chateauesque

style, French Eclectic architecture, Spanish Colo-
nial Revival, Mission Revival, Pueblo Revival.
Also see Neo-Colonial architecture.

colonial siding Wide, square-edged siding boards
used extensively in early American construction.
Also see weatherboarding.

colonial siding

colonnade A number of columns arranged in
order, at intervals called intercolumniation,
supporting an entablature and usually one side
of a roof.

colonnade

colonnette See colonette.
colophony See rosin.

color (perceived) That attribute of visual per-
ception that can be described by names such as
yellow, red, blue, etc., or some combination of
such names, (of an object) A characteristic of the
appearance of an object, surface, etc., distinct

230

columna cochlis

from its form, gloss, shape, size, or position;
depends on the spectral composition of the inci-
dent light, on the spectral reflectance or trans-
mittance of the object, and on the spectral
response of the observer.

color chart A chart showing a systematic array
of colors or their representations.

color code A system of colors adopted for iden-
tification of pipes, cables, wiring, or the like.

colored aggregate Sand, gravel, or other aggre-
gate chosen for the coloration it can impart to
concrete in an exposed-aggregate finish.

colored cement A cement to which color pig-
ment has been added.

colored concrete 1. Concrete tinted during
its mixing by colored cement or color pigments.
2. Hardened concrete which has been subjected
to a colored wash.

colored finishes In plastering, finish coats
containing colored aggregates or color pigments;
the color is intimately mixed throughout.

color frame A metal frame at the front of a
luminaire, used to support transparent colored
material, esp. in spotlights and floodlights.

coloring pigment 1 . See pigment. 2 . See stainer.

color pigment l.A natural or synthetic pig-
ment or stainer, usually iron or chromium
oxides, added to either mortar or block concrete.
2. See pigment, 1.

color rendering index (CRI) A measure of
the closeness with which a light approximates
daylight having the same color temperature.

color retention The ability of a paint or var-
nish film to retain its original color appearance
and not fade with age or exposure to sunlight.

color selection log See finish and color selec-
tion log.

color temperature Of a light source, the
absolute temperature at which a blackbody, 1
radiator must be operated to have a chromacity
equal to that of the light source.

colossal column A column that is more than

one story in height.
colossal order, giant order An order more

than one story in height.
colossal pilaster A pilaster that extends the

full height of a building containing two or more

floors.

colosseum, coliseum I. {cap.) The Flavian
amphitheater in Rome. 2. Any large Roman
amphitheater. 3. Now, any large sports arena,
open or roofed.

colosseum, 1 showing seating and plan at various levels

colour See color.

columbage In French Vernacular architecture
of Louisiana, timber-framed construction with
diagonal bracing of the framework; the space
between the structural timbers was usually filled
with bousillage or pierrotage.

columbarium One or a series of niches, intended
to receive human remains. (See illustration p. 232.)

columella Same as colonette.

column 1. In structures, a relatively long, slen-
der structural compression member such as a
post, pillar, or strut; usually vertical, supporting a
load which acts in (or near) the direction of its
longitudinal axis. 2. In classical architecture, a
cylindrical support consisting of a base (except
in Greek Doric), shaft, and capital; either mono-
lithic or built up of drums the full diameter of
the shaft. 3. A pillar standing alone as a monu-
ment. (See illustration p . 232.)

columna cochlis In ancient Rome, a column
with a spiral staircase around its center line.

231

columna rostrata

columbarium

column, 2 Tuscan order

columna rostrata Same as rostral column.
columna triumphalis See triumphal column.

column baseplate A horizontal plate beneath
the bottom of a column; transmits and distrib-
utes the column load to the supporting material
below the plate.

column cage An assembly of reinforcing bars
and ties for use in constructing a reinforced con-
crete column.

column capital A mushroom-like enlarge-
ment of reinforced concrete, at the upper end of
a column, designed and built to act as an integral
unit with the column and the floor slab above so
as to increase the shearing resistance.

column casing Any form of enclosure of a
steel column which provides a prescribed fire
rating, e.g., a boxed enclosure fabricated of a
fire-rated material, such as gypsum board; also
see caged beam.

column clamp A fastening device for a form
for a concrete column, holding together the
sides of the form.

column curve The graphical relationship
between the axial strength of a column and its
slenderness ratio.

column footing See footing.

column head Same as column capital.

columniation Systems of grouping columns in
classical architecture. Also see intercolumniation.

column side In a form for a concrete column,
one of the vertical panels.

column splice A splice which unites two
columns.

column strip That portion of a flat slab, over
the columns, which consists of the quarter
panels on both sides of the column center line.

colymbethra In a Greek church, the room or
font for administering baptism.

COM Abbr. for "customer's own material."

Com, Com. In the lumber industry, abbr. for
"common."

comb 1. Combing, 1. 2. A drag, 1.3. Any tool
used to produce combing, 2, 3.

COMB. On drawings, abbr. for "combination."

comb board A saddle board having notches
along its upper edge.

comb ceiling A ceiling that sags inwardly like
a tent. Also called a camp ceiling or tent ceiling.

comb cut Same as plumb cut.

combed Same as dragged.

combed-finish tile Tile whose face surfaces
are altered by more or less parallel scratches in
manufacture to give increased bond for mortar,
plaster, or stucco.

combed joint A finger joint.

comb»grained See edge-grained, quartersawn.

232

combined aggregate

combination column A column in which a
structural steel member, designed to carry part of
the load, is encased in concrete of such quality
and in such manner that the combination of
steel and concrete will carry the total load.

combination door An exterior door having
interchangeable screen and glass storm-panel
inserts; provides a glazed storm door in winter
and a screened door in summer.

combination faucet A device in which the
flow of water from hot and cold water pipes is
controlled and is drawn from a common spout.

combination faucet

combination fixture A fixture which com-
bines one or more kitchen sinks and laundry
trays in a single unit.

combination frame In light wood-frame
buildings, a combination of a full frame and a
balloon frame.

combination ladder A portable ladder which
may be used as a stepladder, extension ladder,
single ladder, or trestle ladder.

combination plane 1. A plane having inter-
changeable cutters for various applications in
shaping. 2. A plane having a guide which can be
changed from one side to the other, or adjusted
vertically.

combination pliers Slip-joint pliers having
serrated faces for gripping rounded surfaces
such as pipe, together with blades for cutting
wire.

combination pliers

combination sheet In roofing, a fiberglass felt

integrally attached to kraft paper.
combination square An adjustable carpenter's

tool consisting of a steel rule which slides through

combination square

an adjustable head; may be used as a try square,
miter square, level, marking gauge, plumb, and
straightedge.
combination stair A stair in which access to
the first landing is provided by a supplementary
service stair as well as the main flight.

;

combination stair

combination waste and vent system A

special system of venting in which the waste pip-
ing is purposely oversized; intended as an eco-
nomical means of providing adequate protection
of fixture traps against loss of seal in extensive
installations where the individual venting of fix-
ture drains would be impractical or uneconomi-
cal; serves both as a waste pipe and vent pipe.

combination window 1 . A window equipped
with removable or interchangeable screen and
glass sections that make it suitable for either sum-
mer or winter use. 2. A window having several
types of sash.

combined aggregate A mixture of fine and
coarse aggregate for a concrete.

233

combined-aggregate grading

combined-aggregate grading The particle-
size distribution of a mixture of fine and coarse
aggregates.

combined building drain A building drain
that conveys the drainage of both sewage and
storm water.

combined building sewer A sewer that
receives both storm water and sewage.

combined dry-pipe/preaction system A
fire sprinkler system which combines automatic
sprinklers (i.e., sprinkler heads) attached to a
piping system containing air under pressure con-
trolled by a fire detection system installed in the
same areas as the sprinklers. See dry-pipe sprin-
kler system and preaction sprinkler system.

combined footing A footing which supports
more than one column load.

combined frame A doorframe having fixed
panes of glass flanking one or both sides of the
door.

combined load Two or more different types of
loads (such as dead load, live load, or wind load)
on a structure, occurring simultaneously.

combined sewer A sewer which carries both
sanitary sewage and storm water.

combined stack A soil pipe that carries both
soil and waste discharges.

combined stresses A stress state which can-
not be represented by a single component of

stress.

combing l.In roofing, the topmost row of
shingles which project above the ridge line; the
uppermost ridge on a roof. 2. Using a comb or
stiff bristle brush to create a pattern by pulling
through freshly applied paint. See antiquing. 3.
Scraping or smoothing a soft stone surface.

combplate The toothed portion of the sta-
tionary threshold plate at both ends of an esca-
lator or moving walk, designed to mesh with
the grooved surface of the moving steps or
tread way.

combustibility The ease with which a mate-
rial will burn when subject to heat.

combustible Capable of undergoing combus-
tion in air, at pressures and temperatures that
might occur during a fire in a building.

combustion Any chemical process that pro-
duces light and heat as either glow or flames.

combustion liquid A liquid having a flash
point at or above HOT (60°C) and below 200°F
(93.4°C).

combwork In plasterwork, 1 or pargeting,
descriptive of an exposed plaster surface that has
had a tooth-like tool dragged across it before it
hardens.

come»along A tool for spreading concrete,
similar to a hoe; has a blade approx. 20 in. (50
cm) wide and 4 in. (10 cm) high.

comedor A dining room in a Spanish Colonial
house.

comfort chart A chart which relates effective
temperature, dry-bulb temperature, wet-bulb
temperature, and air movement to human com-
fort; comfort zones are indicated on such a
chart.

comfort station A building or part thereof
where toilet and lavatory facilities are available
for public use.

comfort zone In a heating, ventilating, and
air-conditioning system, the range in tempera-
ture, humidity, and air movement that most of
the building's occupants consider to be comfort-
able.

commaunder Same as a blockhouse.

commercial bronze An alloy containing
90% copper, 10% zinc; so called because of its
bronze color; esp. used in weatherstripping.

Commercial Italianate style See Italianate
style.

commercial projected window A type of
steel projected window; intended for commercial
and industrial buildings which do not require
interior trim or finishing around the window.

Commercial style A style of commercial
architecture developed by the Chicago School,
applied primarily to multistory office buildings
and mercantile buildings constructed from about
1875 to 1930. Usually characterized by a tripar-
tite scheme consisting of a base that is one to
three stories high, a shaft many stories high; and
a cap, usually one to three stories high that tops
the structure; a flat roof; an overhanging cor-
nice; unadorned fenestration, most often with
large rectangular windows (for example, see
Chicago window); bay windows with decorative
spandrels, 1. Sometimes called Chicago Com-
mercial style.

234

common nail

commercial tolerances The plus and/or
minus allowances that are acceptable with a
specified dimension.

Commission Internationale de l'Eclairage

International Commission on Illumination.
Abbr. CIE.

commode step One of two (or more) steps at
the foot of a flight of stairs which have curved ends
projecting beyond the newel and the string, 1.

common A large plot of grassy, fenced-in, pub-
licly owned land, generally at or near the center
of a village or town; in earlier eras, once shared
by the townspeople as a pasture.

common alloy An alloy that does not
increase in strength when heat-treated but may
be strengthened by strain hardening.

common American bond Same as common
bond.

common-and-cross bond A bond that is a
combination of cross bond, which describes the
masonry facing, and common bond which
describes the backing.

common area An area either within a build-
ing or outside a building which is intended for
use of all occupants of the building or a group of
buildings, but not for the free use of the general
public.

common ashlar A pick- or hammer-dressed
block of stone.

common bond A pattern of brickwork in
which every third, fifth, sixth, or seventh course
consists of headers (i.e., bricks laid horizontally

STRETCHERS

with their lengths perpendicular to the face of
the wall), and the other courses consist of
stretchers (i.e., bricks laid horizontally so that
their lengths are parallel to the face of the wall).
This pattern is widely used because it can be laid
relatively quickly.
common brass, high brass An alloy con-
taining 65% copper, 35% zinc; the most com-
mon of commercial wrought brasses.

common brick Same as building brick.

common dovetail, box dovetail, through
dovetail A dovetail joint in which the end

grain shows on both members.

common

bond

common dovetail

common excavation The excavation of
material that does not require blasting, such as
earth, in contrast to the excavation of solid rock.

common ground See ground, 1.

common house 1 . That part of a monastery in
which a fire was kept for the monks during the
winter. 2. A one -room cottage in Spanish Colo-
nial architecture of Florida, primarily in the first
half of the 18th century. Characterized by:
whitewashed tabby walls, a hipped roof that was
thatched with palmetto fronds; and a smoke
hole at the ridge of the roof; also see Saint
Augustine house.

common joist, bridging joist A joist on

which floorboards are laid; neither supports nor
is supported by another joist.

common lap Shingle roofing in which alter-
nate courses are offset one -half the width of a
shingle.

common lime Either hydrated lime or quick-
lime; used in plastering.

common nail A cut or wire low-carbon steel
nail, having a slender plain shank and a medium

235

common path of travel

diamond point; used in work where finish is
unimportant, as in framing.

common path of travel That portion of exit
access that the occupants are required to tra-
verse before two separate and distinct paths of
travel to two exits are available.

common pitch In a spiral stair, the pitch of
the fliers above and below the winders.

common purlin In timber-framed construc-
tion, one of a number of horizontal timbers that
are parallel to the ridge of the roof, and joined to
the principal rafters into which they are seated.
The upper surfaces of the common purlins and
the principal rafters are in the same plane. Also
see purlin.

common rafter In wood-frame construction,
one of a number of slanting structural members
(extending from the ridgeboard down to the
eaves) that support the roof; these members are
usually of the same size and evenly spaced along
the length of the roof ridge.

COMMON RAFTER

PLATE

common

rafte

common return An electrical conductor
which serves as the electrical return for more
than one circuit.

common roof A roof supported only by com-
mon rafters, without purlins.

common room l.A room or lounge for the
informal use of all members of a college. 2. A room
or lounge for the use of the patrons of an inn.

common vent See dual vent.

common wall See party wall.

communicating frame A double-rabbeted
frame (with the rabbets on each side) prepared
for two single -swing doors, one on each side of
the frame, which open in opposite directions.

communion rail In a church, a low railing
enclosing that part of an altar within which the

communicants are provided with a place to
kneel and receive Communion.

Communion table In Protestant churches, a
table used instead of an altar in the Communion
service.

community A group of people having common
rights, privileges, or interests, or living in the
same place under the same laws and regulations.

community center A building or group of
public buildings for the social, cultural, and edu-
cational activities of a neighborhood or entire
community.

community-facilities plan A graphic and
written statement depicting a desirable pattern
of public facilities (e.g., schools and parks)
within an area, including their character, loca-
tion, size, and service populations along with
their suggested construction schedule.

community plan See city plan and town plan.

community planning The process of plan-
ning a future community, or the guidance and
shaping of the expansion of a current community,
in an organized manner and with an organized
layout, taking into account such considerations
as convenience for its inhabitants, environmen-
tal conditions, social requirements, recreational
facilities, aesthetic design, and economic feasibil-
ity. Such planning includes a study of present
requirements and conditions as well as projec-
tions for the future, and often includes proposals
for implementing the plan.

COMP 1. On drawings, abbr. for "compensate."
2. On drawings, abbr. for "component." 3. On
drawings, abbr. for "composition."

compacted volume l.A measure of the vol-
ume of soil (or rocks) after its placement and
compaction in a fill. 2. The volume of a solid,
such as soil, after it has been subjected to com-
paction, 2.

compacted yards The compacted volume
measured in cubic yards.

compacting factor The ratio of the weight of
concrete which fills a container of standard size
and shape (when allowed to fall into it under stan-
dard conditions of test) to the weight of fully com-
pacted concrete which fills the same container.

compaction l.The process of inducing a
closer packing of the solid particles in freshly
mixed concrete or mortar during placement by

236

compass window

reducing the volume of voids, usually by vibra-
tion, centrifugation, tamping, or some combina-
tion of these actions. 2. A similar manipulation
of other cementitious mixtures, soils, aggregate,
or the like.

compaction pile One of a group of piles, driven
in a pattern, to compact a surface layer of loose
granular soil to increase its bearing capacity.

compactor l.A machine that uses weight,
vibration, or a combination of both, to achieve
compaction. 2. A motor-driven machine (usually
having one or more rams) which reduces the
volume of waste material by subjecting it to pres-
sure and forces it into a removable container.

compactor, 1

companion flange 1 . A pipe flange which has
been drilled so that it will fit the standard drilled
holes in a flanged pipe or fitting. 2. A pipe flange
that is suitable for connection with a flanged
valve or fitting.

company town A community whose inhabi-
tants depend predominantly on a single company
for their employment and for many of their per-
sonal and family needs. The company may own
and provide housing, schools, shopping facilities,
recreational facilities, as well as church and
library facilities for its workers and their families.

compartment A small space within a larger
enclosed area, often separated by partitions.

compartmentalization The division of a
building into fire-retardant sections, each of
which can be closed off from the others, thereby
impeding the spread of fire beyond its place of
origin.

compartment ceiling A ceiling divided into
panels, which are usually surrounded by moldings.

compartment wall British term for fire wall.

compass An instrument for drawing circles,
measuring the distance between two points, etc.;
consists of two pointed legs, movable on a joint

compass

or pivot, usually made so that one of the points
can be detached for the insertion of a pen,
extension, etc.

compass brick An arch brick.

compass-headed arch A semicircular arch.

compass plane A plane having a curved base-
plate (either concave or convex); for smoothing
curved woodwork.

compass rafter A rafter which is curved on
one or both sides.

compass roof l.A roof having curved rafters
or ties. 2. A form of timber roof in which the
rafters, collar beams, and braces of each truss
combine to form an arch.

compass saw A handsaw having a narrow
blade; used to cut small intricate shapes or cir-
cles of small radius.

compass saw

compass survey A traverse survey which
relies on the magnetic needle for orienting the
sequence as a whole or for determining the bear-
ings of the lines individually.

compass timber Timber that has been cut
from a branch having a smooth curve of the
required shape.

compass window l.A rounded bay window
that projects from the face of a wall; in plan, it
forms the segment of a circle; same as bow win-
dow. 2. A semicircular oriel window. 3. A win-
dow having a rounded, usually semicircular,
upper member.

237

compass work

compass work, circular work Joinery which
has circular forms within its overall design.

compatible materials In building construc-
tion, those materials that can exist in close
proximity without affecting each other detri-
mentally.

compensation 1 . Payment for services ren-
dered or products or materials furnished or deliv-
ered. 2. Payment in satisfaction of claims for
damages suffered.

compensator In fire sprinkler systems, a

device intended to minimize false alarms caused
by small increases in service pressure of the
water supply.

competitive bidding See open competitive
selection.

COMPF On drawings, abbr. for "composition
floor."

completed operations insurance Liability
insurance coverage for injuries to persons or
damage to property occurring after an operation
is completed but attributed to that operation;
does not apply to damage to the completed work
itself. An operation is completed (a) when all
operations under the contract have been com-
pleted or abandoned; or (b) when all operations
at one project site are completed; or (c) when
the portion of the work out of which the injury
or damage arises has been put to its intended use
by the person or organization for whom that por-
tion of the work was done.

complete fertilizer In landscape architecture,
a fertilizer that contains all the nutrients that
plants use in quantity, such as nitrogen, phos-
phorus, and potassium.

complete fusion In welding, fusion that has
occurred over the entire base-metal surfaces
exposed for welding and between all layers and
passes.

completion bond, construction bond,
contract bond The guarantee of a bonding
company that a contractor will perform and
deliver the work contracted for free of all
encumbrances and liens.

completion date In the contract documents,

the date of substantial completion of the work.
completion list See inspection list.
compliance See certificate of compliance.

compluvium The aperture in the center of the
roof of the atrium in a Roman house, sloping
inward to discharge rainwater into a cistern or
tank.

compluvium, B

compo 1. Any composition material. 2. Mortar
made with an appropriate proportion of cement,
lime, and sand. 3. Various plastic cements and
pastes which harden on exposure, as papier-
mache.

component depreciation Depreciation of a
building reckoned on the basis of the deprecia-
tion of individual elements of the building,
thereby accounting for the building's overall loss
in utility with time.

composite A combination of conventional
materials such as gypsum with reinforcement
fibers such as carbon or glass so as to provide the
material with greater strength.

composite arch An arch whose curves are
struck from four centers, as in English Perpen-
dicular Gothic; a mixed arch.

composite beam A structural beam composed
of different materials so interconnected that the
beam responds to loads as a unit.

composite board A type of hardboard, esp.
one fabricated for use in heat insulation.

Composite capital The topmost member of a
column of the Composite order; a Roman adap-
tation of a Corinthian capital, being much more
elaborate; consists of volutes and convex mold-
ing between them, somewhat similar to the

238

composition board

-Abacus
Volul*
Ecbincta

RUlicoluS

?-i«isrm$d

iffM

Composite capital

Ionic capital; has a circle of acanthus leaves
applied to the lower part of the bell used in the
Corinthian capital.

composite column A column in which a
metal structural member is completely encased
in concrete containing special and longitudinal
reinforcement.

composite construction A type of construc-
tion made up of different materials (such as
concrete and structural steel) or of members pro-
duced by different methods (such as cast-in-
place concrete and precast concrete).

composite door A door made of a core mate-
rial which is faced and edged with steel, wood, or
a plastic-laminated material.

composite fire door A flush-design fire
door; consists of a manufactured core material
with chemically impregnated wood edge band-
ing and untreated wood face veneers, or lami-
nated plastic faces, or surrounded by and
encased in steel.

composite girder l.See plate girder. 2. A

girder of composite construction,
composite joint A joint employing more than

one means to hold the elements together, e.g.,

welding and bolting.
composite metal decking Sheets of

corrugated-steel bonded securely with concrete

fill to produce a reinforced steel deck. Also

called a composite slab.
composite metal panel See sandwich panel.

Composite order In Classical architecture,
one of the five Classical orders; combines char-
acteristics of both the Corinthian and Ionic
orders; similar to the Corinthian order, but
much more embellished. The capital consists of
volutes borrowed, with modifications, from the
Ionic capital; the circle of acanthus leaves
applied to the capital is borrowed from the
Corinthian capital. See illustration under bases
for an example of a base of the Composite order.

Composite order

composite pile 1 . A pile comprised of different
materials, e.g., concrete and wood. 2. A pile
comprised of steel members which are fastened
together, end-to-end, to form a single pile.

composite sample A sample of material which
is obtained by blending two or more individual
samples.

composite structure A structural element in
which different types of materials share a load.

composite truss A truss whose compressive
members are timber and whose tension members
are metal (usually steel).

composite wall A wall built of a combination
of two or more masonry units of different types of
materials that are bonded together, one forming
the facing of the wall and the other the backup.

composition board A building board which is
fabricated of wood fibers, under pressure and at
an elevated temperature, usually with a binder.

239

composition joint

composition joint A bell-and-spigot joint that
is sealed with a combination of materials such as
cement and hemp, rope and rosin, etc.

composition mortar A plastic mixture of
cement, lime, sand, and water.

composition nail (Brit.) A brass nail used in
roofing, esp. to fix tiles and slates.

composition roofing See built-up roofing.

composition shingles See asphalt shingles.

compost A mixture usually consisting largely of
decomposed organic material; used for fertilizing
soil.

compound arch An arch formed by concen-
tric arches set within one another.

compound beam, built-up beam A rect-
angular beam composed of smaller timbers over
which planks are nailed on each side; the compos-
ite unit is joined together by bolting or by gluing.

BOLTS

compound beam

compound column Same as clustered column.

compound order Same as Composite order.

compound pier, compound pillar A pier
composed of a conjunction of colonettes, gener-
ally attached to a central shaft; a clustered col-
umn. Also see bundle pier.

compound rafter One of a pair of two rafters,
one spaced above the other; the one below is
usually called the secondary rafter.

compound shake Wood shakes, 2 found in
combination.

compound vault One whose construction
appears to depend upon a pendant placed on
each side, and within the walls that carry the
main vault.

compound wall A wall which is constructed
of more than one material; not of homogeneous
construction.

COMPR l.On drawings, abbr. for "composi-
tion roof." 2. On drawings, abbr. for "compress."
3. On drawings, abbr. for "compressor."

compregnated wood, resin-treated wood

Wood impregnated with a thermosetting resin,
then subjected to heat and pressure to provide
both resin curing and compression.

comprehensive general liability insurance
A broad form of liability insurance covering
claims for bodily injury and property damage
which combines under one policy coverage for
all liability exposures (except those specifically
excluded) on a blanket basis and automatically
covers new and unknown hazards that may
develop; automatically includes contractual lia-
bility coverage for certain types of contracts.

comprehensive planning See community
planning.

comprehensive services Professional ser-
vices performed by the architect in addition to
the basic services, in such related areas as proj-
ect analysis, programming, land use studies,
feasibility investigations, financing, construc-
tion management, and special consulting ser-
vices.

compressed cork Same as corkboard.

compressed fiberboard See hardboard.

compressed straw slab See strawboard.

compressed wood, densified wood Wood
which has been impregnated with resin and sub-
jected to a high pressure to increase its density
and strength.

compressibility The relative resistance (e.g.,
of a soil mass) to a change in volume upon being
subjected to a compressive stress.

compression 1 . The state of being compressed,
or being shortened by a force. 2. The change in
length produced in a test specimen by a com-
pressive load.

compression bearing joint A joint, between
two structural members in compression, that
transmits the compressive stress from one mem-
ber to the other.

compression coupling A coupling used to
connect sections of hubless pipe (i.e., pipe with-
out a hub), acid-resistant cast-iron pipe, or glass-
pipe; consists of an inner elastomeric gasket and
an outer metallic sleeve, with an integral bolt
used to tighten and compress the seal.

compression failure 1. Mechanical failure
in wood as a result of compression along the
direction of the grain, due either to direct-end

240

compressor-type liquid chiller

Hu bless
pipe

-_a

]]]]

Stainless steel ,

shield

Huhless
pipe

33313]]

Gasket

>. Slain less steel
p etaining clamp

compression coupling

compression or to bending. 2. See primary com-
pression failure.
compression faucet A faucet in which water
flow is shut off by a flat disk that is screwed down
onto its seat.

STEM
PACKING NUT

SEAT WASHER

PACKING

STEM WASHER

THREADED SPINDLE
VALVE SEAT

FLOW OPENING

compression faucet

compression flange The widened portion of a
beam or girder, such as the horizontal portion of
the cross section of a simple-span T-beam, which
is shortened by bending under a normal load.

compression gasket A gasket designed for
use under compression.

compression glazing The setting of a pane of
glass in an opening using a glazing gasket, 2 to
hold the glass in place.

compression joint l.Any joint formed by a
fitting designed to join piping or tubing by
means of pressure. 2. A joint having cup-shaped
threaded nuts which, when tightened, compress
tapered sleeves so they form a tight joint along
the periphery of the tubing they connect.

compression loading A reduction in the
thickness of an elastomeric element along the
line of an externally applied force.

compression member Any member in which
the primary stress is longitudinal compression.

compression molding A technique of ther-
moset molding; a molding compound is placed
in a polished steel mold, and then heat and pres-
sure are applied.

compression reinforcement Structural rein-
forcement which is designed to carry compressive
stresses.

compression seal A material which provides
a seal as a result of pressure between the faces of
a joint.

compression set The permanent deformation
of an elastomeric sealant, compressed so far that
its internal structure is partially or completely
destroyed and it no longer will assume its previ-
ous shape.

compression test On a specimen of mortar or
concrete, a test to determine its compressive
strength; in the US, unless otherwise specified,
mortar test specimens are 2-in. cubes, and con-
crete test specimens are cylinders 6 in. in diame-
ter and 1 2 in. high.

compression valve A valve in which water
flow is shut off by a flat disk that is screwed down
onto its seat.

compression wood Abnormal wood formed
on the underside of branches and leaning trunks
of softwoods; usually lower in strength; has
unusual shrinkage characteristics.

compressive strain The strain caused by a
compressive load.

compressive strength The maximum com-
pressive stress which a material is capable of sus-
taining.

compressive stress 1. The stress which resists
the shortening effect of an external compressive
force. 2. For a test specimen: the compressive
load per unit area of original cross section car-
ried by the test specimen at any time during a
compression test.

compressor A machine for compressing air or
other gases which is a basic component in some
refrigeration systems; draws vaporized refrigerant
from the evaporator at a relatively low pres-
sure, compresses it, and then discharges it to a
condenser.

compressor-type liquid chiller Equipment
utilizing a compressor, condensor, evaporator,
controls, and accessories to cool water or other
secondary liquid.

241

compulsory acquisition

compulsory acquisition Same as eminent
domain.

computer-aided design (CAD) The analy-
sis and/or design, and/or modeling, and/or simu-
lation, and/or layout of building design with the
aid of a computer.

CONC l.On drawings, abbr. for concrete.
2. On drawings, abbr. for "concentric."

concameration l.An arch or vault. 2. An
apartment; a chamber.

concave joint A recessed masonry joint,
formed in mortar by the use of a curved steel
jointing tool; because of its curved shape it is
very effective in resisting rain penetration; used
in areas subjected to heavy rains and high winds.

concave joint

concealed Said of materials, components, con-
trols, etc., that are rendered inaccessible by the
finish or structure of a building.

concealed arch A camber arch having a
slight convex rise so that when it is under a load,
it has no sag.

concealed cleat A metal strap or cleat used to
anchor sheet-metal roofing or flashing to the
roof sheathing (or blocking); used to conceal the
anchor under the sheet metal.

concealed downspout A downspout (down-
pipe) that is covered or recessed, rather than
surface -mounted.

concealed flashing On a roof, flashing which
is entirely concealed by shingles.

FLASHING

concealed cleat

concealed closer See overhead concealed
closer.

concealed flashing

concealed-grid ceiling system A grid support
system that is not visible from below; used in cer-
tain types of suspended acoustical tile ceilings.

concealed gutter A gutter built into the eaves
of a roof, usually metal-lined.

concealed heating A system (such as a panel
heating system) that employs heating elements
which are concealed from view or are blended
into the architectural features of a room.

concealed nailing l.See blind nailing. 2. In

roofing, see nailing.

concealed piping Piping which usually requires
the removal of permanent construction to gain
access to it.

concealed routing Routing at the bottom of a
cabinet door or drawer to provide a means of
opening and closing without pulls.

concealed suspension system A system for
suspending an acoustical ceiling in which no
suspension members are visible in the room.

concealed valley A type of valley on a roof; the
shingles or slates are laid to the intersecting roof
surfaces, covering the metal lining of the valley.

concentrated load A load acting on a very
small area of a structure, as differentiated from a
distributed load.

242

concrete-encased electrode

concentric Having a common center.

concentric castles Two fortified castles, one
within the other, having concentric lines of
defense; the inner curtain wall rises higher than
the outer, thus providing lines of fire at an
enemy at two different levels.

concentricity Conformance to a common
center as, for example, the inner and outer walls
of round tube.

concentric load See centric load.

concentric tendon One of a number of ten-
dons which follow a line through the center of
gravity of a prestressed concrete member.

concept plan A plan, 1 illustrating the assess-
ment and possible suitable development of a site.

conch The domed roof of a semicircular apse.

concha l.The semidome vaulting of an apse;
also called a conch. 2. In Spanish architecture and
its derivatives, a decorative element in the form of
the interior of a sea scallop; see shell-headed.

concordant tendon In a statically indetermi-
nate structure, a tendon that is coincident with
the pressure line produced by the tendon.

concourse l.An open space where several
roads or paths meet. 2. An open space for
accommodating large crowds in a building, as in
a railway terminal.

concrete A composite stonelike material
formed by mixing an aggregate (such as stones of
irregular shape or crushed rock) with cement
(which acts as the binding material) and water,
then allowing the mixture to dry and harden;
Portland cement, now used in making concrete,
was not developed until the 19th century. Also
see average concrete, cyclopean concrete, poured
concrete, reinforced concrete.

concrete admixture See admixture.

concrete aggregate See aggregate.

concrete agitation See concrete vibration.

concrete anchor See anchor.

concrete block A hollow or solid concrete
masonry unit consisting of portland cement and
suitable aggregates combined with water. Lime,
fly ash, air-entraining agents, or other admix-
tures may be included. Sometimes incorrectly
called cement block.

concrete bond, concrete bond plaster
See bond plaster.

concrete block

concrete border l.On a theater stage, the
lighting batten nearest the proscenium. 2. A cur-
tain concealing the lighting batten nearest the
proscenium.

concrete boxing Pans, 5 of molded fiberglass
or plywood, used to give the desired shape to
poured concrete.

concrete breaker A compressed-air tool for
breaking up concrete.

concrete brick A solid concrete masonry unit,
rectangular in shape, usually not larger than 4
in. by 4 in. by 12 in. (10 cm by 10 cm by 30 cm);
made from portland cement and suitable aggre-
gates; may include other materials.

concrete cart See buggy.

concrete cancer Descriptive of condition of a
spalling and/or fracturing of concrete as a result
of the use of unsuitable ingredients in the con-
crete mix; eventually leads to corrosion.

concrete collar, doughnut A collar of rein-
forced concrete which is placed around an exist-
ing column so that it can be jacked up; the
shrinkage of the concrete causes it to grip the
column firmly.

concrete compliance conformity The agree-
ment between the properties of concrete that
were specified and those that were furnished by
the supplier.

concrete column A column, 1 made of either
reinforced or unreinforced concrete.

concrete curing blanket See curing blanket.

concrete curing compound A chemical
compound which is applied to a concrete surface
to prevent the loss of moisture during early
stages of cement hydration.

concrete-encased beam A steel beam that is
totally encased in concrete which is cast inte-
grally with the concrete slab.

concrete-encased electrode See encased
electrode.

243

concrete finishing machine

concrete finishing machine l.A machine
mounted on flanged wheels which rides on forms
or specially set tracks, used to finish concrete
surfaces such as those of pavements. 2. A
portable power-driven machine for floating and
finishing concrete floors and slabs.

concrete flatwork Finishing operations on
concrete floors and slabs.

concrete floor hardener A liquid or dry mix-
ture of chemicals, minerals, metals, and/or other
synthetic materials which produces a dense wear-
resistant and/or nonslip and/or colored surface on
concrete floors.

concrete footing See footing.

concrete form See form.

concrete form coating See form coating.

concrete formwork See formwork.

concrete frame construction A structure
consisting of concrete beams, girders, and columns
which are rigidly joined.

concrete grout Concrete that contains no
coarse aggregate.

concrete gun A spray gun used in applying
freshly mixed concrete; compressed air forces
the concrete along a flexible hose and through a
nozzle.

concrete hardener An admixture that signif-
icantly alters the rate of hydration of concrete so
as to increase its strength.

concrete insert A plastic, wood fiber, or metal
(often lead) plug, either built in a wall or ceiling
or inserted by drilling; used as an anchor or sup-
port to hold attached loads.

concrete insert

concrete masonry 1. Construction consist-
ing of concrete masonry units laid up in mortar
or grout. 2. Poured concrete construction.

concrete masonry unit A block or brick cast
of portland cement and suitable aggregate, with

or without admixtures, and intended for laying
up with other units as in normal stone masonry
construction. Also see A-block, breeze block,
cinder block, concrete block, concrete brick, etc.

concrete mixer, cement mixer A machine
that mixes concrete ingredients by means of pad-
dles or a rotating drum. Raw materials usually are
introduced into the mixing drum through its
open end and discharged by tilting the mixing
drum to allow the concrete to pour out.

concrete nail A hardened-steel nail having a
flat countersunk head and a diamond point; used
for nailing to concrete or masonry.

concrete nail

concrete paint See cement paint.

concrete pile A concrete pile which is driven
into the ground or otherwise placed; may be a
precast pile, reinforced pile, or prestressed con-
crete pile.

concrete pipe A porous pipe, fabricated of
concrete, used primarily for subsoil drainage.

concrete planer A self-propelled machine
equipped with a series of rotating blades (or
drums) for smoothing and leveling in refinishing
old concrete pavement.

concrete plank A precast, prestressed, hol-
low-core concrete plank, usually relatively light-
weight; used for floor and roof decking; may
carry a structural topping.

concrete posttensioning See posttensioning.

concrete pump A machine that mixes con-
crete ingredients and then moves the concrete
mixture through a hose to the point of place-
ment. Also see pneumatic placement.

concrete reinforcement See reinforcement.

concrete retarder A material added to con-
crete to increase its setting time by decreasing
the rate at which hydration takes place.

concrete saw A power-operated saw used in
grooving uncured concrete (to prevent crack-
ing) or in cutting hard concrete slabs.

concrete slab A flat, rectangular, reinforced
concrete structural member; especially used for
floors, roofs, pads, etc.

244

conductive flooring

concrete vibrating machine A machine
which compacts a layer of freshly mixed con-
crete by vibration.

concrete vibration Energetic agitation of
freshly mixed concrete during placement by
mechanical oscillation devices at moderately
high frequency to assist in its consolidation.

concrete vibrator A device for agitating
freshly mixed concrete during placement by
mechanical oscillation at a moderately high fre-
quency to assist in consolidation.

concreting paper A building paper.

concurrent loads Two or more elements of
dead (or live) loads that, for purposes of design,
are considered to act simultaneously.

condemnation 1 . The process by which prop-
erty of a private owner is taken for public use,
without his consent, but upon the award and
payment of just compensation, being in the
nature of a forced sale. 2. A legal declaration that
a piece of property or a building is unfit for use.

condensate The liquid formed by the conden-
sation of a vapor; in steam heating, water is con-
densed from steam; in air conditioning, water is
extracted from air.

condensate unit A packaged unit comprising
a tank and pump which store and transfer con-
densed steam to a remote location.

condensation 1. In a refrigeration system, the
process of changing the refrigerant into liquid
by the extraction of heat. 2. See surface conden-
sation.

condensation gutter, condensation chan-
nel, condensation groove, condensation
trough A trough-like depression in the top of
the interior sill of a glazed opening, to receive
and carry off moisture forming on the indoor
face of the glass.

condenser A heat-exchange device in a refrig-
eration system; consists of a vessel or arrangement
of pipes or tubing in which refrigerant vapor is
liquefied (condensed) by the removal of heat.

condenser tube Metal tubing manufactured to
special requirements as to tolerances, finish, and
temper; used in water cooling in a heat exchanger.

condensing unit In a refrigeration system, a sin-
gle compact unit consisting of one or more power-
driven compressors, condensers, liquid receivers
(when required), and control accessories.

condition appraisal An estimate of the value
of an asset based largely on an inspection of its
current physical condition.

condition-based maintenance The condi-
tion monitoring of a building, used to predict fail-
ure of an item or element in the building and then
take appropriate action to avoid such failure.

conditioned air Said of air within a building if
it has been heated, cooled, humidified, and/or
dehumidified.

condition monitoring The measurement of
various parameters (such as vibration, bearing
temperature, oil pressure, and performance)
related to the mechanical condition of machin-
ery; this information is used to predict whether a
breakdown is apt occur in the very near future.

conditions of acceptance Criteria establishing
the limits within which the measured or observed
characteristics of a test specimen must fall in order
for it to comply with stated requirements.

conditions of the bid Conditions set forth in
the instructions to bidders, the notice to bidders
or advertisement for bids, the invitation to bid-
ders, or other similar documents prescribing the
conditions under which bids are to be prepared,
executed, submitted, received, and accepted.

conditions of the contract Those portions
of the contract documents which define, set
forth, or relate to: contract terminology; the
rights and responsibilities of the contracting par-
ties and of others involved in the work, 1 ;
requirements for safety and for compliance with
laws and regulations; general procedures for the
orderly prosecution and management of the
work; payments to the contractor; and similar
provisions of a general, nontechnical nature.

conditory A repository for storing things, esp.
an underground vault for the dead.

condominium A form of real estate owner-
ship of a multifamily residential dwelling. Each
occupant has 100% ownership of his own apart-
ment and partial ownership of common ele-
ments such as hallways, elevators, plumbing, etc.
Also see cooperative.

conductance See thermal conductance.

conduction See thermal conduction.

conductive flooring Flooring which has been
designed to eliminate or prevent electrostatic
buildup and electrostatic or mechanical sparking.

245

conductive loss

conductive loss The net decrease in heat
within a space as a result of losses to the exterior
and/or heat losses caused by exfiltration.

conductive rubber A rubber which has been
mixed with carbon black in fabrication; has suf-
ficient electrical conductivity to prevent elec-
trostatic buildup.

conductivity See thermal conductivity, elec-
trical conductivity.

conductor 1. A wire, cable, or device offering
low resistance to the flow of electric current. 2.
A material that transmits heat readily. 3. A
downspout. 4. Any vertical pipe which conveys
rainwater, including one within a building.

conductor head See leader head.

conductor shielding A metallic sheath which
surrounds an electric conductor.

conduit 1. A tube or pipe used to protect elec-
tric wiring. 2. A tube or pipe used for conveying
fluid. 3. Any channel intended for the con-
veyance of water, whether open or closed.

conduit body According to the NEC, a sepa-
rate portion of an electrical conduit or tubing
system that provides access through one or more
removable covers to the interior of the system at
a junction of two or more sections of the system
or at a terminal point of the system.

conduit box See junction box.

conduit fitting 1 . An accessory for a conduit, 1
system, such as a bushing or an access fitting. 2.
In an electrical conduit system, an accessory
such as an access fitting or bushing.

conduit hanger See hanger, 1.

cone bolt See cone-nut tie.

cone-cut veneer Wood veneer that has been
cut in a manner similar to the sharpening of a
pencil, to obtain circular sheets of highly figured
veneer.

cone-drum cyclorama See rolling cyclo-
rama.

conehead rivet A rivet which has a head
shaped like a truncated cylindrical cone.

cone-nut tie, cone bolt A type of tie rod
used in a concrete form for a wall; has a cone at
both ends; also acts as a spreader.

CLAMP

OUTER
ROD

JL -Ar J -

cone-nut tie

cone of depression A conically shaped
depression in the soil around a point where an
underground pump is located.

cone tile, cone hip tile See bonnet hip tile.

confession, confessio 1. The tomb of a mar-
tyr or confessor; if an altar was erected over the
grave, the name was also extended to the altar
and to the subterranean chamber in which it
stood; in later times a basilica was sometimes
erected over the chamber and the entire build-
ing was known as a confession. 2. The space
immediately below, or in front of, the primary
altar of a church.

confessional A small booth furnished with a
seat for a priest and with a window, screen, or
aperture so that the penitent, who is outside, may
whisper in the priest's ear without being seen.

conehead rivet

confessional

246

connector

configurated glass, figured glass Glass
having an irregular surface in a pattern that has
been rolled or formed during fabrication; used to
obscure vision or to diffuse light.

configuration The spatial arrangement of
wood particles, chips, flakes, or fibers used in
particleboard, fiberboard, etc.

confined concrete A concrete which has
closely-spaced special transverse reinforcement
which restrains the concrete in directions per-
pendicular to the applied stress.

conflagration hazard The risk involved in
the spread of fire by exterior exposure to and
from adjoining structures or buildings.

confluent vent A vent serving more than one
fixture vent or stack vent.

conge 1. See apophyge. 2. A quarter-round con-
cave molding, tangent to a vertical surface and
succeeded by a fillet parallel to that surface. 3. In
ceramic tile work, a sanitary base or sanitary shoe.

conge, 1

congelated Same as frosted, 1.
conglomerate Rock consisting of rounded

pebbles which are cemented together with a

finer material.

congregate residence A building (or portion
thereof) containing facilities for living, sanita-
tion, and sleeping as required by the applicable
building code; may include facilities for cooking
and/or eating for occupancy other than by a
family. This classification includes, for exam-
ple, convents, dormitories, fraternity or sorority
houses, and shelters.

conical roll See batten roll.

conical roof A roof in the shape of an inverted
cone, usually atop a cylindrical tower; also called
a candle-snuffer roof, or witch's cap.

conical vault A vault having a cross section in
the form of a circular arc, which is larger at one
end than the other.

conical vau

alt

conifer A cone-bearing tree or shrub of the
gymnospermous order; a softwood which includes
cypress, firs, pines, and spruce.

conisterium In ancient Greece and Rome, a
room appended to a gymnasium or palaestra in
which wrestlers were sprinkled with sand or dust
after having been anointed with oil.

connected barn See continuous house.

connected load The electric load (in watts)
on an electric system if all apparatus and equip-
ment connected to the system are energized
simultaneously.

Connecticut barn Same as Yankee barn.

connecting angle An angle section used to
connect two structural members.

connecting block A plastic block containing
metal wiring terminals; used to establish electri-
cal connections.

connection In steel construction, a combina-
tion of joints capable of transmitting forces
between two or more members.

connector 1. In an electric circuit, a device for
joining two or more conductors, by a low-resis-
tance path, without the use of a permanent
splice. 2. A mechanical device for fastening

2 y;

connector plate

together two or more pieces, members, or parts,
including anchors, fasteners, or wall ties.

connector plate In a truss, a prepunched
toothed metal connector located at a joint or
splice of a truss; designed to sustain the forces
that occur at such a location.

consent of surety 1. Written consent of the
surety on a performance bond and/or labor and
material payment bond to such contract changes
as change orders or reductions in the contrac-
tor's retainage, or to final payment, or to waiving
notification of contract changes. 2. Written
consent of the surety, to an extension of time in
a bid bond.

conservation The overseeing and mainte-
nance of a building to prevent or arrest its decay
or destruction, usually by applying a variety of
measures. See building conservation and build-
ing preservation.

conservatory l.A school for the teaching of
music, drama, or other fine arts. 2. A structure
chiefly used for growing flowers, plants, and out-
of-season fruits and vegetables under protected
conditions; it is attached to a dwelling, in con-
trast to a greenhouse which serves the same pur-
pose but is usually a separate structure in a
garden or field. Also see orangery, greenhouse,
and hothouse.

consideration In a building contract, the com-
pensation that shall be paid by one party to
another party in return for products and/or ser-
vices rendered.

consistency l.The degree of firmness, or the
relative ability of freshly mixed concrete, grout,
or mortar to flow; usually measured by the slump
test for concrete, and by the flow test for mortar,
plaster, cement paste, or grout. Also see viscos-
ity. 2. The property of a cohesive soil that
describes its physical state.

consistency index Same as relative consistency.

consistency limits Same as Atterberg limits.

consistometer An apparatus for measuring the
consistency of grouts, cement pastes, mortars, or
concrete.

consistory A chamber used for a church court.

console l.A decorative bracket in the form of a
vertical scroll, projecting from a wall to support a
cornice, a door or window head, a piece of sculp-
ture, etc.; an ancon. 2. The cabinet from which

console, 1

an organ is played, including the keyboards, ped-
als, stops, etc. 3. A panel control desk or cabinet
containing dials, meters, switches, and other
apparatus for controlling mechanical, hydro-
mechanical, or electrical equipment.
console bracket A console, 1.

console lift A section of the floor area of a the-
ater or auditorium that can be raised or lowered.

console table A table attached to a wall and
supported on consoles.

consolidation l.The compaction of freshly
placed concrete or mortar, usually by vibration,
centrifugation, or tamping, to mold it within
forms and around embedded parts and reinforce-
ment and to eliminate voids other than entrained
air. Also see compaction. 2. The process whereby
soil particles are packed more closely by the appli-
cation of continued pressure.

consolidation grouting l.The injection of
fluid grouting, usually portland cement and
sand, into a compressible soil mass to displace it
and form a structure for support. 2. Same as area
grouting.

consolidation settlement Of loaded clay, a
settlement which takes place over a period of
years.

con spec Abbr. for "construction specification."

CONST On drawings, abbr. for construction.

constant-voltage transformer A special
transformer which is designed to provide constant

248

construction management

voltage at its output, independent of voltage vari-
ations in the line to which its input is connected.

constant volume system An air-condition-
ing system which supplies air at a fixed volume
per unit time; the temperature of the supplied air
is used to regulate the temperature of the air-
conditioned space if there are variations in the
load on the system.

constant-wattage ballast A ballast used with
a high-intensity discharge lamp to minimize the
effects of voltage variations and to provide a
high power-factor.

constratum In ancient Rome, a flooring con-
structed of planks.

construction 1. All the on-site work done
in building or altering structures, from land
clearance through completion, including exca-
vation, erection, and the assembly and instal-
lation of components and equipment. 2. A
structure. 3. The manner in which something is
built.

construction administrator An individual
who oversees the responsibilities of a contract
for construction. These responsibilities include
reviewing and certifying the amount due to the
contractor, preparing change orders, and con-
ducting site inspections to determine dates of
substantial completion and final completion.
Compare with construction manager.

construction bolt Any one of a number of
common steel bolts, used during construction as
a temporary fastening device, such as a bolt to
hold forms together.

construction bond A completion bond.

construction budget 1. The sum established
by the owner as available for construction of the
project. 2. The stipulated highest acceptable
bid price or, in the case of a project involving
multiple construction contracts, the stipulated
aggregate total of the highest acceptable bid
prices.

construction class A classification based on
the fire-resistance ratings of the construction of
a building or its parts.

construction close-out log A record of final
submissions on a construction job, including
warranties, operations, and maintenance. Usu-
ally compiled and completed near the end of
construction.

construction contract See contract for con-
struction.

construction contract administrator See
construction administrator.

construction cost The cost of all the construc-
tion portions of a project, generally based upon
the sum of the construction contract(s) and other
direct construction costs; does not include the
compensation paid to the architect and consul-
tants, the cost of the land, right-of-way, or other
costs which are defined in the contract docu-
ments as being the responsibility of the owner.

construction documents The working draw-
ings and specifications.

construction documents phase The
third phase of the architect's basic services. In
this phase the architect prepares from the
approved design development documents, for
approval by the owner, the working drawings
and specifications and the necessary bidding
information. In this phase the architect also
assists the owner in the preparation of bidding
forms, the conditions of the contract, and the
form of agreement between the owner and the
contractor.

construction drawings The portion of the
contract documents that are graphic representa-
tions of the work to be done in the construction
of a building.

construction equipment All machinery,
derricks, hoists, ladders, materials-handling
equipment, platforms, runways, safeguards and
protective devices, and scaffolds, as well as other
equipment, used in construction operations.

construction inspector See project represen-
tative.

construction joint 1. A joint where two suc-
cessive placements of concrete meet. 2. A sepa-
ration provided in a building which allows its
component parts to move with respect to each
other. The cause of such movement may be ther-
mal, seismic, or wind loading.

construction loads The loads, 1 during con-
struction, to which a structure is subjected.

construction loan A loan to a builder for a
short term, financing construction prior to per-
manent financing.

construction management The special man-
agement services performed by the architect or

249

construction manager

others during the construction phase of the proj-
ect, under separate or special agreement with
the owner. This is not part of the architect's
basic services, but is an additional service some-
times included in comprehensive services.

construction manager 1. A person who is
appointed by the owner to work as the owner's
agent in the construction work, preparing bid-
ding documents and contract documents,
arranging construction contracts, and manag-
ing the contractors so that all work on the proj-
ect is completed on time and within budget, in
accordance with contractual agreements. 2.
The person who has been designated by the
owner to provide special management services
during the construction phase of a building
project.

construction phase — administration of
the construction contract The fifth and
final phase of the architect's basic services,
which includes the architect's general adminis-
tration of the construction contract(s). Also see
contract administration.

Construction Specifications Canada (CSC)
A nonprofit organization devoted to the stan-
dardization of construction documents in
Canada; used in both the private and public sec-
tors. The MasterFormat has been adopted as the
basis for a numbering and titling system for the
Canadian National Master Specification (NMS).
Head office: 120 Carlton St., Toronto ON M5A
4K2, Canada.

Construction Specifications Institute (CSI)
A non-profit technical organization serving con-
struction specifiers and related building profes-
sionals in the US. CSI publishes MasterFormat
jointly with the Construction Specifications
Canada. Head office: 99 Canal Center Plaza,
Alexandria, VA 22314.

construction survey See engineering survey.

construction wrench A wrench having an
open end for turning nuts and bolts; the other
end tapers to a blunt point which is used to align
mating holes in steel construction.

constructive eviction The rendering of
leased premises uninhabitable because of the
landlord's improper acts of commission or omis-
sion; gives rise to the same legal consequences as
an unlawful eviction. See eviction.

Constructivism A movement which origi-
nated in Moscow after 1917, primarily in sculp-
ture, but with broad applications to architecture.
The expression of construction was to be the
basis for all building design, with emphasis on
functional machine parts. Tatlin's project of a
monument to the Third International in
Moscow (1920) is the most famous example.

Constructivism: Tatlin's project

constructor One who is in the business of con-
structing elements of the built environment, act-
ing under the terms of a construction contract.

consulate A building or place where a consul
conducts official business.

consulting engineer An engineer, usually
employed by the owner or architect to perform
specific tasks of engineering design for a portion
of the construction contract.

consultant An individual or organization
engaged by the owner or the architect to render
professional consulting services complementing
or supplementing the architect's services.

CONT On drawings, abbr. for "continue."

contact A part which is an electric conductor
and which provides a low-resistance path for
current flow upon mating with another conduct-
ing part with which it is designed to operate.

250

continuous beam

contact adhesive, contact-bond adhesive,
dry-bond adhesive An adhesive that is
apparently dry to the touch and adheres instan-
taneously upon contact.

contact-bond adhesive See contact adhe-
sive.

contact ceiling A ceiling that is secured
directly to the construction above, without the
use of furring channels.

contactor Any device for repeatedly opening
and closing an electric power circuit.

contact pressure Pressure, produced by the
weight of a footing and all the forces acting
on it, which acts at and perpendicular to the
contact area between the footing and the soil.

contact pressure adhesive An adhesive

that is permanently tacky at room temperature
and adheres to many types of surfaces upon con-
tact, requiring little pressure in application.

contact splice A type of connection between
reinforcing bars in reinforced concrete; the bars
are lapped and are in direct contact.

container packer A refuse compactor that
compresses refuse within a steel container. The
container is latched to the compactor by special
locking devices.

containerized plant In landscape architec-
ture, a growing plant, together with its root sys-
tem, that is sold intact in a container.

containment grouting Same as perimeter
grouting.

contamination The introduction of sewage,
wastes, and/or chemicals (or other material) into
a potable water supply that render it unfit for its
intended purpose.

Contemporary style An imprecise term
applied to any of a number of architectural
modes popular from about the 1940s through
the 1970s and beyond, sometimes included
under the term modern architecture; often char-
acterized by widely overhanging eaves,
exposed roof beams, and front-facing gables
with heavy piers that support the gables; often,
a balcony with an overhanging sunscreen, roof
decks, and a patio that may serve as an exten-
sion of the living area; another type has a
facade and flat roof resembling that of the
International style.

contents hazard classification The classifi-
cation of the potential danger of building con-
tents as ordinary, high, or low.

contextualism The "fitting-in" of a building
with surrounding buildings so that it is in har-
mony with them, especially in terms of scale,
form, mass, and color.

contignation A framework, as of beams.

continental cabin A one-and-one-half-story
log house attributed to German-speaking immi-
grants to colonial America; usually consisted of
a large room at the front of the house, a bedroom
behind it, and a long narrow kitchen along one
side. A sizable stove in the kitchen was used
both for cooking and for heating the adjacent
large room.

continental seating A seating arrangement
in an auditorium in which the rows of seats are
unbroken by aisles or crossovers; access to the
rows is from an aisle at the end of the rows or
from doors along the sidewalls.

contingency An amount of money, included
in the budget for building construction, that is
uncommitted for any specific purpose. This
amount is intended to cover the cost of unfore-
seen factors related to the construction which
are not specifically addressed in the budget.

contingency allowance A sum designated to
cover unpredictable or unforeseen items of work,
1 or changes subsequently required by the owner.

contingent agreement Any agreement under
which the rights or obligations of a party are sub-
ject to the happening of a stated contingency, e.g.,
an agreement between an owner and an architect
in which part or all of the architect's compensa-
tion is contingent upon the owner's obtaining
funds for the project (such as by successful refer-
endum, sale of bonds, or other financing), or upon
some other specially prescribed condition.

continuous accessible path of travel See
accessible route.

continuous acoustical ceiling A suspended
acoustical ceiling in which the top of a partition
extends only to the lower surface of the ceiling.

continuous beam A beam which extends
over three or more supports, joined together so
that, for a given load on one span, the effect on
the other spans can be calculated.

251

continuous block core

continuous block core, edge-glued core,
stave core A solid core consisting of blocks
of wood which are bonded together and sanded
to a smooth uniform thickness; used in wood
doors, panels, etc.

continuous footing A combined footing, of

prismatic or truncated shape, which supports
two or more columns in a row.

continuous foundation A foundation which

supports a number of independent loads.

continuous girder A girder with more than
two supports.

continuous grading A particle-size distribu-
tion for material such as an aggregate in which
all intermediate-size fractions are present, as
opposed to gap grading.

continuous handrail Handrail for a geomet-
rical stair.

continuous header A top plate consisting of
timbers on end which are joined (along their
lengths and at corners) to form a continuous,
rigid framework around a structure, sufficiently
strong to act as a lintel over wall openings.

CONTINUOUS
HEADER

CORNER POST

continuous header

continuous hinge, piano hinge A hinge
having the same length as the moving part to
which it is applied.

continuous house A house that is connected
to several other ancillary facilities such as a barn,
privy, shed, and/or stable; advantageous in areas
having a harsh winter climate because this
arrangement permits the residents to use these
dependencies without going outdoors. Compare
with telescope house.

-o
-

continuous hinge

continuous impost In Gothic architecture,
the moldings of an arch when carried down to
the floor without interruption or anything to
mark the impost point.

continuous impost

continuous kiln See progressive kiln.

continuous load Said of an electrical load in
which the maximum current is expected to con-
tinue for at least 3 hours at a time.

continuously reinforced pavement A

pavement having no transverse joints, except
tied construction joints which are placed
between successive days' concreting, with suffi-
cient longitudinal reinforcement, adequately
lapped to develop tensile continuity.

continuous mixer A mixer for concrete or
mortar into which ingredients are fed without
stopping and from which the mix is discharged
in a continuous stream, in contrast to the peri-
odic discharge of a batch mixer.

continuous moving formwork See slip form.

continuous-pressure electric elevator An
electric elevator operated by means of push

252

contract award

buttons in the elevator car and at landings,
requiring that a button be held manually to keep
the car in motion.

continuous ridge vent A screened, water-
shielded opening for a ventilator that runs con-
tinuously along the ridge of a gable roof

continuous rating The maximum constant
load that can be carried by a piece of electric
equipment without exceeding a designated tem-
perature rise.

continuous slab A slab which extends as a unit
over three or more supports in a given direction.

continuous span A span which is formed of a
series of consecutive spans (over three or more
supports) that are continuously or rigidly con-
nected so that bending moment may be trans-
mitted from one span to the adjacent ones.

continuous string A string for a geometrical
stair.

continuous truss A truss that extends over
three or more supports.

continuous vent A vertical vent that is a con-
tinuation of a drain, a soil pipe, or a waste pipe
to which the vent connects.

Continuous vent for
lavatories and
similar fixtures

Loop vent

continuous vent

continuous waste A drain from two or more
plumbing fixtures connected to a single trap.

continuous waste-and-vent A waste pipe
and a vent pipe which are in a straight line, the
latter being a continuation of the former.

contour basin A level basin on a sloping site
to catch rainfall.

contour curtain A theater stage curtain which
can be raised in separate folds by individual lines
which are attached to its component sections,
thereby controlling its shape or contour.

contour interval The vertical distance between
adjacent contour lines.

contour line A line on a map or drawing repre-
senting points of equal elevation on the ground.

continuous waste

contour lines

contour map A topographic map which por-
trays relief by the use of contour lines which con-
nect points of equal elevation; the closer the
spacing of the lines, the greater the relative slope.

CONTR On drawings, abbr. for contractor.

contract A legally enforceable promise or
agreement between two or among several per-
sons. Also see agreement.

contract administration The duties and
responsibilities of the architect during the con-
struction phase.

contract award The notification by an owner
to a bidder that his offer, or a negotiated pro-
posal, has been accepted. This award establishes
a legal obligation between the parties.

253

contract bond

contract bond See completion bond.

contract carpet A carpet, often heavy-duty,
that is purchased in bulk for non-domestic use.

contract date Same as date of agreement.

contract documents Those documents that
comprise a contract, e.g., in a construction con-
tract, the owner-contractor agreement, condi-

contract documents

tions of the contract (general, supplementary,
and other conditions), plans and/or drawings,
specifications, all addenda, modifications, and
changes thereto, together with any other items
stipulated as being specifically included.

contract drawings The drawings that form a
part of the contract documents.

contract for construction An agreement
between the owner and contractor in which the
contractor agrees to construct the owner's build-
ing (or other described project) in accordance
with the contract documents and within a spec-
ified time, for a mutually-agreed upon consider-
ation to be paid by the owner.

contracting officer The person designated as
an official representative of the owner with spe-
cific authority to act in his behalf in connection
with a project.

contraction Of concrete, the sum of volume
changes occurring as the result of all processes
affecting the bulk volume of a mass of concrete.

contraction joint 1. An expansion joint, 1 . 2.
A joint between adjacent parts of a structure
which permits movement between them result-
ing from contraction.

contraction joint grouting The injection of
grout into a contraction joint.

contract limit A limit line or perimeter line
established on the drawings or elsewhere in the
contract documents defining the boundaries of
the site available to the contractor for construc-
tion purposes.

contract load The load specified in the contract
for the purchase of an elevator, or the load speci-
fied in the application for the building permit.

contract manager See contracting officer and
construction manager.

contract modification Additions to, dele-
tions from, or modifications of the work, 1 to be
done, after the construction agreement has been
signed.

contractor One who undertakes responsibility
for the performance of construction work, includ-
ing the provision of labor and materials, in accor-
dance with plans and specifications and under a
contract specifying cost and schedule for comple-
tion of the work; the person or organization
responsible for performing the work, 1 and identi-
fied as such in the owner-contractor agreement.

254

contributing chapel

contractor's affidavit A certified statement
of the contractor, properly notarized, relating to
payment of debts and claims, release of liens, or
similar matters requiring specific evidence for
the protection of the owner. Also see noncollu-
sion affidavit.

contractor's breakdown See schedule of
values.

contractor's estimate l.A forecast of con-
struction cost, as opposed to a firm proposal, pre-
pared by a contractor for a project or a portion
thereof. 2. A term sometimes used to denote a
contractor's application or request for a progress
payment. Also see application for payment.

contractor's liability insurance Insurance
purchased and maintained by the contractor to
protect him from specified claims which may
arise out of or result from his operations under
the contract, whether such operations be by
himself or by any subcontractor or by anyone
directly or indirectly employed by any of them,
or by anyone for whose acts any of them may be
liable.

contractor's option A provision of the con-
tract documents under which the contractor
may select certain specified materials, methods,
or systems at his own option, without change in
the contract sum.

contractor's proposal See bid.

contractor's qualification statement A

statement of the contractor's qualifications,
experience, financial condition, business his-
tory, and staff composition. This statement,
together with listed business and professional
references, is intended to provide evidence of
the contractor's ability to perform the work, 1
and to assume the responsibilities required by
the contract documents.

contract period See contract time.

contract speed The speed specified in the
contract for the purchase of an elevator, or the
speed specified in the application for the build-
ing permit.

contract sum The price stated in the owner-
contractor agreement, which is the total amount
payable by the owner to the contractor for the
performance of the work, 1 under the contract
documents; can be adjusted only by a change
order.

contract time The period of time stipulated in
the construction contract for the substantial
completion of the work.

contractual liability Liability assumed by a
party under a contract by express language,
implication, or operation of law; includes not
only the obligation of a party to perform in
accordance with the contract but also such other
obligations as may be assumed, e.g., those arising
from indemnification or "hold harmless" clauses.

contractura The tapering of a column from
bottom to top.

contraflexure point Same as point of inflec-
tion.

contramure Same as countermure.

contrasted arch An arch, such as an ogee arch,

containing a reverse curve.

contrast ratio The ratio of the reflectance of
a dry paint film over a black substrate having
5 percent reflectance or less, to the reflectance
of the same paint equivalently applied over a
substrate having an 80 percent reflectance.

contrast sensitivity The ability to detect the
presence of differences in luminance; the recip-
rocal of the contrast threshold.

contrast threshold l.The minimum percep-
tible contrast for a given state of adaptation of
the eye. 2. The luminance contrast which can
barely be detected by an observer.

contravallation In military architecture, a
series of redoubts and breastworks to guard
against sorties of an enemy garrison.

contrefort In Medieval architecture, a brick-
work revetment for ramparts on the side of a ter-
replein, or for counterscarps and gorges.

contre-imbrication An ornamental pattern
on a surface that forms overlapping elements
which are below the general plane of the surface.
This is in contrast to imbrication, in which the
overlapping elements are above the general
plane of the surface.

contrevents In French Vernacular architec-
ture, same as wood shutters.

contributing chapel In Spanish Colonial
architecture, a chapel usually having no perma-
nent padre to officiate at religious ceremonies,
relying instead on the part-time assistance of vis-
iting priests.

255

control

control Any device for regulating a system or
component during its normal (manual or auto-
matic) operation; it is responsive, during auto-
matic operation, to the property (such as pres-
sure or temperature) whose magnitude is to be
regulated.

control area A building (or portion thereof) in
which exempted quantities of hazardous materi-
als may be dispensed, handled, stored, or used.

control board, control desk, control panel
control rack One or more panels comprised
of an assembly of master switches, adjustable
controls, indicating dials or numerical readouts,
and the like, used to control and monitor the
state of a remotely operated system (e.g., a light-
ing system, sound system, or air conditioning
system) and equipment.

control desk A position in a library, public
lobby, hospital, etc., where activities may be
overseen or supervised.

control factor The ratio of the minimum com-
pressive strength of a material, such as concrete,
to the average compressive strength.

control gap Same as control joint.

control joint A groove which is formed, sawed,
or tooled in a concrete or masonry structure to
regulate the location and amount of cracking
and separation resulting from the dimensional
change of different parts of the structure, thereby
avoiding the development of high stresses.

control joint

control-joint grouting The injection of grout
into a control joint.

controlled construction The construction
of a building or structure, or of a part thereof, by
an architect and/or licensed professional engi-
neer in accordance with code requirements and
accepted engineering practice.

controlled fill Fill (intended as a bearing for a
structural load) which is placed in layers, com-
pacted, and tested to ensure that it meets speci-
fied compaction standards as determined by
laboratory tests on a series of soil samples from
the fill material.

controlled flow Said of a roof drainage system
that regulates the drainage of rainwater so that it
is essentially uniform.

controlled-flow roof drainage system A

roof drainage system that permits rainwater to
drain off a roof much more slowly than the rate
at which it accumulates; after the storm has
abated, the accumulation drains off at a con-
trolled rate.

controlled low-strength material A mate-
rial resulting in a compressive strength of no more
than 1200 pounds per square inch (8300 kPa).

controlled materials Materials that are certi-
fied by an appropriately accredited agency as
having met the accepted engineering standards
for good quality.

controller An electric device (or combination
of devices) designed to initiate one or more
functions of operation, such as starting, stop-
ping, reversing, and speed changing, of the appa-
ratus to which it is connected; operation may be
manual or automatic.

control room, console room A small room,
in or adjacent to an auditorium, having a view of
the stage, in which the lighting or sound-control
consoles are located.

control set-point In an automatic control sys-
tem, the point at which the value a control set-
ting must be pre-set in order to achieve a desired
value. For example, in an air-conditioning sys-
tem, the set-point is the value of temperature
that must be pre-set in order to establish the
desired temperature in the conditioned space.

control survey A survey, 1 that provides hori-
zontal and vertical positions of points to which
supplementary surveys are adjusted.

control valve Any valve used to regulate fluid
flow.

CONT W On drawings, abbr. for "continuous
window."

conv. Abbr. for convector.

convalescent home A medical-care institu-
tion providing services for patients recovering
from acute or postoperative conditions who do
not require the level of skilled services provided by
an extended-care facility or warrant custodial care
such as that normally rendered in nursing homes.

convection Heat transmission, either natural
or forced (by means of a fan), by currents of air

256

conveyance

resulting from differences in density due to tem-
perature differences in the heated space.

convection circulation In a hot-water heating
system, the movement of water through the pipes as
a result of gravity which causes the lighter, warm
water in the system to rise, and the cool water to fall.

convection current The transfer of heat that
results from the movement of air from one loca-
tion to another, usually as a result of a stream of
air produced by thermal convection caused by
differences in temperature.

convection heating Heating which results from
the movement of air (or any other gas or liquid),
carrying heat from the hotter to the cooler spaces.

convection loss Heat loss in a building resulting
from temperature differences in the heated space.

convective movement See natural convec-
tion.

convector A surface designed to transfer its
heat to a surrounding fluid largely or wholly by
convection; units for water or steam heating
usually are installed against the wall or in a
recess in the wall.

convector

convenience outlet A receptacle outlet which
is mounted on the wall of a room to supply elec-
tricity for lamps, appliances, etc.

convenience receptacle Same as receptacle.

convent 1. A religious community: friars, monks,
or nuns (now usually nuns). 2. A group of build-
ings occupied by such a community.

conventional design Design procedures using
stresses or moments which have been deter-
mined by widely accepted methods.

conventional door Any door (including a
kalamein door) except one of a special type,
such as a fire door, a sound-attenuating door, or
the like.

conventional sprinkler In a fire protection
system, a sprinkler providing a spherical water
distribution directed towards the floor and ceil-
ing; directs 40 to 60 percent of the total water
flow initially in a downward direction.

convention center An air-conditioned multi-
purpose facility generally used for meetings, con-
ventions, and the display of merchandise by a
wide variety of industrial groups, professional
groups, and trade organizations. The size of the
facility ranges from small to very large — some-
times over more than 2 million square feet
(approximately 18 hectares). The interior must
be flexible so that it can be divided into various-
sized spaces. Regardless of size, a convention cen-
ter requires meeting spaces, movable partitions to
subdivide these spaces, sanitary facilities, loading
docks, adequate heating, cooling, electrical and
communications equipment, and trained main-
tenance staff.

convento In Spanish architecture and its
derivatives, a convent or monastery usually con-
taining living quarters, workrooms, storerooms,
a balcony, and patio.

conversion l.See breaking down. 2. A

change in the use of a building to another use
which has different requirements according to
code (e.g., different exit, fire-resistance, light
and ventilation, loading, structural, or zoning
requirements).
conversion burner A burner, together with
its control unit, which is designed as a replace-
ment for an existing boiler or furnace.

conversion factor A quantity by which the
numerical value in one system of units must be
multiplied to arrive at the numerical value in
another system of units.

converted timber Timber sawn into lumber
or boards.

converter A device or machine used to change
alternating-current power to direct-current power
or vice versa.

conveyance 1 . The transfer of property from
one person to another. 2. The document or
instrument by which this transfer is effected.

257

conveying hose

conveying hose Same as delivery hose.

conveyor A motor-driven mechanism used for
the continuous transport of material, e.g., an
endless belt or series of rollers.

cooked glue Glue requiring heating before use.

cook house Same as outkitchen.

coolant See cooling medium.

cool cellar A cellar, 1 beneath a house, whose
temperature is low enough to store beverages,
dairy products, meat, and/or vegetables.

cooler 1. A thermally insulated enclosure, kept
at a reduced temperature by means of refrigera-
tion. 2. An air conditioner.

coolhouse A greenhouse which is maintained
at a cool temperature above freezing.

cooling capacity A measure of the amount of
heat that can be removed from a building (or
section thereof) in one hour.

cooling load The amount of heat that must be
removed from a building to maintain a comfort-
able temperature for its occupants.

cooling medium, coolant A fluid which
conducts heat from one or more heat sources
and transports it to a heat exchanger, where the
heat is removed and disposed of.

cooling pond See roof pond.

cooling range In a water-cooling device, the
difference between the average temperature of
the water entering the device and the average
temperature of the water leaving it.

cooling tower A structure, usually on the roof
of a building, over which water is circulated, so
as to cool it evaporatively by contact with air.

INTAKE

cooling tower of the induced-draft, propeller type

cooperative A form of real estate ownership of a
multi-unit housing structure by a non-profit cor-
poration which leases portions of the property to
its stockholders. The stockholders are part owners

of the corporation; they do not own their own
apartments. Periodic payments, usually monthly,
by stockholders are used to meet costs of owner-
ship, such as mortgage payments, property main-
tenance, taxes, and repairs. Such shareholding by
the tenant allows him to occupy a dwelling unit
while not possessing direct title to it.
cooperculum The cover of a baldachin or
ciborium.

coopered joint In a curved surface, a joint
similar in appearance to a joint in a barrel.

COORD On drawings, abbr. for "coordinate."

coordinator A device used on a pair of exit
doors to ensure that the inactive leaf is permit-
ted to close before the active leaf; required on a
door having an overlapping astragal.

cop Same as merlon.

cop. Abbr. for coping.

copal Resin of natural origin used in varnishes
to provide gloss and hardness.

copal varnish A high-gloss varnish made with
a drying oil, such as linseed oil, and copal.

cope l.To cut or shape the end of a molded
wood member so that it will cover and fit the
contour of an adjoining member. 2. To notch a
steel beam, channel, etc., so that another mem-
ber may be fitted against it. 3. A coping. 4. To
form a coping.

cope chisel Same as cape chisel.

coped joint, scribed joint A joint between
two moldings; one molding is cut to the profile
of the second.

coped joint

copestone Same as coping stone.

coping A protective cap, top, or cover of wall,
parapet, pilaster, or chimney; often of stone,
terra-cotta, concrete, metal, or wood. May be
flat, but commonly sloping, double-beveled, or
curved to shed water so as to protect masonry
below from penetration of water from above.
Most effective if extended beyond wall face and
cut with a drip. Also see featheredge coping.

258

cora

coping of terra-cotta

coping block A concrete masonry unit having
a solid top, for use as a coping at the top and fin-
ishing course in wall construction.

coping brick A brick which is specially manu-
factured for use as the top course in a coping;
caps the top of an exposed wall.

coping course A horizontal layer of masonry
units that forms a coping.

coping saw A light narrow-bladed saw with
fine teeth, held in a U-shaped tension frame;
used for cutting small curves in wood.

r^;

coping saw used in cutting

coping stone, capstone, copestone

which forms a coping.

A stone

coping stone

copper A lustrous reddish metal, highly ductile
and malleable; has high tensile strength, is an
excellent electrical and thermal conductor, is
available in a wide variety of shapes; widely used
for downspouts, electrical conductors, flashing,
gutters, roofing, etc.

copper alloy Metal having a specified copper
content of less than 99.3% but more than 40%
and having no other element in excess of the
copper content (except in the case of certain

copper-nickel-zinc alloys, in which zinc slightly
exceeds the copper content).

copper bit, coppering bit A gas-heated sol-
dering iron used by plumbers.

copper fitting A fitting (fabricated of wrought
copper, cast brass, or bronze) which may be
joined to copper or brass pipe by solder, screw
threads, or a compression fit.

r^ftRE

copper fitting

copper glazing Same as copperlight glazing.

copperlight glazing, copper glazing, elec-
trocopper glazing, fire-retarding glazing

A fire-retardant glazing consisting of a number
of individual panes of glass which are separated
by strips of electrically welded copper.

copperplating Depositing a protective layer of
copper on the surface of another metal, either by
the electrolytic method or by dipping.

copper roofing A flexible metal roof covering
made of copper sheets, joined by seams. As the
copper oxidizes, it develops a green coating on
its surface called a patina.

copper sheet Copper roofing material used to
cover flat, domed, or sloping roofs; usually weighs
from Vi to 2 lb per sq ft (2.5 to 10 kg per sq m).

copper slate See lead slate.

coppersmith's hammer A hammer having a
long, curved, ball-shaped peen; used to beat cop-
per sheeting into the desired shape.

copper tube A seamless tube made from
almost pure copper (99.9 percent); available
only in drawn or soft form, with plain ends.
Joints for this pipe can either be soldered or
brazed. Also see type-DWV tubing.

coquillage A representation of the forms of
seashells and the like, as a decorative carving.

coquina A soft limestone formed primarily of
broken shells and coral; cut into blocks and used
in construction.

cora A draped female figure used in architec-
ture; a caryatid.

259

CORBD

COR BD On drawings, abbr. for corner bead.

corbeil, corbeille An ornament resembling a
basket, esp. a finial. Also see calathus.

corbel l.In masonry, a projection or one of a
series of projections, each stepped progressively
outward with increasing height, and usually pro-
jecting from a wall or chimney; serves as a sup-
port for an overhanging member or course, 1
above, or as a purely decorative element. 2. A
projecting stone that supports a superincumbent
weight. 3. A heavy bracket, often decorated,
that is set into an adobe wall to act as a bearing
surface to support a roof beam.

brick wall having a corbel, 1

corbel arch Masonry built over a wall opening
by uniformly advancing courses from each side
until they meet at a midpoint. The stepped
reveals may be smoothed, even arcuated, but no
arch action is effected — not a true arch.

corbel, 2

corbel arch

corbel course A masonry course acting as a
corbel, or an ornament of similar appearance.
Also see stringcourse.

corbeled chimney cap The crowning termi-
nation of a chimney in which successive courses
of bricks step outward with increasing height.

corbeled cornice See corbie step.

corbel gable Erroneous for corbie gable.

corbeling Same as corbel, 1.

corbeling iron, corbel pin A metal pin used
(instead of corbeled brickwork) for carrying a
wall plate.

corbel out To build out one or more courses of
brick or stone from the face of a wall, forming a
support for timbers.

corbel piece See bolster.

corbel pin See corbeling iron.

corbel ring Same as annulet.

corbel-step Erroneous for corbiestep.

corbel table A projecting stringcourse or

masonry strip supported by corbels. Also see

arched corbel table.

260

core boring

corbel table

corbel vault, corbeled vault A masonry
roof constructed from opposite walls, or from a
circular base, by shifting courses slightly and reg-
ularly inward until they meet. The resulting
stepped surface can be smoothed or curved, but
no arch action is incurred.

corbie gable, crow gable, step gable A
gable having a stepped edge.

corbiestep, catstep, crowstep The stepped
edge of a gable masking a pitched roof, found in
northern European masonry, 14th to 17th cent.,
and in derivatives.

corbiestep

Corbusian style In the style of Le Corbusier
(1887-1965), the celebrated proponent of Mod-
ern architecture in France.

cord See electric cord.

corded door An accordion door fabricated of
narrow wood slats which are interconnected
with cotton cord or fabric tapes; usually sus-
pended from ceiling-mounted tracks.

cordon l.A stringcourse or belt course. 2. A
semi-circular masonry projection, placed at the
top of a wall, to discharge water to each side.

corduroy work A surface finish consisting of
a series of narrow, adjacent, parallel convex
reeds; the reverse of fluting.

core 1. The center of a plywood or crossbanded
construction; it may consist of lumber (solid or
glued) or particleboard; serves as a base for
veneer. 2. The internal structure in a hollow-
core door. 3. The wood chips cut from a mortise.

4. The metal bar to which a handrail is attached.

5. The internal structure which serves as a base
for complex plasterwork. 6. The molded open
space in a concrete masonry unit. 7. The filling
within a thick hollow stone wall. 8. The filling
between a lintel and relieving arches. 9. A cylin-
drical sample of hardened concrete or rock
obtained by means of a core barrel and drill. 10.
A part of a multistory building, containing a
variety of service and utility functions, as eleva-
tors, stairwells, etc. 11. That part of a magnetic
circuit (usually steel or iron laminations) about
which are wound coils in electromagnetic
devices such as transformers, solenoids, relays,
etc.; a magnetic core. 12. (Brit.) The conductor
of a cable with its insulation, but not including
any outer protective covering. 13. That portion
of a grille, 2 contained within the frame. 14. Of
gypsum board, the hardened material filling the
space between a face paper and a back paper;
consists primarily of gypsum with additives. 15.
(British) Same as blockout.

e,6

core area Of a grille for an air diffuser, the total
area within the outer edges of the outer opening
through which air can pass.

core barrel The hollow cutting tool of a core
drill; consists of a section of pipe which has a
carbide insert or diamond cutting edge.

coreboard, Brit, battenboard A wood-base
panel used in plywood or laminated core con-
structions; the core, 1, to which faces are glued.

core boring In the ground at a construction
site, a core obtained with a rotating tool; used to
determine the nature and/or thickness of the
underlying rock.

261

cored beam

cored beam 1. A beam having a partially hol-
low cross section. 2. A beam from which core
samples have been taken.

cored block, cored tile A cast gypsum build-
ing unit.

core bracing The vertical elements of a lateral
support system around the core, 10 of a building
having permanent interior walls.

cored cellular material Cellular material
containing a multiplicity of holes which are
molded or cut into the material in some pattern,
usually perpendicular to the largest surface, and
extending part or all the way through the piece.

core drill A drill used to remove a sample of
rock in situ, for determining bedrock profiles or
for obtaining a core for testing; the sample is
retained in the core barrel.

core driver A hardwood or steel cylinder
which is the same size as a hole through which it
is driven; used to clear the hole of chips.

cored masonry unit See hollow masonry
unit.

core frame See buck frame.

core hole In a structural clay tile, same as cell, 1 .

core module A module, 1 containing electri-
cal, heating, plumbing, and related subsystems.

core rail A steel rail, 1 that connects the tops of
balusters supporting a stair handrail.

core sample Same as core, 9.

core test A compression test on a concrete sam-
ple cut from hardened concrete by means of a
core drill.

coring Removing a core from a concrete struc-
ture or rock foundation, for test purposes.

coring out The process of removing droppings
after a parge coat has been applied to the inside
of a chimney shaft.

Corinthian capital The uppermost member
of a column of the Corinthian order.

Corinthian order In Classical architecture,
the slenderest and most ornate of the three orig-
inal Greek orders; commonly has an elaborate
cornice and a fluted shaft. For an illustration of a
Corinthian base, see bases.

cork The outer bark of the cork oak tree; light-
weight, used as thermal insulation, for gaskets,
and in vibration control.

volute

button
caulicolus

acanthus

F^l

Corinthian order

corkboard Cork granules molded to shape,
compressed, and baked in a rectangular block or
board shape or sheet form; usually 6 to 12 lb per
cu ft (96 to 192 kg per cu m) in density; used for
thermal insulation and vibration control.

corking Same as cogged joint.

corkscrew stair A spiral stair.

cork tile A resilient material composed mainly
of granulated bark of the cork oak tree and syn-
thetic resins. The surface is finished either with
a protective coat of wax, lacquer, or resin or with
a film of clear polyvinyl chloride laminated to
the top surface for easier maintenance; the nat-
ural surface requires waxing and buffing, the

262

corner chimney

vinylized surface buffing only; set in mastic over
wood or concrete subfloor.

corkwood See balsa.

corn. Abbr. for cornice.

corncrib, corn house A structure used for
storing unhusked ears of corn; designed to pro-
vide adequate air circulation to ensure that
freshly picked corn dries more or less uniformly
during storage, so as to minimize spoilage. Found
in a wide variety of sizes and shapes, but most
often the sides slope inwardly so that the area is
smaller at the bottom of the crib than at the top.
Also called a corn loft.

corner In land surveying, a point established for
marking the boundaries of landed property
either by an actual survey or by agreement
between neighbors. Monuments or other objects
may serve to designate intersection points of the
boundary lines.

corner bead, angle bead, angle staff, cor-
ner guard, corner molding, plaster bead,
staff bead 1 . Any vertical molding, usually a
plain, filleted, or quirked bead, used to protect
the external angle of two intersecting surfaces. 2.
A strip of formed galvanized iron, sometimes
combined with a strip of metal lath, placed on
corners before plastering to reinforce them.

CORNER 8EAD

corner bit brace Same as angle brace, 3.
corner block 1. See corner return block. 2. A

square, relatively flat wood block, often decora-
tively carved, placed at upper corners on each
side of the wood framing around a door.

corner board A board which is used as trim on
the external corner of a wood-frame structure and
against which the ends of the siding are fitted.

corner brace A diagonal brace let into studs to
reinforce corners of a wood-frame structure.

corner block, 2

corner board

corner brace

corner bracket A bracket which is connected
to a doorframe jamb and head at the upper hinge
corner, as a support for an exposed overhead
door closer; used only on out-swinging doors.

corner capital Same as angle capital.

corner chimney A chimney whose face forms
an angle across the intersection of two walls of a

263

corner chisel

room, as in a fogon; occasionally called an angle
chimney.

corner chisel A chisel having two cutting
edges which meet at right angles; used for cut-
ting corners of mortises.

corner clamp Same as miter clamp.

corner cracking Same as shrinkage cracking.

corner cupboard A cabinet built to fit into
the corner of a room, its face forming a 45° angle
with the adjacent walls.

corner drop A hand-carved or hand-turned
wood ornament that is suspended from a corner
of an overhanging second story of an early colo-
nial American house. See pendant, 2 and turned
drop.

corner drop suspended from a framed overhang

corner framing In a timber structure, a corner
post that provides for nailing on the exterior or
interior; often comprised of two or more studs
joined together.

corner guard See corner bead.

corner lath See corner reinforcement, 2.

corner locking Any method of joining two
timbers at a corner (for example, as in dovetail-
ing) to form a rigid joint.

corner lot A lot of which at least two adjacent
sides abut upon streets or public places, for their
full length, which must not be less than a code-
specified distance.

corner molding Same as corner bead, 1.

corner notch At a corner of a log cabin or log
house, any one of several types of notches cut near
an end of an exterior timber to form a rigid joint
when mated with another appropriately notched
timber set at right angles to it. See diamond notch,
double-saddle notch, dovetail notch, half-dovetail
notch, half-cut notch, halved-and-lapped notch,
lap notch, log notch, round notch, saddle notch,

single notch, single-saddle notch, square notch,
V-notch.

corner pilaster An engaged pier or pillar,
often with a capital and base, located at a corner
of a building or colonnade.

corner post l.In a timber structure, a post
which is placed at a corner or return angle to
provide for exterior or interior nailing. 2. A
metal mullion member which connects two
sheets of glass at an angle, forming a corner.

corner post, 1

corner reinforcement 1. In a knocked-down
or welded doorframe assembly, the reinforce-
ment at the junction of the head and jamb. 2. A
strip of expanded-metal lath bent to form a 90°
angle; used in an inside corner of a plaster wall,
ceiling, etc., to prevent cracks in plastering.
Also called corner lath. 3. See exterior corner
reinforcement.

Mj!

•ST 1 — corner

K| reinforcement

corner reinforcement, 2

corner return block, corner block A con-
crete masonry unit having a solid face at one
end, as well as solid faces on the sides.

corner return block

cornerstone 1. A stone that forms a corner or
angle in a structure. 2. A stone prominently sit-
uated near the base of a corner in a building,

264

Corporate style

/1VWE-y-7-AH°17yi

cornerstone

carrying information recording the dedicatory
ceremonies, and in some instances containing
or capping a vault in which contemporary
memorabilia are preserved; a foundation stone.

corner stud Same as corner post.

corner tile A saddle-shaped tile used in cover-
ing the hip of a roof.

corner trap A trapdoor at the front of a theater
stage, through which an actor can appear or
disappear.

corner trowel In plastering or masonry, a
hand-held trowel used to shape either inside or
outside corners.

corn house Same as corncrib.

corniccione A principal cornice at the top of a
facade.

cornice l.Any molded projection which
crowns or finishes the part to which it is affixed.
2. The third or uppermost division of an entab-
lature, resting on the frieze. 3. An ornamental
molding, usually of wood or plaster, running
round the walls of a room just below the ceiling;
a crown molding; the molding forming the top
member of a door or window frame. 4. The
exterior trim of a structure at the meeting of the
roof and wall; usually consists of bed molding,
soffit, fascia, and crown molding. For special
types, see architrave cornice, boxed cornice,
bracketed cornice, cavetto cornice, closed cor-
nice, eaves cornice, modillion cornice, open
cornice.

cornice lighting Lighting from sources which
are shielded by a panel parallel to the wall and
attached to the ceiling or to the upper edge
of the wall and which distribute light over
the wall.

cornice return The continuation of a cornice
in a different direction, as at the gable end of a
house.

cornice return

coro An elaborate choir, at times almost an
independent building, commonly placed to the
west of the transept in a Spanish cathedral.

corona The overhanging vertical member of a
cornice, supported by the bed moldings and
crowned by the cymatium; usually with a drip to
throw rainwater clear of the building. Also see

corona lucis A circle or hoop of lights or can-
dles for a church, either suspended or supported
on a stand.

coronarium In ancient Rome, stucco work
applied to the decoration of a cornice or project-
ing molding.

coronet A pedimental or other decoration
wrought in relief on a wall above a window or
door.

CORP On drawings, abbr. for "corporation."

Corporate style An austere style of industrial
buildings used in New England during the early

265

corporation cock

part of the 19th century; characterized by red
brick walls in combination with white stone lin-
tels; often gracefully proportioned.
corporation cock A valve which is placed in
a water or gas service pipe of a building, near its
junction with the public water or gas main.

WATER MAIN
corporation cock

corporation stop Same as corporation cock.

corps de logis The central part of a chateau,
large house, or mansion, not including the wings
or subordinate parts.

corpse gate Same as lych-gate.

corpsing A shallow mortise in a plaster finish
coat.

CORR On drawings, abbr. for "corrugate" or
"corrugated."

corral An enclosure for livestock, commonly for
horses.

corrected net fill The net fill corrected for
the reduction in volume resulting from com-
paction.

corrective maintenance Maintenance that
takes place after the occurrence of a failure, or in
order to restore the item or piece of equipment
to its normal working condition.

corredor In Spanish architecture, a long, nar-
row porch or arcade that often covers the entire
front and/or one or more sides of a house; or a
corridor in the house.

corridor 1. A long interior passageway provid-
ing access to several rooms. 2. A public means of
access from several rooms or spaces to an exit. 3.
An enclosed passageway that limits the means of
egress to a single path of travel. Also see exit,
passageway.

corrosion The deterioration of metal or of con-
crete by chemical or electrochemical reaction
resulting from exposure to weathering, moisture,
chemicals, or other agents in the environment
in which it is placed.

corrosion inhibitor Any of a number of mate-
rials used to prevent the oxidation of metals;
may be a coating applied to the surface, a paint
undercoat, or an element alloyed with the metal.

corrugated aluminum l.See corrugated
metal. 2. When perforated, a facing for a sound-
absorptive blanket in some acoustical ceiling
constructions.

corrugated asbestos A siding or roofing
material fabricated in the form of corrugated
asbestos cement board.

corrugated fastener, joint fastener A steel
fastening device used to join corner pieces in
rough carpentry; one side of a small corrugated
strip is sharpened so that it may be driven into
the two wood pieces to be joined; used only
where appearance is not important.

corrugated fastener

corrugated glass Glass which has been corru-
gated to provide greater diffusion of light.

corrugated iron Sheet steel (usually galvanized)
which has been fabricated as a corrugated metal.

corrugated metal Sheet metal which has been
drawn or rolled into parallel ridges and furrows to

266

Cottage style house

provide additional mechanical strength; alu-
minum and galvanized sheet steel are widely used.
corrugated roofing A roofing material in
sheet form, usually of galvanized metal or cement
asbestos, shaped into alternate ridges and valleys.

corrugated-roofing nail Same as roofing nail.

corrugated tubing Same as flexible seamless
tubing.

corsae In Classical Roman architecture, fillets
or moldings used to decorate the external face of
a marble doorpost.

corseria A passageway, from one tower to
another, along the walls of a medieval town or in
a castle.

cortile An interior courtyard enclosed by the
walls of a palazzo or other large building; often
arcaded.

cortina In Spanish, literally, a curtain. In Span-
ish architecture or its derivatives, corbeled
stonework directly below a balcony or windowsill.

corundum A hard, abrasive mineral, princi-
pally aluminum oxide, applied to a surface to
make it non-slippery; for example, on the walk-
ing surface of a ramp.

cosine law See Lambert's cosine law.

Cosmati work Polychromatic patterns of
stone, glass, or gilding set in marble; commonly
applied in Italian Romanesque architecture.

cost adjustment On a construction project, a
change (for any reason) in the total contract
cost which is agreed to by the owner, the archi-
tect, and the contractor.

cost-benefit analysis An analysis of a con-
struction contract with the objective of identify-
ing all the included costs and evaluating their
benefits.

cost breakdown See schedule of values.

cost consultant A professional who, by train-
ing and experience, provides expert advice on
construction costs.

cost control Management of a project to
ensure that construction costs do not exceed the
budgeted amount.

cost of construction The sum of all direct
and indirect costs of construction; generally cat-
egorized as equipment costs, job overhead costs,
operating overhead costs, material costs, plant
costs, and profit.

cost of light See lighting cost.

cost-plus-fee agreement An agreement under
which the contractor (in an owner-contractor
agreement) or the architect (in an owner-
architect agreement) is reimbursed for his direct
and indirect costs and, in addition, is paid a fee for
his services. The fee is usually stated as a stipulated
sum or as a percentage of cost.

cost proposal The response made by a con-
tractor who is proposing anticipated changes in
the cost of construction after the architect has
issued a proposal request.

cot A small house or cottage.

cot bar A glazing bar which connects the radial
bars of a fanlight.

cotloft (Brit.) See loft, 2 .

cottage l.A relatively small house, often in a
village, in the countryside, in a suburb, or at the
seashore. 2. A small vacation house. 3. A
dwelling, often temporary, that provides only
basic shelter. 4. An imposing mansion (as found
in Newport, Rhode Island). Also see banquette
cottage, Cajun cottage, Chicago cottage, Dutch
cottage, Normandy cottage, one-and-one-half
bay cottage, one-bay cottage, one-room cottage,
palma cottage, prairie cottage, raised cottage,
tidewater cottage, two-bay cottage.

cottage hospital l.An institution in which
patients are housed in relatively small, home-
like units, each providing eating and living
space for a small group. 2. (Brit. ) A small hospi-
tal served by local nonspecialist physicians.

cottage orne A small, picturesque house in a
rural or country setting, primarily in the late 18th
and early 19th centuries. Some cottages were so
classified because straight tree trunks were used
as columns and selected parts of tree branches
were used as brackets; others were placed in this
category merely because their ornamentation
was said to create a picturesque effect.

cottage roof A roof which has common rafters
that rest on wall plates and are joined at their
upper ends in a ridge; no principal beams are
used.

Cottage style house l.A style of domestic
architecture, usually of wood construction, pop-
ularized in the 19th century, primarily by the
pattern books of architects Andrew Jackson
Downing (1815-1852) and Alexander Jackson

267

cottage window

Cottage style house

Davis (1803-1892); usually included many of
the following characteristics: an asymmetric
plan, walls of board-and-batten construction,
balconies, decorative chimneys, steeply pitched
roofs, and bay windows. 2. A loose term infre-
quently applied to a bungalow.

cottage window A double-hung window hav-
ing its upper sash smaller than the lower sash;
the upper pane is often decorated.

cotter A beveled piece of wood or steel, used as
a wedge for fastening.

cotter pin A metal pin used for fastening; the
split ends which project beyond the pin hole are
bent back from the axis of the pin.

cotter pin:

above: below, installation

cotton mats Cotton-filled quilts fabricated for
use as a water-retaining covering in curing con-
crete surfaces.

coulisse, cullis l.A piece of channeled or
grooved timber, as one in which a frame slides.
2. An area backstage in the theater, esp.
between two wing flats.

council school (Brit. ) An elementary or sec-
ondary school supported by public taxes; similar
to public school in US.

count In wire cloth, the number of openings per
linear inch.

counter 1 . A long horizontal surface used in
stores, shops, banks, etc., for display of goods, for
work-top areas, or for business transactions. 2.
The top or working surface of the base of a
kitchen cabinet.

counter apse An apse which is opposite
another apse. Many such double apses have a
crypt below the western apse.

counter arch An arch used to counteract the
thrust of another arch.

counterbalanced window A double-hung
window constructed so that the weights of the
upper and lower sashes balance each other.

counterbalance system Same as counter-

weight system.
counter batten A furring strip which is below,

and at right angles to, the battens.

counterbore To enlarge a hole to receive the
head of a bolt or a nut.

counterbrace A brace which counteracts the
strain of another brace, as a web member of a
truss.

counterbracing A system of counterbraces.

counterceiling Same as false ceiling.

counter cramp A construction joint used to
join segments of built-up stair stringers or
counter tops. Slotted strips of wood are
secured along the face of the stringers at the
joint. Thin folding wedges are inserted in the
slots to align the strips and thereby tighten
the joint.

counterflashing, cover flashing, cap flash-
ing A strip of sheet metal, often built into
masonry and turned down over other flashing;
used to prevent water from entering the joints
and the exposed upturned edges of base flashing
on a roof.

BASE
V FLASHING

counterflashing

268

coupler

counterfloor See subfloor.

counterfort In masonry structures, a but-
tress, spur wall, pier, or projecting portion,
extending upward from the foundation or
from the inner face of a basement, abutment,
or retaining wall to provide additional resis-
tance to thrust.

counterfort wall A cantilever wall that is
reinforced with counterforts or buttresses.

counter gauge Same as mortise gauge.

counterguard In a medieval fort, a structure
placed in a ditch in front of a bastion to provide
additional protection.

counter-imbrication See contre-imbrication.

counterlathing See cross-furring.

counterlight A light or window directly oppo-
site another.

countermure A wall between the inner wall
and outer wall of a fortification, either to pro-
vide additional defense or as an aid to the
besieger.

counter»relief A carving, casting, or embossed
design which is sunk below the general surface
area.

counterscarp The face of the ditch of a
fortress sloping toward the defender.

counterscarp wall The revetment of a coun-
terscarp, usually made of stone or brick, but
occasionally of timber.

countersink A boring bit having a conical-
shaped cutter; used to make a depression to
receive the head of a screw or bolt so that it does
not protrude above the surface.

countersink

countersunk bolt A bolt having a circular
head with a flat top and a conical bearing surface
which tapers in from the top; when in place, the
head is flush-mounted.

countersunk bolt

countersunk rivet A rivet used in counter-
sunk holes in which the point, while hot, is
hammered down to fill the countersinking.

countervault An inverted arch.

counterwall l.A wall of a building that is
adjacent to, but separated from, the end wall
of a building; party wall. 2. Same as counter-
mure.

counterweight l.A weight that just balances
another weight. 2. In a theater stagehouse, a
weight (usually of iron, sand, or shot) used to
balance suspended scenery, or the like.

counterweight arbor A movable frame in
which are stacked the modular counterweights
of a counterweight system.

counterweighted window A window hav-
ing sashes, each of which is counterbalanced
with a weight.

counterweight safety See elevator car safety.

counterweight system A permanent, over-
head, theater stage rigging system; used to raise
or lower scenery or lighting equipment which is
counterbalanced by counterweights that ride in
vertical tracks at the side of the stage.

counting house A building once used primar-
ily for accounting and bookkeeping.

country seat A rural residence of some impor-
tance.

couple Two equal and opposite parallel forces,
with different lines of action, tending to pro-
duce rotation of a body; their moment equals
the product of the magnitude of one of the
forces and the perpendicular distance between
them.

couple-close, close couple A pair of oppo-
site rafters which are connected by a collar
beam or tie beam and are tied together at the
apex.

coupled arcade An arcade supported on cou-
pled columns.

coupled columns Two closely spaced columns
that form a pair. (See illustration p. 270.)

coupled pilasters Two closely spaced pilasters
forming a pair.

coupled windows Two closely spaced win-
dows which form a pair. (See illustration p. 270.)

coupler A metal hardware device used to join
frames and braces of tubular metal scaffolding.

269

couple roof

coupled columns

coupled windows

couple roof, coupled roof A double-pitched
roof, usually of narrow span, in which opposite
rafters are not tied together; the walls resist the
outward thrust.

couples Terminology once used to designate a
pair of rafters.

coupling A short internally threaded section of
pipe, used to join two pipes or conduits.

coupling

coupling pin A pin, 1 which is used to connect
lifts or tiers or formwork scaffolding vertically.

cour d'honneur The forecourt of a building,
especially a monumental forecourt.

course 1. A layer of masonry units running hor-
izontally in a wall or, much less commonly,
curved over an arch; it is bonded with mortar. 2.
A continuous row or layer of material, as shin-
gles, tiles, etc. 3. In concrete construction, one
of several horizontal layers making up a lift, 5.
For specific types, see band course, base course,
belt course, blocking course, bond course, cop-
ing course, corbel course, dog-tooth course,
masonry course, random course, sill course,
springing course, staggered course, stringcourse,
tumbling course.

course, 1

coursed ashlar, range masonry, range-
work, regular coursed rubble Ashlar
masonry in which the stones are of equal height
within each course; all courses need not be of
the same height.

coursed masonry, course work Masonry
construction in which the stones are laid in reg-
ular courses, not irregularly as in rough or ran-
dom rubble.

coursed pattern A pattern formed by shingles
that are laid in regular horizontal rows of equal
height, each row overlapping the row below,
with the vertical joints of one row usually falling
approximately midway between those of the row
below.

coursed rubble Masonry construction in which
roughly dressed stones of random size are used, as
they occur, to build up courses; the interstices
between them are filled with smaller pieces, or
with mortar.

coursed square rubble Same as random
ashlar.

270

cove header brick

coursed rubble

coursed veneer In stone masonry, the use of
veneer stones having equal height to form each
continuous course, with horizontal joints
extending the full length of the facade; the ver-
tical joints are broken so that no two vertical
joints form a continuous line.

course-grained Said of wood from a tree hav-
ing wide, conspicuous annual rings.

course work See coursed masonry.

coursing joint A horizontal or arched mortar
joint between two courses of masonry in a wall
or arch.

court l.An open, uncovered, and unoccupied
space partially or fully surrounded by walls or build-
ings. 2. A courtroom. 3. Residence of a dignitary or
member of royalty and its enclosed grounds.

courthouse l.A building in which are con-
tained rooms for courts of law, judges' chambers,
offices of clerks of court, and, sometimes, other
official offices. 2. A building containing county
administrative offices, often including the
county jail.

courtroom The main room in a courthouse
where the judge presides.

courtyard An open area that is partially or
fully enclosed by one or more buildings and/or
by walls. Courtyards that are enclosed or par-
tially enclosed by walls are sometimes referred to
as patios. Also see placita.

coussinet l.The stone which is placed on the
impost of a pier to receive the first stone of an
arch. 2. The part of the front of an Ionic capital
between the abacus and echinus.

cove A concave surface or molding, especially
placed at the transition from a wall to the ceil-
ing, or from a wall to the floor.

cove base A conge, 2.

cove bracketing A series of wood brackets or
the framing set to receive the laths for a cove, as
in constructing a cove ceiling.

coved base A trim piece at the base of a wall
forming a concave rounded intersection with
the floor.

coved ceiling A ceiling having a cove at its
intersection with the wall.

cove ceiling

coved eave That part of a roof that projects
beyond the exterior wall, the underside of which
is covered with a concave surface so that the
rafters are not visible.

coved eave

coved vault, cloistered arch, cloistered
vault A vault, 1 composed of four quarter-
cylindrical surfaces or coves, meeting in vertical
diagonal planes, the axial sections of the vault
being arched, and the horizontal courses dimin-
ishing in length from spring to crown. (See illus-
tration p. 272.)

cove header brick, cove header A brick
having one end that is molded or shaped with a
cove or concave curve.

271

cove lighting

coved vault

cove lighting Lighting from sources which are
out of sight, atop a wall molding; shielded by a
ledge or horizontal recess, and which distribute
light over the ceiling and upper walls.

covemold frame A steel doorframe having a
cross section which is similar in shape to a
wood doorframe with a cove molding at its
outer edge.

cove molding, cavetto A molding having a

concave face; often used as trim.
covenant See restrictive covenant.
covenanter door Same as Christian door.

cover l.In reinforced concrete, the least dis-
tance between the surface of the reinforcement
and the outer surface of the concrete. 2. That
part of a tile or shingle which is covered by the
next course. 3.The concrete (or concrete-like
material) which covers steel reinforcement to
protect the steel from possible fire damage or cor-
rosion.

coverage 1 . A measure of the area over which a
gallon of paint may be spread at a given thick-
ness, usually expressed as square feet per gallon
at 1 mil dry film. 2. The amount of surface that
can be covered by a particular amount of roofing
material. 3. The ratio of the area of the footprint
of a building to the total area of the site on
which it is located.

cover block Same as spacer.

cover coat In ceramics, the layer of porcelain
enamel normally applied over a ground coat.

covered bridge A roofed bridge, typically con-
structed of heavy timbers and trusses, enclosed
or partially enclosed on its sides; especially
found in regions having heavy snowfall.

covered joint A lap joint.

covered shaft An interior enclosed space
that extends through one or more stories of a

building, connecting openings in successive

floors, or the floors and roof; must be covered at

the top.
cover fillet See cover molding.
cover flange Same as escutcheon.
cover flap A hinged flap which covers boxing

shutters.
cover flashing See counterflashing.

covering capacity A term now replaced by
hiding power.

covering power See hiding power.

cover molding, cover fillet A wood strip
covering a joint, as between sections of paneling.

cover plants Plants, usually low-growing, used
to cover soil so as to prevent its erosion.

cover plate 1. A plate fastened on the flanges
of a girder to give it additional cross section. 2.
A top or bottom plate of a chord, 1 ; also called
flange plate.

coverport In a medieval fort, a small defensive
structure that provides protection for the front
of a gate.

coverstone A flat stone which is laid on a steel
beam or girder and serves as a foundation for the
masonry laid on it.

cover strip A thin strip used to cover a butt
joint.

cover tile Same as imbrex.

covertway A walkway atop a counterscarp.

coving 1. Coves. 2. Vertical outward curve of
an exterior wall, esp. to meet eaves or a jetty.
3. A concave molding along a rood beam to sup-
port a loft or gallery. 4. The curved or splayed
jambs of a fireplace which narrows toward the
back.

cow barn, cow house, cow shed A depen-
dency used to house cattle.

cowl A protective hood on a vertical pipe (such
as a soil stack or vent pipe); used to exclude rain-
water and snow.

cownose-brick A brick having a semi-circular
end.

cp Abbr. for candlepower.

CP On drawings, abbr. for cesspool.

CPFF Abbr. for "cost plus fixed fee."

CPM Abbr. for critical path method.

cpm Abbr. for "cycles per minute."

272

cramp

cps Abbr. for "cycles per second"; same as Hz,

abbr. for hertz.
C-purlin See C-section.

CPVC Abbr. for "chlorinated polyvinyl chlo-
ride."

CR 1. Abbr. for "cold-rolled." 2. Abbr. for "ceil-
ing register."

Cr Abbr. for "cross."

crab l.A short shaft or axle, mounted on a
frame, having squared ends to receive hand
cranks; used to wind up a rope carrying a load.
2. See crocket.

crabwood See carapa.

crack A building defect consisting of complete or
incomplete separation within a single element or
between contiguous elements of constructions.

crack-control reinforcement Steel rein-
forcement in concrete construction to prevent
cracks or to limit them to small, uniformly dis-
tributed ones.

cracked section A section which is either
designed or analyzed on the assumption that
concrete has no resistance to tensile stress.

cracking See crazing, alligatoring, crawling,
hairline cracking.

cracking load That load which causes the ten-
sile stress in a structural concrete member to
exceed the tensile strength of the concrete.

crackle In painting, a paint or lacquer designed
to develop a network of fine cracks when applied
over a softer undercoat.

crack length The total length of all cracks
measured along the outer edges of window frames
and the inner faces of stops or beads around sash;
used to determine the air infiltration of the entire
window when the air-infiltration rate is known.

cradle 1. See chimney foundation. 2. The
structural support for a pipe which is placed
below and to one side of the pipe.

cradle roof A barrel roof, 1 .

cradle vault Same as barrel vault.

cradling Timber framing for supporting the
lath and plaster or masonry of a dome or vaulted
ceiling.

Craftsman style A domestic architectural
style in America in the first few decades of the
20th century, greatly influenced by the Arts and

Craftsman style: upper hall of a residence

Crafts movement. Houses in this style were usu-
ally characterized by: a nonsymmetrical facade,
typically sheathed with stucco, wood clapboard,
or wood shingles, and less often with board and
batten, brick, concrete block, or stone; often,
masonry walls on the first story and clapboard or
wood shingles on the second story; occasionally,
a battered foundation; a gabled porch, recessed
or trellised, facing the street; commonly a porte
cochere at one side of the porch; usually a low to
moderately pitched front-gabled roof; exposed
roof rafters, beams, false beams, or triangular
knee braces inserted as decorative elements
under the gables; gabled dormers or shed dorm-
ers with exposed beams; double -hung windows
or heavily framed casement windows. The inte-
rior commonly featured a high wainscot that was
integrated with the doors and windows as part of
the structural decoration. The stairway from the
living room to the floor above was often an
important design element.

cragstone Same as corbel, 2.

crail work Ornamental ironwork.

cramp l.A U-shaped metal fastening to hold
adjacent units of masonry together, as in a

cramp, 1

273

cramp iron

parapet or wall coping; a cramp iron. 2. A rect-
angular frame, with a tightening screw, used to
compress joints between wood pieces during
gluing. 3. A device for holding a frame in place
during construction.

cramp iron A cramp, 1.

crampon A lifting device (for rocks, timbers,
etc.) having two steel spikes which grasp the load.

crandall A hammer- like tool having a number of
sharp, pointed steel rods which are held in a slot
at the end of a handle; used for dressing stone.

crandall

crane 1 . A machine for lifting or lowering a
load and moving it horizontally, in which the
hoisting mechanism is an integral part of the
machine; classified by mounting, by boom con-
figuration, and by lifting capacity. 2. See fire-
place crane.

crane boom See boom, 2.

crane gantry See gantry crane.

crank arm operator Same as roto operator.

crank brace Same as brace, 3.

crapaudine door, center-pivoted door A

door which rotates on pivots set into the lintel

and the doorsill rather than about one vertical

edge.
crash bar The cross bar of a panic exit device;

serves as a push bar to actuate the panic hardware.
cratchet An upright tree trunk having a natural

fork at its upper end; the Y of the fork is used to

support the ridgepole of the roof.

cratchet

cratering The formation of small craters in a
paint film, caused by bursting bubbles of air
which were trapped during application.

crawl The movement of paint in a wet paint
film that does not remain evenly spread but
redistributes itself after application, usually as a
result of an imperfect bond with the surface.

crawl boards Boards placed on roofing that are
intended to protect it against heavy foot traffic.

crawler tractor An engine-driven vehicle
that travels on segmented roller-chain tracks
designed to reduce ground pressure and increase
traction in loose footing; powesed by a gasoline
or diesel engine.

crawler tractor

274

creep strength

crawling l.A defect in porcelain enamel,
appearing as agglomerates or irregularly shaped
"islands." 2. A parting and contraction of the
glaze on the surface of ceramic ware during dry-
ing or firing, resulting in unglazed areas bordered
by coalesced glaze.

crawling board A plank with cleats spaced and
secured at equal intervals, for use by a worker on
roofs; not designed for transporting material.

crawl space l.Any interior space of limited
height, but sufficient to permit workmen access
to otherwise concealed ductwork, piping, or
wiring. 2. In a building without a basement, an
unfinished accessible space below the first floor
which is usually less than a full story in height;
normally enclosed by the foundation wall. 3. A
creep trench.

crawl space, 2

crawlway A crawlspace having one dimension
that is many times larger than the other two.

crazing, cracking, craze cracks Fine, random
cracks or fissures in a network on or under a surface
of plaster, cement, mortar, concrete, ceramic coat-
ing, or paint film; caused by shrinkage.

crazy paving Randomly set paving stones hav-
ing neither a definite shape nor a fixed size.

crease tile See crest tile.

creasing 1 . One or more courses of tiles or
bricks laid upon the top of a wall or chimney
with a projection of 1 to 2 in. (2.5 to 5 cm)
for each course over the one below, to throw

off water; if there is coping, it is placed above
the creasing. Also called a creasing course,
tile creasing. 2. A layer of slates or of metal over
a projecting string-course or window cap, serv-
ing as a flashing to prevent the infiltration of
moisture.

creasing course Same as creasing, 1.

credence A small stand or shelf near an altar to
hold the elements of the Eucharist: church ves-
sels, service books, etc.

credence

creekstone A quartzite stone that has been
worn smooth by the action of flowing water.

creep l.The continuing, time-dependent part
of strain resulting from stress; the permanent and
continuing dimensional deformation of a mate-
rial under a sustained load, following the initial
instantaneous elastic deformation. 2. Slow move-
ment of rock debris or soil, usually imperceptible
except in observations of long duration. 3. In
structures, particularly of concrete, permanent
deflection of structural framing or structural
decking resulting from plastic flow under contin-
ued stress. 4. In roofing, permanent elongation or
shrinkage of a roofing membrane resulting from
thermal or moisture changes. 5. The flow of
water along the interface between a structure and
the surrounding soil or rock foundation.

creeper l.A brick in the wall adjacent to an
arch, cut to conform to the curvature of the
extrados. 2. (pi.) Same as crocket.

creep strength The stress that produces a
given rate of creep at a specified temperature.

275

creep trench

creep trench A low underfloor horizontal pas-
sageway, usually less than 3^4 ft (1 m) high. Also
see crawl space.

crematory, crematorium A building for the
incineration of the human dead.

cremone bolt, cremorne bolt A type of
hardware for locking French windows or the
like; a rotating handle actuates sliding rods
which move in opposite directions, extending
from the edges of the window into sockets that
are fixed in the frame.

cremorne bolt See cremone bolt.

crenation One of a series of rounded projec-
tions or teeth forming an edge.

crenel, crenelle An open space between the
merlons of a battlement.

crenelated, crenellated 1. Having battle-
ments. 2. Bearing an embattled pattern of
repeated indentations.

crenelated molding, crenellated molding,
embattled molding A molding notched or
indented to represent merlons and embrasures in
fortification.

crenelated molding

crenelet l.A small crenel, whether in an
actual battlement or in a decorative design imi-
tating one. 2. A small arrow loop.

crenellation See battlement.

crenellation

Creole house A house developed by the Creoles
(i.e., French-speaking persons of European ances-
try born in the Gulf Coast or environs in the early
18th century) designed to provide reasonable
comfort under the local conditions of high tem-
perature and high humidity; usually rectangular in
plan, with one or two rooms, a garret overhead; a
bonnet roof or a roof having a single slope on each
side of a central ridge; usually a raised house sur-
rounded (or partially surrounded) by a full-length
porch along one or both sides of the house; the
rooms are entered through French doors from the
porch. The floor on which the family lived was
raised well above ground level to improve the air
circulation. Compare with Cajun cottage.

elated

Creole house

276

crick

creosote An oily liquid obtained by distilling
coal tar; used to impregnate wood (as a preserv-
ative) and to waterproof materials. Also called
dead oil and pitch oil.

crepido A raised base on which other things are
built or supported, as an ancient Roman temple
or altar.

crepidoma The base courses (a stepped plat-
form) of a classical (esp. Greek) temple. Also see
stylobate.

crescent A building or series of buildings whose
facades follow a concave arc of a circle or ellipse
in plan.

crescent arch A horseshoe arch.

crescent truss A truss in which the top chord
and the bottom chord are either both curved
upward or both curved downward; having differ-
ent radii of curvature, the chords intersect at the
ends, forming a crescent profile; between the
chords is a web.

crescent truss

cresset stone In a medieval church, a stone
which has been hollowed out to hold oil. A wick
set in the oil, when lighted, provides illumina-
tion for the surrounding area.

cress tile See crest tile.

crest l.A finial. 2. An ornament of a roof, a
roof screen, wall, or aedicula, generally rhythmic
and highly decorative, and frequently perfo-
rated; cresting.

crest, 2

cresting See crest, 2.

crest tile, crease tile, cress tile l.Tile

which fits like a saddle on the ridge of a roof. 2.
Tile forming a crest, 2.
CRI Abbr. for "color rendering index."

crest tiles, 1 :

crest tiles, 2

crib 1 . A lining of a shaft, such as a framework of
timbers. 2. A framework constructed of squared
timbers, steel, or concrete members; used as a
retaining wall or to provide support for construc-
tion above. 3. A partial enclosure for storing
hay, corn, or the like; also see corncrib.

crib wall A framework of wood, concrete, or
metal members used as a retaining structure; see
cribbing, 2.

crib barn A crudely constructed barn once
used to house animals or to store agricultural
products; usually timber-framed, but sometimes
built of logs. If constructed with one storage
space, it was called a single-crib barn; if two stor-
age spaces, a double-crib barn; if four storage
spaces, a four-crib barn.

cribbing 1 . A system of cribs, 2. 2. A framework
of wood, concrete, or metal members which form
open bins that are filled with crushed rock or per-
vious soil; used as a retaining structure for an
earth embankment. 3. A framework of timber
mats, steel members or plates, etc., used as a sup-
port for mobile cranes, or the like.

cribbled Covered with dots, raised or sunk
(describing a surface or background). Also see
scumbled.

crib test A test for rating combustible proper-
ties of treated wood which is exposed to fire.

cribwork 1 . A construction of timber made by
placing horizontal beams one above the other
and fastening them together, each layer being at
right angles to those above and below it. 2.
Same as cribbing.

crick A small jackscrew.

277

cricket

cricket, saddle A small saddle-shaped projec-
tion on a sloping roof; used to divert water
around an obstacle such as a chimney.

cket

crimp l.To bend or warp. 2. To offset a struc-
tural steel member so that it will fit over the
flange of another member.

crimped copper Copper in sheets or strips
having small transverse corrugations to provide
for expansion, to increase rigidity, or to serve as
ornamentation.

crimped wire A wire having a series of small
curves in it; these deformations are provided
to increase the capacity of the wire to bond to
concrete.

crimping A process similar to corrugating, but
providing a surface (essentially flat) with regu-
larly spaced small ridges.

crinkle-crankle (Brit.) A serpentine wall,
esp. in the 18th century. Same as serpentine wall.

crinkled On a porcelain enamel surface, a tex-
tural effect having the appearance of fine wrin-
kles or ridges.

crinkling See wrinkling.

cripple l.In a building frame, a structural ele-
ment that is shorter than usual, as a stud above a
door opening or below a windowsill. 2. In roof-
ing, a bracket that anchors at the ridge line and
carries scaffold platforms for roofing workers.

cripple rafter A jack rafter.

cripple stud A cripple, 1.

cripple wall A stud wall less than a full story in
height.

cripple window (Brit. ) A dormer window.

crippling load British term for buckling load.

criss A jig for forming crest tiles.

criterion 1 . A standard or rule on which a deci-
sion or judgment may be based, forming the basis

cripples, 1

for the establishment of acceptable limits of
environmental conditions in buildings. 2. An
established code, measure, norm, or rule upon
which a decision may be based.

critical angle An angle of pitch of stairs or a
ramp which is considered uncomfortable and
unsafe if exceeded; this angle is 50° for stairs and
20° for ramps.

critical density That unit weight of a satu-
rated granular material above which it will gain
strength and below which it will lose strength
when subjected to rapid deformation.

critical height The maximum height at which
a vertical cut in a cohesive soil will stand unsup-
ported.

critical level The setting on a backflow pre-
venter or vacuum breaker which determines its
minimum permitted elevation above the flood-
level rim of the fixture or receptacle served.

critical load The load, 1 on a member or struc-
ture at which failure is likely to occur.

critical path The longest irreducible sequence
of work activities which determines the mini-
mum duration of a construction project.

critical path method, CPM A system of
project planning, scheduling, and control which
combines all relevant information into a single
master plan, permitting the establishment of the
optimum sequence and duration of operations;
the interrelation of all the efforts required to
complete a construction project are shown; an
indication is given of the efforts which are criti-
cal to timely completion of the project.

278

cross bar

critical section In structures, that section or
position where failure is most likely to occur.

critical slope The maximum angle with the
horizontal at which a sloped bank of soil of given
height will stand unsupported.

critical speed The angular speed of rotating
machinery at which excessive vibration is
produced; at this speed the periodic disturbing
force coincides with a mechanical resonance
of the shaft and/or of the machinery or its
supports.

critical temperature 1. The temperature at
which a steel structure cannot carry the service
load for which it was designed because of soften-
ing of the steel that occurs when it is heated sig-
nificantly. 2. Same as self-ignition temperature.

critical velocity Of a liquid flowing in a pipe,
the velocity at which the flow changes from lam-
inar flow to turbulent flow.

critical void ratio That void ratio which cor-
responds to the critical density.

CRMS Abbr. for cold-rolled mild steel.

crocidolite Same as riebeckite asbestos.

crocket In Gothic architecture and derivatives,
an upward-oriented ornament, often vegetal in
form, regularly spaced along sloping or vertical
edges of emphasized features such as spires, pin-
nacles, and gables.

cket

crock tile A glazed clay drain tile, sometimes
with bell-shaped ends.

crocodiling See alligatoring, 1.

croft An undercroft.

croisette Same as crossette.

cromlech 1 . A monument of prehistoric or
uncertain date consisting of an enclosure formed
by huge stones planted in the ground in a circle.
2. A dolmen.

crook 1 . The warp of a board edge from a
straight line drawn between the two ends; also
called edgebend or spring. 2. A piece of timber
so warped; a knee.

crook rafter A knee rafter.

crop, crope A bunch of foliage worked or
sculptured at the top of a spire, finial, or similar
decorative member, and having a resemblance
to the top of a plant.

croquet Same as crocket.

crosette Same as crossette.

cross l.An object consisting primarily of two
straight or nearly straight pieces forming right
angles with one another; the usual symbol of the
Christian religion. 2. A monument or small
building of any kind surmounted by a cross, 1, as
a market cross. 3. A pipe cross.

crocket capital A capital having a series of
crockets.

crocking A paint defect that permits color to
be removed from a surface by rubbing.

cross, 3

cross aisle l.In a church, a transverse aisle
between pews. 2. In an auditorium, an aisle usu-
ally parallel to rows of seats, connecting other
aisles or an aisle and an exit.

cross-and-bible door Same as Christian door.

crossband, crossbanding, cross core l.In

plywood, a veneer sheet whose grain is at right
angles to the face veneer. 2. Any decorative
band whose grain is perpendicular to the princi-
pal surface. (See illustration p . 280.)

cross bar In a grating, one of the connecting
bars which extend across bearing bars, usually
perpendicular to them; where they intersect
the bearing bars, they are welded, forged, or
mechanically locked to them.

279

cross bar centers

FACE VENEER

CROSSBANDING
CORE

CROSSBANDING
BACK VENEER

crossbanding, 1

cross bar centers In a metal grating, the dis-
tance between centers of the cross bars.

cross batten A batten, 2.

cross beam, crossbeam l.A large beam
between two walls. 2. A girder that holds the
sides of a building together. 3. Any beam that
crosses another. 4. A strut between the walings
on opposite sides of an excavation. 5. A beam
which runs transversely to the center line of a
structure. 6. Any transverse beam in a structure,
such as a joist.

cross»bedding In sedimentary rocks, inclined
laminations or bedding which lends textural and
color pattern to building stone of such material.

cross bond A masonry bond in which courses
of Flemish bond alternate with courses of
stretchers; the joints in the courses above and
below the stretchers are opposite the centers of
the stretchers.

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cross bond

cross brace Same as X-brace.

cross bracing l.Any system of bracing in
which the diagonals intersect; also called X-
bracing. 2. Horizontal timbering which extends
across an excavation so as to support a cofferdam
or sheathing. 3. Braces that cross from one col-

umn to the next to increase the load-bearing
capacity of the combination.

cross break Separation in wood in a direction
perpendicular to the normal grain direction.

cross bridging, diagonal bridging, herring-
bone strutting Diagonal bracing (in pairs)
between adjacent floor joists to prevent the
joists from twisting.

cross bridging

cross»church A cruciform church; one having
a cross-shaped ground plan.

cross-connection l.A connection between
two otherwise separate piping systems, one con-
taining potable water and the other water which
may be contaminated. 2. In a fire-protection sys-
tem, a piping connection from a Siamese con-
nection to a standpipe or to a sprinkler system.

cross core See crossbanding.

crosscut Cut at right angles to the grain.

crosscut saw A saw adapted by its filing and
setting to cut across the grain of wood rather
than with the grain.

KERF

AAAM t

HANDLE-

BLADE

TOP VIEW

HEEL

crosscut saw with details showing saw teeth

crossette l.A decorative embellishment, such
as a molding around one corner of a door, window,
or fireplace opening, that somewhat resembles a
squared-off ear; especially popular during the lat-
ter half of the 18th century; also called a dog's ear.

280

cross house

crossettes, 1

crossettes, 2

2. A small projecting part of a voussoir (arch
stone), which hangs upon an adjacent stone.

cross fall On the surface of the ground, the gra-
dient across the width of a building.

cross fire, cross figure A fiddleback grain
pattern.

crossflow filtration A water filtration process
in which a semipermeable membrane is used to
separate waterborne contaminants from the
water. The bulk solution flows over and parallel
to the filter surface, and under pressure, a por-
tion of the water is forced through the mem-
brane filter.

crossflow filtration

cross-furring, brandering, counterlathing

Strips, flat bands, or fillets which are applied on
the undersides of joists to which lath (for plas-
tering) is nailed; usually attached perpendicular
to the main framing members.

cross gable A gable which is set parallel to the
ridge of the roof.

cross gables

cross-garnet hinge A hinge shaped like the
letter T; the longer part is fastened to the door
leaf and the shorter to the frame.

cross girder Any beam which unites longitudi-
nal girders.

cross grain Grain in wood not parallel with the
long dimensions, or irregular gnarled grain.

cross grain

cross-grained float A wooden float having
the grain of the wood parallel to the short side of
the float. Used for leveling and scouring the sur-
face of plaster or cement.

crosshairs Crossed wires or etched lines on a
reticule in the focal plane of the telescope of a
surveying instrument.

cross house, cross-plan house A masonry
house having a cruciform plan (i.e., shaped
like a cross); especially found in colonial
Maryland and Virginia. At the front of the
house, entry was through a front door in a two-
story extension in the transverse direction of

281

crossing

cross house

the cross; at the rear of this extension was an
enclosed porch on the ground floor containing
a small, steep stair leading to a room above.
Meals were usually prepared in an outkitchen
near the house.

crossing l.In a church, the place where the
nave and chancel cross the transept. 2. A paint-
ing technique whereby freshly applied paint is
rebrushed at right angles to the direction of
application and then rebrushed at right angles
again to provide even distribution of paint over
the surface. 3. Same as crossbanding.

cross-in-square plan Said of the plan of an
early Christian church that was divided into
nine bays; the central bay was a large square with
a dome over its center; the four corner bays were
each small, domed, and square in plan; the
remaining four bays were barrel vaults.

cross joint See head joint.

cross-laminated Laminated so that some lay-
ers of material are oriented at right angles to the
remaining layers with respect to the grain or to
the direction in which tension is greatest.

crosslap joint A joint connecting two wood
members which cross each other; half the thick-
ness of each is cut away so that the thickness at
the joint is the same as that of each member.

crosslap joint

crosslight Light received from windows at right
angles to each other.

crosslighting Lighting an object from two oppo-
site sides.

crosslot bracing The horizontal compression
members that run from one side of an excava-
tion site to the other; used to support sheeting.

cross main Pipes which supply the branch
lines, 2, either directly or through risers.

cross nogging Bracing between common joists
which is arranged in a herringbone pattern.

crossover 1. A connection between two pipes
in the same water-supply system, or between two
water-supply systems containing potable water.
2. A pipe fitting shaped like the letter U with
the ends turned outward; used where one pipe
crosses another in the same plane; also called a
crossover fitting. 3. In an auditorium, a passage
which usually parallels the rows of seats, forming
a connection between aisles. 4. At the rear of a
stage in a theater, a passageway that permits an
actor to pass from one side of the stage to the
other side without being seen by the audience.

crossover fitting See crossover, 2.

cross panel A rectangular panel with its longest
dimension in a horizontal direction.

cross passage A passageway across one end of
an open hall, 2 that separates the hall from the
area that serviced the hall.

cross peen hammer A hammer having a
wedge-shaped peen.

cross peen hammer

crosspiece Any piece of timber or beam cross-
ing from wall to wall or running from one part to
another.

cross quarters A cross-shaped ornamental
flower in tracery.

crossrail In a panel door, any horizontal member
other than those at the top and bottom of the door.

cross rib Same as arch rib.

cross riveting Same as staggered riveting.

cross runner In a suspended acoustical ceiling,
a secondary member of the suspension system.
Also see cross-furring.

282

crown

cross seam A seam that is perpendicular to the
long edge of a roll of carpeting.

cross section A representation of a building,
or portion thereof, drawn as if it were cut verti-
cally to show its interior; often taken at right
angles to the longitudinal axis of the building.

cross-sectional area See net cross-sectional
area.

cross-sill A sill, 1 oriented in a direction per-
pendicular to the length of the structure.

cross slit In a medieval fortification, an arrow
loop that has a narrow horizontal opening per-
mitting a soldier to fire his weapon at the enemy.

cross slope Of a surface, the slope that is per-
pendicular to the direction of travel. Compare
with running slope.

cross springer 1 . The diagonal arch of a ribbed
groin vault. 2. A transverse rib of a groined roof.

crosstalk Undesired signals in one electrical
circuit as a result of electrical coupling with
another circuit.

cross tee A light-gauge metal member, similar
in shape to an inverted T; used to support the
abutting ends of form boards in insulating con-
crete roof constructions.

cross tongue A tongue of wood (either cross-
grained or plywood) used to join two timbers
in a tenoned frame to provide additional
strength.

cross valve A valve fitted on a transverse pipe
between two parallel pipes in order to provide
flow between them.

cross vault A vault formed by the intersection
at right angles of two barrel vaults.

cross vault

cross ventilation The circulation of fresh air
through open windows, doors, or other open-
ings, which are in opposite sides of the room or
rooms being ventilated.

crosswalk An area across a street or road esp.
designated for pedestrians by special markings or
paving materials.

cross-wall construction See box frame, 1.

cross welt, transverse seam In flexible-
metal roofing, a seam between sheets; usually
parallel to the gutter or to the ridge.

cross window A window in which the combi-
nation of a single mullion and a transom pre-
sents the appearance of a cross.

cross-wire weld A weld made between crossed
wires or bars.

crotch The point where a tree branch joins the
trunk.

crotchet Obsolete term for crocket.

crotch veneer Wood veneer cut from the
crotch of a tree; often exhibits unusual and dec-
orative grain patterns. Also see curl.

croud Same as crowde.

crowbar, crow A steel bar, one end of which is
flattened; sometimes slightly bent; used for
heavy prying, and as a lever for moving heavy
objects.

crowde A crypt or cellar, especially of a church.

crowfoot 1. Colloquial term for stylolite. 2. A
V-shaped marking on an architectural or engi-
neering drawing, the apex of which indicates a
reference point or the limit of a dimension.

crowfooted Having corbiesteps.

crowfooted gable, crow gable Same as cor-
bie gable.
crow gable See corbie gable.

crown l.Any upper terminal feature in archi-
tecture. 2. The top of an arch including the key-
stone, or of a vault. 3. The corona of a cornice,
sometimes including elements above it. 4. The
camber of a beam. 5. The central area of any

.INLET

CROWN

OUTLET

crown, 9

283

crown course

convex surface. 6. A crown molding. 7. The
high point at the center of a road's cross section.
8. The leafy top of a tree or shrub. 9. In plumb-
ing, that part of a trap where the direction of
flow changes from upward to downward.

crown course A course of curved asbestos
sheet or tile, used to cap the ridge of a roof.

crown glass A handmade glass of soda-lime
composition, used for windows; manufactured in
the early 19th century by a now-obsolete process
in which a hollow sphere of glass was blown
while still very soft, then spun to form a large,
nearly flat circular disk. During the spinning
process, ripple lines were formed in a pattern of
concentric circles, with their center at the cen-
ter of the spun disk; this central area was used in
a bull's eye window. Also see glass.

crowning See crown.

crown molding Any molding serving as a
corona or otherwise forming the crowning or
finishing member of a structure.

crown molding

crown plate 1. Same as bolster. 2. A longitudi-
nal structural member at the apex of a roof that
supports the upper ends of the rafters.

crown post Any vertical member in a roof
truss, esp. a king post.

crown rafter In a hip roof, the central com-
mon rafter.

crown saw, cylinder saw, hole saw A

rotary saw used to cut round holes; has teeth
along the edge of a hollow cylinder.
crown silvered lamp See CS lamp.

crown steeple A decorative termination of a
tower or turret, resembling a crown.

crown tile See ridge tile.

crown under rafter Same as crown rafter.

crown vent In plumbing a vent pipe which is
connected at the crown, 9 of a trap.

VENT

TRAP

waSTE
crown vent

crown weir On the internal surface of a trap
for a plumbing fixture, the highest point of the
bottom surface at the crown, 9.

INLET

:;u-le t

CROWN WEIR

crown weir

crown work A medieval fortified structure
consisting of a central bastion and two demi-
bastions.

crow's-foot Same as crowfoot.

crowsfooting A minor defect in paint whereby
isolated unconnected wrinkles resembling a
bird's foot are formed when a paint film dries.

crowstep See corbiestep.

crowstep gable Same as corbie gable.

crowstone The top horizontal stone of a corbie
gable.

cruciform 1. Cross-shaped. 2. The character-
istic plan for Gothic and other large churches
formed by the intersection of nave, chancel,
and apse with the transepts.

284

crystallized finish

cruciform

cruck One of a pair of naturally curved timbers,
along the outer walls, that support the ridge
beam of a timber-framed house or farm building.

cruck house A medieval house in which the
roof is carried on pairs of naturally curved timbers.

crushed gravel The product resulting from
the artificial crushing of gravel with substan-
tially all fragments having at least one fractured
face. Also see coarse aggregate.

crushed stone, crushed rock The product
resulting from the artificial crushing of rocks,
boulders, or large cobblestones, substantially all
faces of which have been crushed. Also see
coarse aggregate.

crusher-run aggregate Aggregate, 1 that has
been broken in a mechanical crusher and has
not been subjected to any subsequent screening
process.

crusher-run base A base course for asphaltic
or portland cement concrete paving consisting
of crusher-run aggregate.

crushing strength The ultimate strength of a
brittle material (such as concrete) at which dis-
integration by crushing occurs; the greatest com-
pressive stress it can withstand without fracture.

crush plate l.An expendable strip of wood
which is attached to the edge of a concrete form or
to the intersection of fitted forms; used to protect
the form from damage during pulling, prying, or
other stripping operations. 2. A wrecking strip.

crush-room (Brit. ) A foyer.

crutch, cruck One of a pair of naturally
curved timbers that rise from the outer walls to
support the ridge beam, each crutch being called
a blade, 4; joined at the top and connected by
one or two tie beams, the resulting arched frame
forming the unit in the framework of old English
houses or farm buildings; pairs of crutches were
placed at approximately equal intervals.

crutch house, cruck house A medieval
English house in which the roof is carried on
pairs of crutches.

crypt l.A story in a church below or partly
below ground level and under the main floor,
particularly of the chancel, often containing
chapels and sometimes tombs. 2. A hidden sub-
terranean chamber or complex of chambers and
passages.

crypt

cryptocrystalline A rock texture that is too
fine to be discernible with an optical micro-
scope.

cryptoporticus An enclosed gallery with walls
and windows rather than columns, often par-
tially underground for more constant tempera-
ture.

crystal glass A clear glass, made as nearly col-
orless as possible.

crystalline glaze A glaze containing macro-
scopic crystals.

crystallized finish A wrinkled paint finish
caused by fast-drying vehicles containing oils
which have not been gasproofed.

285

crystal palace

crystal palace l.An exhibition building
constructed in large part of iron and glass in
Hyde Park, London for the great exhibition of
1851. 2. Any exhibition building similarly
constructed.

CS l.Abbr. for "caulking seam." 2.Abbr. for
cast stone.

CSA Abbr. for Canadian Standards Association.

C- section A C-shaped cross-sectional configu-
ration; used as a structural framing member.

CSG On drawings, abbr. for casing.
CSI Abbr. for the Construction Specifications
Institute.

CSI division One of the 16 divisions designated
and illustrated under construction documents.

CSK On drawings, abbr. for countersink.

CS lamp An incandescent lamp, the interior of
which is silvered, so that it acts as a reflector,
narrowing the beam of light.

CTB On drawings, abbr. for "cement treated base."

CTD On drawings, abbr. for "coated."

C to C On drawings, abbr. for center- to-center.

CTR On drawings, abbr. for center.

cu Abbr. for "cubic."

cubage The architectural volume of a building;
the sum of the products of (a) the areas and (b)
the height from the underside of the lowest floor
construction system to the average height of the
surface of the finished roof above, for the various
parts of the building.

cubby l.A small closet or storage space.
2. A diminutive room. 3. A small snug hiding
space.

cube strength In a test of the strength of port-
land cement, the load per unit area at which a
concrete cube (of standard size) fails when tested
in a specified manner.

cubical aggregate Angular aggregate most of
whose particles have length, breadth, and thick-
ness approximately equal.

cubicle l.A very small enclosed space. 2. A
carrel.

cubiculum l.In ancient Roman architecture,
a bedchamber. 2. A mortuary chapel attached to
a church. 3. A burial chamber having, on its
walls, compartments for the reception of the
dead.

cubic yard In the US, the customary unit for
measuring the volume of embankments, refuse,
etc.; equivalent to the volume of a cube, each
edge of which measures 3 feet; equals a volume
of 0.765 cubic meters.

cubic yard bank measurement (cybm)

The number of cubic yards of material in its
original place in the ground.
cubic yard compacted measurement

(cycm) The number of cubic yards of exca-
vated material after compaction.
cubiform capital Same as cushion capital.

cubit A linear unit of measurement used by the
ancients; in ancient Egypt, equal to 20.62 in.
(52.4 cm).

cu ft Abbr. for "cubic foot."

cu in. Abbr. for "cubic inch."

cul»de-four A half-dome or quarter-sphere
vault, as over an apse or niche.

cul»de-lampe A pointed, pendant ornament
used at the apex of a vault and to terminate
protruding, elevated structures. Also see drop,
pendant.

cul-de-lampe

cul»de-sac A street, lane, or alley closed at one
end, usually having an enlarged, somewhat cir-
cular area for turning around.

culina In ancient Rome, a kitchen.

cull, brack, wrack A piece of lumber or brick
of a quality below the lowest accepted grade or
below specifications.

cullis See coulisse.

cult temple A temple devoted to the worship
of a divinity, as distinguished from a mortuary
temple.

cultured marble An artificial marble.

culver hole Same as putlog hole.

culvert A passage below ground level which
permits the flow of water; often a large diameter
metal or concrete pipe.

286

curb cock

cu m Abbr. for "cubic meter."
cumar gum A synthetic resin, used in var-
nishes to provide alkali-resistant properties.

Cumberland house A one-story house, pri-
marily found in Tennessee, of the general type
described under folk architecture; usually had a
gable on one or both ends of the house and a
front porch that often served as the center of
family activity.

cumulative batching Measuring more
than one ingredient of a batch of concrete
in the same container by bringing the batcher
scale into balance at successive total weights
as each ingredient is accumulated in the
container.

cuneiform Having a wedge-shaped form; esp.
applied to characters, or to the inscriptions in
such characters, of the ancient Mesopotamians
and Persians.

cuneiform pile A pile which is tapered or

step-tapered.
cunette Around a medieval fort, a dry defensive

ditch in the middle of a narrow moat to improve

its drainage.
cuneus 1 . One of the wedge-shaped sections for

spectators in an ancient theater. 2. Same as

voussoir or wedge.

cuniculus A low underground passage.

cup 1 . The deviation of the face of a board from
a plane. 2. A metal insert in a countersunk screw
hole.

cup base A device to hold a cylindrically
shaped steel column in place at its base.

cupboard An enclosed storage space with
shelves, esp. for dishes, glassware, etc., usually
placed in kitchens or pantries.

cup escutcheon On a sliding door, a plate
which has a recess to provide a fingerhold; con-
tains a flush ring flush with the surface of the
plate.

cup joint A joint between two lead pipes in a
straight line; the tapered end of one is fitted into
the flared end of the other.

cupola 1. A domed roof or ceiling. 2. A domed
structure, often set on a circular or polygonal
base on a roof or set on pillars; often glazed to
provide light in the space below, or louvered to
provide ventilation in that space.

cupola

cup shake A shake occurring between annual
rings; a ring shake.

curb, Brit, kerb 1. A low wall of wood, metal,
or masonry built around an opening in a roof or
placed on the surface of a roof to support equip-
ment. 2. A raised rim of concrete, stone, or
metal which forms the edge of a street, sidewalk,
or planted area. 3. A purlin plate.

curb box, curb-stop box, curb-valve box,
Buffalo box A vertical sleeve which pro-
vides access to a buried curb cock; the cock is
turned by a long key which is inserted through
the sleeve to the cock.

curb cock, curb stop In a water-service pipe,
a control valve for the water supply of a build-
ing, usually placed between the sidewalk and
curb; used to shut off the water supply in case of
emergency.

STOP BOX

CURB COCK
curb cock

287

curb edger

curb edger See curb tool.

curb form A specially shaped form for concrete,
used in conjunction with a curb tool to give the
desired shape and finish to a concrete curb.

curbing 1. Material used for forming curbs. 2.
Slabs and blocks of stone or concrete set on
edge, straight or curved, forming an upward pro-
jection; used as a curb, 2.

curbing machine A machine that extrudes a
continuous strip of asphalt or concrete through a
shaped template as it moves forward.

curb joint, Brit, curb roll, knuckle joint
The horizontal joint that occurs at the intersec-
tion of the two slopes of a curb roof.

curb level 1 . The elevation of the street grade, 2 ,
fixed by municipal authorities. 2. The elevation
at the point of the street grade that is opposite
the center of the wall nearest to, and facing, the
street line. 3. The legally established level of the
curb in front of a building, measured at midpoint
of the line along the front.

curb line The line coincident with the face of
the street curb adjacent to the roadway.

curb plate 1 . The wall plate of a circular or ellip-
tical domical roof, or of a skylight. 2. The plate
which receives the upper rafters of a curb roof.

curb rafter One of the upper rafters of a curb
roof.

curb ramp A short ramp cut through a curb.

curb roll l.Same as curb joint. 2. A wood roll
covered with lead at the intersection of the two
sloped surfaces of a curb roof.

curb roof A pitched roof that slopes away from the
ridge in two successive planes; known as a gambrel
roof in the US and as a mansard roof in Britain.

curb roof

curbstone A stone forming a curb or part of a
curb.

curb stop See curb cock.

curb- stop box See curb box.

curb string, curb stair string Same as close
string.

curb tool, curb edger A tool used to give the
desired finish and shape to the exposed surfaces
of a concrete curb.

curb-valve box See curb box.

curdling The thickening of varnish in a can.

cure l.To change the physical properties of an
adhesive or sealant by chemical reaction, which
may be condensation, polymerization, or vul-
canization; usually accomplished by the action
of heat and catalyst, alone or in combination,
with or without pressure. 2. For concrete, see
curing. 3. To provide conditions conducive to
the hydration process of stucco or portland
cement. 4. To provide a sufficient quantity of
water and to maintain the proper temperature
within a plaster to ensure cement hydration.

curf Same as kerf.

curia The council house in a Roman municipality.

curing Maintaining the humidity and tempera-
ture of freshly placed concrete during some
definite period following placing, casting, or fin-
ishing to assure satisfactory hydration of the
cementitious materials and proper hardening of
the concrete.

curing agent A catalyst; a hardener.

curing blanket A built-up covering of sacks,
matting, burlap, wet earth, sawdust, straw, or
other suitable material placed over freshly fin-
ished concrete; such covering is moistened to
supply water in the early hydration process, and
tends to maintain a uniform temperature.

curing compound A liquid which is sprayed
(or otherwise applied) to newly placed concrete
which retards the loss of water during curing.

curing cycle l.See autoclaving cycle. 2. See
steam-curing cycle.

curing kiln See steam box.

curing membrane A sheet or layer of imper-
vious material laid or sprayed over freshly poured
concrete to restrict evaporation of mixing water
so that the hydration process can be sustained.
Also see membrane curing.

288

curtilage

curing temperature The temperature to
which an adhesive must be subject in order to
ensure that it will cure satisfactorily; usually the
time to effect a satisfactory cure (i.e., the curing
time) is also specified.

curing time The length of time required to
effect the cure of a plastic or resin by chemical
reaction.

curl A winding, swirling, or circling in the grain
of wood, usually obtained from the crotch or fork
of a tree; also see fiddleback.

curling The distortion of a member, originally
linear or planar, so that it is curved in shape, e.g.,
the warping of a slab as a result of temperature
differences.

current The flow of electricity in a circuit; the

unit of measurement is the ampere.
current-carrying capacity The maximum

current which an electric device is rated to carry

without excessive overheating and consequent

premature breakdown or combustion; also see

ampacity.
curstable A course of stones with moldings

cut on them. May be a stringcourse of part of a

cornice.
curtail A short, spiral, scroll-like termination of

any architectural member, as at the end of a stair

rail.

curtailment In reinforced concrete, the bend-
ing of the ends of reinforcing rods to provide
added strength.

curtail plate A plate, 2 that acts as a support for
a gambrel roof where the roof changes pitch.

curtail step A step, usually lowest in a flight of
stairs, having one or both ends rounded in a
scroll shape that projects beyond the newel.
Also called a scroll step.

curtain Same as curtain wall, 2.

curtain board, draft curtain A substantial
noncombustible curtain, hung tightly against
a roof or ceiling along the perimeter of a special-
hazard area; acts as a partition in directing heat
and smoke within the curtained area toward
vents and preventing the spread of fire.

curtain coating The application of paint by
passing the object being coated under a continu-
ous falling sheet of paint.

curtain drain Same as intercepting drain.

curtain grouting The injection of grouting
below the surface, so as to create a mass of grout
which is oriented transverse to the direction of
anticipated water flow.

curtaining Gross sagging of a paint film, such
that a pattern resembling the ruffles on a curtain
is formed. Also see sagging, 3.

curtain line A line on a theater stage, usually
imaginary, where the act curtain touches the
stage floor.

curtain set The set of rigging (lines, arbor,
sheaves, operating line, etc.) associated with a
curtain on a theater stage.

curtain track A horizontal arrangement of
continuous supports for draperies, permitting
the draperies to be drawn along a track.

curtain wall 1. In a tall building of steel-frame
construction, an exterior wall that is non-load-
bearing, having no structural function; also see
metal curtain wall. 2. In ancient fortifications,
an enclosing wall or rampart connecting two
bastions or towers.

curtain wall, 2

curtilage The ground adj acent to a dwelling and
appertaining to it, as a yard, garden, or court.

289

curvature friction

curvature friction The friction resulting

from bends or curves in the specified profile of

posttensioned tendons.
curved muntin A secondary framing member

(i.e., a muntin) that is curved, usually at its

upper end.

curved muntins

cushion capital, 2

cushion frieze A frieze that bulges outward at
its sides, as found in the convex profile of the
frieze in some Classical orders.

curved pediment Same as segmental pedi-
ment.

curvilinear gable Same as multicurved gable.

curvilinear parapet A parapet whose outline
usually consists of a combination of several
curved and straight lines, as, for example, in a
mission parapet.

Curvilinear style The later, richer period of
the Decorated style of English Gothic architec-
ture, in the second half of the 14th cent.

curvilinear tracery See flowing tracery.

cusec A unit equal to one cubic foot per second.

cushion l.A convex element resembling a
pad. 2. A corbel for roofing, a padstone.
3. Padding, as around glass, to reduce the
effects of vibration and abrasion. 4. A piece of
timber acting as a cushion or buffer to resist or
receive the force of another part of the fram-
ing; a cushion piece.

cushion-back carpet A carpet which has a
resilient, cushion-like material that is an inte-
gral part of its backing.

cushion capital l.A capital resembling a
cushion that is pressed down because of weight
on it. 2. In medieval, esp. Norman, architecture,
a cubic capital with its lower angles rounded off.

cushion course l.A convex fascia. Also see
torus. 2. Same as bedding course, 2.

cushioned vinyl flooring Vinyl sheet floor-
ing which has a resilient foam layer incorporated
as part of its thickness.

. frieze

cushion head, Brit, pile helmet A cap which
covers and protects the head of a pile while it is
being driven into the ground by a pile driver.

i head

cushioning Same as carpet underlayment.
cushion piece See cushion, 4.
cushion rafter See auxiliary rafter.

290

cut-off elevation

cushion sand Sand that is used as a bed onto
which a concrete mix is poured.

cusp l.The intersection of two arcs or folia-
tions in a tracery. 2. The figure formed by the
intersection of tracery arcs. Also see foil.

types of cusps

cusped arch See foil arch.

cuspidation A system of ornamentation consist-
ing of or containing cusps, as in a multifoil arch.

custom-built Constructed on the jobsite from
material which was not prefabricated, as distin-
guished from "factory-built."

custom-grade lumber Normal- or middle-
grade lumber, both with respect to material and
quality of workmanship; intended for conven-
tional high-quality work. Compare with econ-
omy-grade lumber and premium-grade lumber.

customhouse A building where customs duties
are received.

custom millwork See architectural millwork.

cut 1. Excavated material. 2. The void resulting
from the excavation of material. 3. The depth to
which material is to be excavated to bring the
surface to a predetermined grade. 4. In the the-
ater, a long slot across the stage floor for the
introduction or removal of scenery.

cut-and-cover A method of laying a pipe (or
constructing a tunnel) by excavating a trench,
then laying the pipe (or constructing the tunnel
lining), and finally covering it with excavated
material.

cut and fill The process of excavating, moving
the excavated material to another location, and
using it as fill, 1.

cut-and-fill line On a site plan, a line that
joins those points that are neither cut (exca-
vated) nor filled (by the placement of additional
material).

cut and fit Same as scribed joint.

cut-and-mitered string An open string of
which the vertical edges of the notches are made
to miter with the ends of the risers.

cut-and-mitered valley A valley which is
close-cut.

cut-and-rubbed brick A brick that is cut to
size and then rubbed to produce the required
finish.

cutaway drawing A pictorial representation
of an object, showing its interior as if a slice of
the object had been removed.

cutback asphalt An organic, bituminous roof
coating or flashing cement in a volatile solvent,
applied without heat; also used for dampproofing
and for priming concrete and masonry surfaces.

cut bracket A bracket-shaped piece of board
(for example, a bracketed string) used either for
support or as a decoration.

cut brick A roughly shaped brick, cut and
trimmed with a bolster.

cut glass A glass which has been decorated by
grinding figures or patterns on its surface by
abrasive means, followed by polishing.

cut line In a theater stage, a rope which can be
cut in case of fire backstage, automatically drop-
ping the asbestos curtain and/or opening the
smoke hatches.

cut nail A nail having a wedge shape, sheared
from sheet steel; has a sheared-square, blunt
point.

cut nails

cutoff 1. The prescribed elevation at which the
top of a drive pile is cut. 2. A structure, such as a
wall, intended to eliminate or reduce percola-
tion through porous strata.

cut-off elevation Of a pile, the elevation of
the top of the pile which is indicated on the con-
tract drawing.

291

cutoff sprinkler

cutoff sprinkler A fire sprinkler whose heads
produce a curtain of water across a door when
a fire alarm system is activated; prevents the
spread of flames.

cutoff stop On a doorframe, a stop which ter-
minates above the floor line and has a closed
end.

cut-off wall A wall, constructed underground,
designed to impede the flow of water.

cutout l.Any opening in a masonry, metal,
grating, or wood surface, as an opening in a
doorframe to receive door hardware. 2. A piece
of material stamped out of sheet metal or other
sheet material. 3. A circuit breaker or valve for
breaking an electrical or piping connection.

cutout box In electric wiring, a metal enclo-
sure that houses circuit breakers or fuses; is
designed for surface mounting, with a swinging
door or cover to provide easy access.

cut pile A carpet having a pile attached to the
carpet backing so that individual strands project
upward by a uniform amount (see carpet pile
height).

cut roof, terrace roof A pitched roof, 1,

which is truncated, forming a flat roof, 1; has no

ridge.

cut splay An oblique cutting of a brick to fit a

slope, a splay, or the like.
cut section Same as cut, 3.

cut stone Building stone cut or machined to a

specified size and shape, each piece fabricated to
conform with drawings, for installation in a des-
ignated location in a finished structure.

cut string, cut stringer Same as open string.

cut size Said of an area of flat glass that has
been cut from a manufactured sheet to fit in a
prepared opening.

cut stock Softwood stock that has been
processed at the mill so that maximum waste is
left at the mill.

cutter, rubber A soft brick, sometimes used for
facework because of the facility with which it
can be cut or rubbed down.

cutting A short piece of lumber resulting from
crosscutting or ripping operations.

cutting and waste See circular cutting and
waste.

cutting gauge A tool with an adjustable stop
similar to a marking gauge but with a cutting
blade instead of a marking pin; used for cutting
veneer and thin wood.

cutting in Careful use of a brush to paint the
edge of a corner wall, ceiling area, door, or win-
dow frame.

cutting list A tabulation of the dimensions of
wooden pieces or timbers required for a particu-
lar job.

cutting pliers Pliers with jaws having sharp
edges esp. adapted for cutting wire.

cutting screed A tool with a sharp edge; used
for trimming shotcrete to a finished outline.

cutting stock In stone milling, slabs of suitable
size and thickness from which cut stone units are
fabricated.

cutting torch A device used in oxygen, air, or
powder cutting for controlling and directing the
gases used for preheating and the oxygen or pow-
der used for cutting the metal.

cutting waste The waste of materials that
occurs as a result of the difference in size between
that which is required for a construction job and
that which is usually commercially available.

cut-work See gingerbread.

cu yd Abbr. for "cubic yard."

CV Symbol for swing check valve.

CV1S Abbr. for "center vee one side."

CV2S Abbr. for "center vee two sides."

CW l.On drawings, abbr. for "cold water." 2.
On drawings, abbr. for "clockwise." 3. Abbr. for
"cool white."

C/W Abbr. for clerk of the works.

cwt Abbr. for "hundred weight."

CWX Abbr. for "cool white deluxe."

cybm Abbr. for cubic yard bank measurement.

cycle See alternating current.

cycles per second A unit of frequency.

cycloid A curve generated by a point in the
plane of a circle when the circle is rolled along a
straight line, keeping always in the same plane.

cycloidal arch An arch whose intrados forms a
cycloid.

cyclone cellar A covered area below grade; a
place of refuge from dangerous windstorms. Also
called a storm cellar.

292

cyma reversa

cyclone collector A conical sheet-metal
device for separating and collecting particles
from the air by centrifugal force; used in exhaust
systems, esp. in factories.

Cyclopean 1. Describing prehistoric masonry,
made of huge stone blocks laid without mortar.
2. Megalithic.

Cyclopean, 1 wall

includes the keyhole but is separated from the
lock case.

cylinder saw See crown saw.

cylinder screw In a lock mechanism the
setscrew that prevents the cylinder from being
turned after installation.

cylinder strength Of concrete, same as com-
pressive strength.

cylinder test A test to determine the compres-
sive strength of concrete by subjecting a con-
crete test cylinder to compression.

cylinder wrench Same as pipe wrench.

cylindrical barn Same as circular barn.

cylindrical lock A bored lock which has a
cylindrical case into which a separate latchbolt
case fits.

cyclopean concrete Mass concrete in which
large stones, each of 100 lb (45.4 kg) or more,
are placed and embedded as the concrete is
deposited; such a stone is called a pudding
stone or plum; they are usually not less than 6
in. (15 cm) apart and not closer than 8 in. (20
cm) to any exposed surface. Also see rubble
concrete.

cyclorama A curved backdrop at the rear of a
theater stage, sometimes extending around to
the proscenium arch in a U-shape; usually
painted to simulate the sky.

cyclostyle A circular colonnade which is open
at the center.

cyan Abbr. for cubic yard compacted measure-
ment.

cylinder In a lock, the cylindrically shaped
assembly containing the tumbler mechanism
and the keyway, which can be actuated only by
the correct keys.

cylinder collar A plate or ring used under the
head of the cylinder for a lock.

cylinder glass In the past, a type of relatively
poor-quality glass made by blowing a cylinder
of molten glass, dividing it lengthwise, and
then rolling these sheets flat while the glass
was still hot; much cheaper than the higher-
quality crown glass then available; also called
sheet glass.

cylinder lock A door lock in which the lock-
ing mechanism is contained in a cylinder that

PIN-TUMBLER
OR DISK
TUMBLER
CYLINDER

BOLT ATTACHES
TO EITHER SIDE

cylindrical lock

cylindrical stair Same as spiral stair.

cylindrical vault A barrel vault.

CYL L On drawings, abbr. for cylinder lock.

cyma, cima A molding having a profile of dou-
ble curvature; one having an ogee profile.

cyma recta, Doric cyma A molding of dou-
ble curvature which is concave at the outer edge
and convex at the inner edge.

cyma reversa, Lesbian cyma A molding of
double curvature which is convex at the outer
edge and concave at the inner edge.

cyma recta

cyma reversa

293

cymatium

cymatium The crowning molding of a classical
cornice, esp. when it has the form of a cyma,
though it may also be an ovolo or cavetto; an ogee.

cymbia See cimbia.

cypress A moderately strong, hard, and heavy
softwood of the US; its heartwood is naturally
decay-resistant and is used for exterior and inte-
rior construction where durability is required.

cyrtostyle A projecting curved portico, usually
semicircular, having columns.

cymatium

294

d Abbr. for penny (nail size).

D Abbr. for "down."

D&CM Abbr. for "dressed and center

matched."
D&H In the lumber industry, abbr. for "dressed

and headed."
D&M In the lumber industry, abbr. for "dressed

and matched."
D&MB Abbr. for "dressed and matched beaded."
D&SM Abbr. for "dressed and standard

matched."
D1S Abbr. for "dressed one side."
D2S Abbr. for "dressed two sides."
D2S&CM Abbr. for "dressed two sides and

center matched."
D2S&M Abbr. for "dressed two sides and

matched."
D2S&SM Abbr. for "dressed two sides and

standard matched."
D4S Abbr. for "dressed on four sides."
dabber A soft brush used to apply varnishes.
dabbing, daubing Dressing a stone surface

with a special pointed tool to produce a pitted

appearance.
DAD On drawings, abbr. for double-acting door.
dado l.The middle portion of a pedestal

between the base (or the plinth) and the sur-

base (or the cornice, cap, or entablement); also

called die. 2. The middle part (sometimes all

parts) of a protective, ornamental paneling

applied to the lower walls of a room above the

baseboard. 3. A rectangular groove cut across
the full width of a piece of wood to receive the
end of another piece.

dado cap A chair rail or cornice at the top of a
dado.

dado groove Same as dado, 3.

dado head A power-driven rotary cutter, usu-
ally consisting of two identical circular saws with
a chipper between them; used in woodworking
for cutting flat-bottomed grooves.

dado joint See housed joint.

dado rail A chair rail.

dagger A small decorated tracery motif in the
form of a distorted cusped lancet, with the foot
pointed; a pointed oval-shaped opening in the
tracery.

dagoba In Buddhist architecture, a monumen-
tal structure containing relics of Buddha or of
some Buddhist saint.

dado, 3

dagoba in Sri Lanka

daily noise dose See noise dose.
dairy See milk house.

dais A raised platform reserved for the seating
of speakers or dignitaries. (See illustration
p. 296.)

295

dalan

DAMPER

dais

dalan In Persian and Indian architecture, a
veranda, or sometimes a more stately reception
hall, more or less open to the weather, with a
roof carried on columns, or the like.

dallan Same as dalan.

dalle A slab or large tile of stone, baked clay,
etc., esp. a tile of which the surface is incised or
otherwise ornamented, such as the medieval
sepulchral slabs set in the pavement and walls of
churches.

damages See liquidated damages.

dammar, damar, dammer, gum dammar
A naturally occurring resin; useful in paints and
varnishes because of its light color.

damp check See damp course.

damp course, damp check, dampproof
course In masonry, an impervious horizontal
layer of material (as tile, dense limestone,
metal, etc.) to prevent the capillary entrance of
moisture from the ground or a lower course, but
used also below copings, above roof level in
chimneys, and elsewhere to stop downward
seepage.

damper 1 . A device used to vary the volume of
air passing through an air outlet, inlet, or duct; it
does not significantly affect the shape of the
delivery pattern. 2. A pivoted cast-iron plate at
fireplace throat, i.e., between fireplace and
smoke chamber, to regulate draft. 3. Same as
fireplace damper.

damper, 1

butterfly damper, 1

damping The dissipation of energy with time,
e.g., the dissipation of energy in a mechanical
system whose free oscillations decrease with
time, resulting in a decrease in its amplitude of
vibration.

damping material A viscous material applied
to a vibrating surface, such as a metal panel, to
reduce the noise which it radiates.

dampproof course See damp course.

dampproofing l.A treatment of concrete or
mortar to retard the passage or absorption of
water, or water vapor, either by applying a suitable

GRAVEL

51 1 I Dine
PAPER
PMJjfNGWITH DRAIN TILE

dampproofing, 3

296

davit

coating to exposed surfaces or by using a suitable
admixture. 2. A damp course. 3. Applying a
water-impervious material to a surface, such as a
wall, to prevent the penetration of moisture.

damp-proof membrane See membrane
waterproofing.

dancers Colloquial term for stairs.

dancette See chevron, 2; also see zigzag.

dancing step, danced step See balanced
step.

dancing winder See balanced step.

Danish knot Same as Runic knot.

dao, paldao A variegated colored wood from
the Philippines and New Guinea, having shades
of gray, green, yellow, brown, and pink with dark
streaks; moderately hard, heavy; used for cabi-
nets, plywood, and interior finish.

dap A notch in a timber for receiving another
timber or into which the head of a pile is fitted.

dapped beam Said of a beam (or girder) hav-
ing a notch to receive another notched beam.

dar 1 . In Indian and Persian architecture, a gate-
way. 2. In Oriental architecture, a dwelling.

darby, derby slicker 1. A float tool used in
plastering, either wood or metal, about 4 in.
(10 cm) wide and about 42 in. (approx. 1 m)
long, with two handles; used to float or level
the plaster base coat prior to application of
the finish coat, or to level the plaster finish
coat before floating or troweling. 2. A hand-
manipulated straightedge usually 3 to 8 ft ( 1 to
2.5 m) long, used in the early-stage leveling
operations of concrete finishing to supplement
floating.

dart See egg-and-dart molding; anchor, 8.

dash-bond coat A thick slurry of portland
cement, sand, and water dashed on surfaces with
a paddle or brush to provide a base for a subse-
quent plaster coat.

dashed finish An exterior wall finish,
obtained by throwing small pebbles against a
smooth mixture of cement while it is still wet.
Also see rock dash.

date of agreement The date stated on the
face of the agreement. If no date is stated, it may
be the date on which the agreement is actually
signed, if this is recorded, or it may be the date

established by the award; also referred to as the
contract date.
date of commencement of the work The

date established in a notice to proceed or, in the
absence of such notice, the date of the agree-
ment or such other date as may be established
therein or by the parties thereto.

date of substantial completion The date
certified by the architect when the work, 1 or a
designated portion thereof is sufficiently com-
plete, in accordance with the contract docu-
ments, so the owner may occupy the work or
designated portion thereof for the use for which
it is intended.

date stone A stone, imbedded in the walls of
many old buildings, carved with the date of com-
pletion of the structure.

date stone

datum A level surface or point to which other
levels are related; a reference in measuring
elevations.

datum dimension A dimension that exactly
locates a reference point, reference line, or refer-
ence plane.

datum line Same as reference line.

datum point In surveying, the point to which
all other points are related.

daub 1. A material such as clay, mortar, mud, or
plaster (often mixed with straw), used as infilling
between logs, as a coating over walls, or as plas-
ter in wattle-and-daub. 2. To coat roughly with
plaster or mud.

daubing l.See dabbing. 2. A rough coating of
plaster given to a wall by throwing plaster
against it.

davit A movable crane, 1 that projects over the
side of a building.

297

day

day One division in a window, as in a large
church window.

day gate In a bank, an interior grille door to a
safe-deposit vault; used when the main vault
door is open.

daylight factor The ratio of the illumination
at a point on a given plane to the illumination
on a horizontal plane from the whole of an
unobstructed sky of assumed or known lumi-
nance distribution; a measure of the daylight
illumination at that point.

daylight glass A bluish glass, often colored
with cobalt, used with incandescent lamps to
produce the effect of daylight by absorbing excess
radiation in the red part of the light spectrum.

daylighting Lighting of the interior of a build-
ing by natural means; for example, by windows
or skylights.

daylight lamp 1. Any type of lamp which pro-
duces light whose spectral distribution approxi-
mates that of a specified daylight condition. 2.
See incandescent daylight lamp.

daylight saturation level Said of the condi-
tion where the illumination provided by day-
light equals or exceeds the illumination
provided by artificial lighting.

daylight width, sight size, sight width The
width of a glazed opening which admits light.

dB Abbr. for decibel.

dB(A) A unit of sound-level; a reading taken
on the A-scale of a sound-level meter.

DB. Clg. Abbr. for "double-headed ceiling."
DBL On drawings, abbr. for "double."
DBT Abbr. for dry-bulb temperature.
dc, d-c, d.c., DC Abbr. for "direct current."
D-crack, D-line crack l.In concrete sur-
faces, one of many fine, closely spaced cracks;
often in random patterns. 2. In highway slabs,
one of the fine cracks parallel to the edges,
joints, and larger cracks or cutting diagonally
across the corners.
DD On drawings, abbr. for Dutch door.
deactivation The reduction or removal of
the corrosive qualities of water, usually by pass-
ing the water through a deactivator while hot.
deactivator A tank containing iron filings
which removes active oxygen and other corro-
sive elements from water that passes through it.

dead Descriptive of electric wiring which is not

connected to a source of voltage.
dead-air space Unventilated air space within

a structure, as in a shaft, ceiling, or hollow wall.
dead bolt A type of door lock; the bolt, which

is square in cross section, is operated by the door

key or a turn piece.

dead bolt

dead-burnt gypsum See anhydrous calcium

sulfate.
dead door Same as blank door.

dead end 1 . A length of pipe leading from a
soil, waste, or vent pipe, building drain, or build-
ing sewer, which is terminated by a plug, cap, or
other closed fitting; there is no circulation in
this length of pipe, and no waste from a plumb-
ing fixture is fed into it. 2. The point of fastening
in a running rope system where the other end is
fastened to a rope drum. 3. In concrete work,
the end opposite that to which a load is applied.
4. A portion of a corridor in which the travel to
an exit is in one direction only.

dead-end anchorage Anchorage at the end
of a tendon which is opposite the jacking end.

deadening The use of damping material.

dead flue A flue that has been bricked-up or
otherwise sealed off.

dead-front Descriptive of a piece of electric
equipment so constructed that there are no parts
which can be touched from the front of the
assembly that are at a voltage different from that
of the earth.

dead knot A knot that has lost its fibrous con-
nection with the surrounding wood; it can easily
loosen and fall out or be knocked out.

deadlatch Same as night latch.

dead leaf Same as standing leaf.

298

decastyle

dead leg Same as dead end.

dead level Said of a roof surface having a decli-
nation of less than 2%.

deadlight See fixed light.

dead load l.The weight of a structure itself,
including the weight of fixtures or equipment
permanently attached to it. Compare with live
load. 2. The load imposed on a pipe located in a
trench and covered by infill; depends on the
depth and width of the trench, and the density
and character of the infill material.

deadlock 1. A lock equipped with a dead bolt
only. 2. A lock in which a bolt is moved by
means of a key or thumb turn, and is positively
stopped in its projected position.

deadlocking latch bolt See auxiliary dead
latch.

deadman A buried concrete block, log, plate,
or the like, which serves as an anchorage, e.g., as
an anchor for a tie to a retaining wall; depends
on its own weight and passive pressure from the
soil to hold it in place.

dead man anchor Same as guy anchor.

dead parking Long-term, unattended storage
of a vehicle.

dead-piled Descriptive of lumber or panels
stacked without spacers.

dead room A room characterized by an unusu-
ally large amount of sound absorption.

dead sand Sand that may be used as an under-
neath course for a finished layer of loose stones
or gravel.

dead shore An upright piece of heavy timber
used as a prop or support for a dead load during
structural alterations to a building, esp. one of
two supports for a needle, 1 .

dead-soft temper The temper of sheet copper
used for roofing.

dead 'wall A wall whose entire surface is unbro-
ken by a door, window, or any other opening; a
blank wall.

dead weight See dead load.

dead window Same as blank window.

deadwood l.Dead tree limbs or branches. 2.
Wood from dead trees.

deal 1. (L7S) Pine or fir lumber cut to a specified
size, usually at least 3 in. (76 mm) thick and 9 in.
(229 mm) wide. 2. (Brit.) Square-sawn softwood

lumber, l%in. (47.6 mm) to 4 in. (101.6 mm)
thick and 9 in. (228.6 mm) to under 1 1 in.
(279.4 mm) wide.

dealbatus A coating of white cement or stucco
(albarium opus), employed extensively by the
ancient Romans as an ornamental facing to con-
ceal rough stones or brickwork.

deambulatory l.An aisle extending around
the apse of a church; an apse aisle. 2. The ambu-
latory of a cloister, or the like.

deambulatory, 1

de-bonding In pretensioned construction, a
procedure used to prevent specific tendons from
becoming bonded to the concrete for a specified
distance from the ends of the flexural members.

debt service The periodic repayment of a loan,
including both accrued interest and a portion of
the principal.

DEC On drawings, abbr. for "decimal."

decal, decalcomania Colored designs on
special paper for transfer to unglazed or glazed
ceramic ware or glass.

decani side The south side of a church, i.e., the
side on the right of one facing the altar.

decarburization The loss of carbon at the sur-
face of carbon steel when it is heated for process-
ing or in modifying its mechanical properties.

decastyle A building having a portico of ten
columns, or rows of ten columns.

decastyle

299

decatetrastyle

decatetrastyle Said of a Classical building por-
tico having fourteen columns in the front or end
row.

decay See brown rot, white rot.

decayed knot See unsound knot.

decay rate 1. At a given frequency, the rate at

which the sound level in a room decreases after
a source stops emitting sound; expressed in deci-
bels per second (dB/s). 2. Of sound waves in an
enclosed space, the rate at which the sound-
pressure level of reverberation decreases; usually
expressed in decibels per second. 3. Of a vibrat-
ing mechanical system, the rate at which some
stated characteristic (such as the amplitude of
vibration) decreases with time.

decenter To remove centering or shoring.

decibel The unit in which the level, 4 of various
acoustical quantities is expressed.

deciduous Descriptive of trees or shrubs, usu-
ally of temperate climates, that shed their leaves
annually; characteristic of most hardwoods and a
few softwoods.

deck 1 . The flooring of a building or other
structure. 2. A flat open platform, as on a roof. 3.
The structural surface to which a roof covering
system is applied. 4. The top section of a
mansard or curb roof when it is nearly flat.

deck clip l.A metal fastening device used to
attach roof-deck material to a structural frame.
2. An H-shaped metal piece used between adja-
cent sheets of plywood decking to limit uneven
deflections. 3. Any device used to fasten thermal
insulation to a roof-deck.

deck curb A curb around the edge of a roof-
deck.

deck dormer A hipped dormer that has been
truncated so that it has a flat, horizontal roof.

deck drain A drain that is similar in all
respects to a roof drain except that it generally
has a flat strainer and is located in a flat area
such as a patio, walkway, etc.

decking l.The thick boards or planks used as
structure flooring, usually for long spans
between joists or for heavy service; also called
planking. 2. Light-gauge sheets of metal which
are ribbed, fluted, or otherwise integrally stiff-
ened for use in constructing a floor or roof. 3.
See roof decking.

deck»on»hip A flat roof capping a lower roof
that is hipped.

deck paint An enamel having a high degree of
resistance to mechanical wear; esp. used on sur-
faces such as porch floors.

deck roof, deck-on-hip roof A hipped roof

that has been truncated to form a flat-topped
roof.

deck screens Two or more screens, 3 placed
one over the other.

Deconstructivist architecture Architec-
ture that seeks to arrive at new forms of expres-
sion by turning away from structural restraints
and functional and thematic hierarchies, and
toward often nonrectangular, fantastic, and
seemingly disjointed designs. Such work often
represents an application of the philosophical
theories of Jacques Derrida in France, who
sought to arrive at new insights in literature by
breaking apart literary texts into their contradic-
tory and hidden components of meaning; this
philosophy has been applied in the late 20th
century to architectural structures usually called
deconstructivist architecture.

decor The combination of materials, furnish-
ings, and objects used in interior decorating to
create an atmosphere or style.

Decorated style The second of the three
phases of English Gothic architecture, from ca.
1280 to after 1350, preceded by Early English
style and followed by the Perpendicular style;
characterized by rich decoration and tracery,
multiple ribs and liernes, and often ogee arches.
Its early development is called Geometric; its
later, Curvilinear.

300

deferred maintenance

Decorated style

decorative block A concrete masonry unit
having special treatment of its exposed face
shell for architectural effect; such treatment
may consist of distinctive aggregates (with or
without additional coloring) or of beveled
recesses (for patterned appearance when illu-
minated obliquely).

decorative half-timbering Timbers or boards
that provide the appearance of half-timbered
construction but whose function is ornamental
rather than structural; also called false half-
timbering.

decorative paint A paint which conceals the
covered surface and provides a decorative and
protective coating.

decorative stone Stone that functions as
architectural decoration.

decoupling The separating of building ele-
ments to reduce the transfer of heat, sound, or
physical loads from one element to another.

dedicated street A street, the title of which
has been yielded by an owner, either perma-
nently or temporarily, to the authorities for use
of the street by the general public.

dedication cross A cross painted or carved on
the wall of a church to indicate any one of the
twelve spots touched with chrism by the bishop
at the consecration ceremony of the church.

deductible On a building project, a type of insur-
ance policy stipulating that in the event of loss, the
insured is liable for a specified initial amount and
the insurance company is liable for the amount
above that figure, up to the insured amount.

deduction The amount deducted from the
contract sum by a change order.

deductive alternate An alternate bid result-
ing in a deduction from the same bidder's base
bid. Also see alternate bid.

deed Any duly attested, written document exe-
cuted under seal and delivered to effect a trans-
fer, bond, or contract, such as a conveyance of
real property or interest therein.

deed restriction A limitation on the use of
land, which is set forth in a deed conveying the
restriction.

deep bead See draft bead.

deep beam footing A tie beam, 2 for carrying
heavy loads; resists shear forces.

deep cutting, deeping The resawing of tim-
ber lengthwise, parallel to the faces.

deep foundation A continuous foundation
which provides a footing by filling a deep trench
with concrete.

deeping See deep cutting.

deep-seal trap, antisiphon trap In plumb-
ing, a U-shaped trap having a seal, 3 of 4 in. ( 10
cm) or more.

deep well A well that draws water from
beneath an impermeable stratum.

default A substantive failure to fulfill a material
obligation under a building contract.

defect In wood, a fault that may reduce its dura-
bility, usefulness, or strength.

defective work Work not complying with the
contract requirements. See nonconforming work.

deferred maintenance The postponement of
maintenance for any reason, such as the need to
keep equipment in full-time operation, the lack

301

deferrization

of funds for repair, or the unavailability of
parts.

deferrization The treatment of water to remove
soluble compounds of iron.

deficiencies See defective work.

deflagration Burning; the rapid combustion of
a substance, attended with an extremely sudden
evolution of flame and vapor.

deflected shape Said of the profile of a struc-
ture that is deformed when it is loaded.

deflected tendons In a concrete member, ten-
dons which have a curved trajectory with
respect to the gravity axis of the member.

deflection 1 . Any displacement in a body from
its static position, or from an established direc-
tion or plane, as a result of forces acting on the
body. 2. The deformation of a structural member
as a result of loads acting on it.

deflection angle In surveying, a horizontal
angle measured from prolongation of the preced-
ing transit line to the next line; recorded as
"right" if clockwise rotation and "left" if coun-
terclockwise.

deflection limitation The maximum deflec-
tion permitted by code or by good practice.

deflectometer A device for measuring the
amount of bending in a beam induced by a trans-
verse load.

deformation Any change of form, shape, or
dimensions produced in a body by a stress or force,
without a breach of the continuity of its parts.

deformed bar, deformed reinforcing bar
A steel reinforcing bar which is manufactured

deformed bars

with surface deformations to provide a locking
anchorage with surrounding concrete.

deformed metal plate A corrugated (or other-
wise deformed) metal plate used in construction
to form a vertical joint and to provide a mechan-
ical interlock between the adjacent sections.

deformed reinforcement In reinforced con-
crete, reinforcement, 1 consisting of reinforcing
bars, reinforcing rods, deformed wire, welded
wire fabric, and welded deformed wire fabric.

deformed tie bar A deformed bar used as a tie
bar to hold two slab elements in close contact.

defrosting The removal of accumulated ice
from a cooling element.

defurring Same as deliming.

DEG On drawings, abbr. for "degree."

degradation Disintegration of a paint film by
heat, moisture, sunlight, or natural causes.

degrades Pieces of lumber which, during rein-
spection, prove to be of lower quality than origi-
nally classified.

degree 1. A step, as of a stair. 2. A stair, or set of
steps.

degree»day A unit used in estimating the fuel
consumption for a building; equal to the num-
ber of degrees that the mean temperature, for a
24-hour day, is below the "base temperature";
the base temperature is taken as 65°F (18.3°C)
in the US and as 60°F (15.6°C) in Great
Britain.

degree of compaction A measure of the
packing of soil. Also see voids, 2.

degree of saturation Same as percent satura-
tion.

dehumidification l.The condensation of
water vapor from air by cooling below the dew
point. 2. The removal of water vapor from air by
chemical or physical methods.

dehumidifier Any device or apparatus for
removing moisture from air.

dehydration The removal of water vapor from
air by the use of absorbing or adsorbing materials.

deionization See cation-exchange softening.

DEL On drawings, abbr. for "delineation."

delamination A failure in a laminated struc-
ture characterized by the separation or loss of
adhesion between plies, as in built-up roofing or
glue-laminated timber.

302

demountable partition

delay cap A blasting cap that explodes (as the
result of an electrical current through it) at a set
time after activation.

deletion A change order that reduces the scope
of work originally defined in the contract docu-
ments.

deliming The removal of scale, 8 on the inside
of boilers or hot water heaters.

deliming tee A tee, 2 provided at the entry and
outlet of a water heater to permit the temporary
installation of deliming equipment periodically.

deliquescence The absorption of water from
the air by certain salts in plaster or brick; results
in dark, damp areas on the surface.

delivery hose A hose through which fresh
concrete, mortar, or the like is pumped.

delivery point See point of service.

delphinorum columnae The two columns at
one end of the spina of an ancient Roman circus,
on which marble figures of dolphins were placed.

delta connection A connection arrangement
of a three-phase electrical transformer; the three
windings are connected in series forming a
closed circuit in the shape of a Greek capital
delta. Compare with wye connection.

delta connection

delubrum 1. In ancient Roman architecture, a
sanctuary or temple. 2. The part of a classical
temple containing the altar or a statue of the
deity; the most sacred part of the temple.

deluge sprinkler system 1 . A dry-pipe sprin-
kler system with open heads; is controlled by an
automatic valve which is activated by smoke- or
heat-sensitive devices; provides a dense, uniform
coverage of water over the protected area. 2. A
fire sprinkler system using open sprinklers (i.e.,
open sprinkler heads). When the fire detection
system is activated, the deluge valve opens,
resulting in water being sprayed simultaneously
from all of the open sprinklers; usually used for
protection against rapidly spreading high-hazard
fires.

deluge valve A special valve that, under nor-
mal conditions, holds back the water from the
piping of a deluge sprinkler system; a separate
fire detection system is used to open this valve.

DEL V symbol for deluge valve.

demand 1 . The electric load on a system, inte-
grated over a specific time interval; usually
expressed in watts or kilowatts. 2. The volume of
gas per unit time (usually expressed in cubic feet
per hour or liters per second) or the amount of
heat (usually expressed in Btu per hour or mega-
joules per hour) required for the operation of
one or more gas appliances. 3. The rate of flow of
water, usually expressed in gallons per minute
(liters per second), furnished by a water supply
system to various types of plumbing fixtures and
water outlets under normal conditions.

demand factor The ratio of the maximum
demand of a system to the total connected load
of the system.

demand mortgage loan A call loan which is
secured by a mortgage.

demand surcharge An additional charge
imposed by an electrical utility for electricity
used during periods of peak demand.

demesne All lands belonging to the lord of a
manor.

demi-bastion In military architecture, a bas-
tion constructed of one face, 1 and one flank.
Also called a half-bastion.

demi-berceau A half tunnel-vault.

demicolumn Same as half column.

demilune Same as ravelin.

demimetope A half, or incomplete, metope in
a Doric Frieze.

demi-relief, demi-relievo Same as mezzo-
relievo.

demising wall Any wall that separates one
tenant's space from that of another tenant.

demographic study A study of the size, distri-
bution, and composition of, and changes within,
a specified population group.

demolition The systematic destruction of a
building, all or in part.

demountable partition, relocatable parti-
tion A nonload-bearing partition of dry
construction, assembled from prefabricated
components, which can be installed, removed,

303

demurrage

dentil One of a band of small, square, toothlike
blocks forming part of the characteristic orna-
mentation of the Ionic, Corinthian, and Com-
posite orders, and sometimes the Doric.

demountable partitions

and then reinstalled at a different location; may
be full height, from floor to ceiling, or partial
height.

demurrage A charge made by shippers for the
time exceeding that normally allowed for load-
ing and/or unloading of building components
or materials delivered by railroad, truck, or
ship.

den An indoor retreat, usually small, for work or
leisure. Also see chamber, 1.

dendrochronology The dating of old timbers
by the study of their annual ring patterns of
growth.

dendrology The branch of botany involving
the study of trees and shrubs.

dense concrete Concrete containing a mini-
mum of voids.

dense-graded aggregate An aggregate graded
to produce low void content and maximum
weight when compacted.

densified impregnated wood See com-
pressed wood.

density The degree of aggregation; the quantity
of any entity distributed over an area per unit of
areal measure, e.g., persons per acre, families per
acre, or dwelling units per square mile.

density control The control of the density of
concrete in field construction to ensure that
specified values, as determined by standard tests,
are obtained.

density rules Methods that estimate the den-
sity of wood based on the amount of summer-
wood and its rate of growth.

denticulated, denticular Ornamented with
dentils.

Ionic dentils

dentil band l.A molding that occupies the
position of a row of dentils in classical architec-
ture. 2. A course of masonry that resembles a
row of dentils; for example, in brickwork, the
toothlike effect produced by the projection of
alternate headers and smaller blocks.

Department of Housing and Urban
Development (HUD) An agency of the
US government that administers provisions of
the various housing acts that have been passed
by Congress.

dependency A subsidiary building near or
adjoining a principal structure.

depeter Same as depreter.

depolished glass Any glass having a diffuse
surface, usually produced by etching, sandblast-
ing, etc.

deposited metal The filler metal that is added
during a welding operation.

deposit for bidding documents Monetary
deposit required to obtain a set of construction
documents and bidding requirements, customar-
ily refunded to bona fide bidders on return of the
documents in good condition within a specified
time.

depository See bank depository.

304

design documents

depot l.A place of deposit; a storehouse or
warehouse. 2. A railroad station; a building for
the accommodation and shelter of passengers
and the receipt and transfer of freight by the
railroad.

depreciation factor The reciprocal of mainte-
nance factor.

depressed arch A drop arch.

depression storage The quantity of storm
water that is lost as a result of minor surface
depressions in the ground.

depreter Stucco with a rock dash finish.

DEPT On drawings, abbr. for "department."

depth gauge A device for measuring the depth
of a hole, cutout, groove, recess, etc.; usually con-
sists of a graduated scale which slides through a
crosspiece.

(

FLAT
BASE

vij /-

■3

•SLIDING
HEAD

depth gauge

depth of fixity The depth below ground level
at which the soil firmly holds a pile.

derating The reduction in the normal rating of
equipment to account for abnormal environ-
mental conditions to which the equipment may
be subject.

derby, derby float See darby.

derrick One of a number of types of hoisting
devices, equipped with tackle at their upper ends,
that lift building materials at a construction site.

desague In Hispanic architecture, a drainage
channel on a wall that discharges rainwater
down the side of a building.

descaling Removing scale, 8 that forms on the
inside of hot water heaters, boilers, etc.

descriptive specification A specification
that provides a written description of the mate-
rials, equipment, construction systems, and level
of workmanship required on a job. Compare
with prescriptive specification and performance
specification.

desiccant Any absorbent or adsorbent, liquid
or solid, that will remove water or water vapor
from a material. In a refrigeration circuit, the
desiccant should be insoluble in the refriger-
ant.

desiccation l.The use of a desiccant for dry-
ing. 2. The use of heated air to remove moisture,
as from timber in a kiln.

design l.To compose a plan for a building.
2. The architectural concept of a building as
represented by plans, elevations, renderings,
and other drawings. 3. Any visual concept of a
man-made object, as of a work of art or a
machine.

designated services On a building project,
those services that the architect, engineers, and
consultants agree to perform.

design/build A construction project in which
the owner contracts with a single entity to be
responsible for both design and construction.

design class A classification rating that indi-
cates the level of resistance to fatigue of a build-
ing component.

design development phase The second
phase of the architect's basic services. In this
phase the architect prepares (from the
approved schematic design studies, for approval
by the owner) the design development docu-
ments consisting of drawings and other docu-
ments to fix and describe the size and
character of the entire project as to structural,
mechanical and electrical systems, materials
and such other essentials as may be appropri-
ate; the architect also submits to the owner a
further statement of probable construction
cost.

design documents See structural design doc-
uments.

305

design life

design life The period of time over which a
building component or structure is required to
perform safely, with an acceptable probability
that it will not require replacement or signifi-
cant repair during that time.

design load l.The total load on a structural
system for the worst combination of loads and
forces which it is designed to sustain. 2. In an
air-conditioning system, the maximum heat load
which it is designed to handle. 3. See design ulti-
mate load.

design occupancy The number of people
and/or activities for which an environmental
system has been designed.

design phase An early phase of work on a
building project in which the design of the proj-
ect is laid out; usually followed by the construc-
tion phase.

design population On a public works project,
the maximum number of people for whom the
project is designed.

design professional An architect or engineer,
or both, duly licensed for professional practice,
who may be employed by an owner for the pur-
pose of designing a project.

design strength l.The load-bearing capacity
of a member computed on the basis of the
allowable stresses which are assumed in design.
2. The assumed values for the strength of con-
crete, and the yield stress of steel on which the
theoretical ultimate strength of a section is
computed.

design ultimate load, factored load In

structural design, the working load times the
load factor.

desornamentado Said of architecture of 1 6th-
century Spanish Renaissance architecture that is
relatively simple.

de Stijl An architectural movement from about
1917 to 1931, which originated in The Nether-
lands, that placed emphasis on functionalism,
rationalism, and current methods of construction,
in contrast to historical precedent and traditional
methods of construction. This movement had a
significant influence on the development of Mod-
ern architecture.

destina 1. A pillar or other support for a build-
ing. 2. An aisle or small cell in a church.

destraria A late Latin term for deambulatory.

DET l.On drawings, abbr. for detail. 2. On
drawings, abbr. for "detached." 3. Abbr. for
"double end trimmed."

detached garage l.A garage which is com-
pletely surrounded by open space. 2. A garage
connected to a building by an uncovered terrace.

detached house A house that stands completely
alone, not sharing a wall with another house.

detail 1 . A minor section of an architectural
design or concept. 2. A drawing, at a larger
scale, of a part of another drawing, indicating
in detail the design, location, composition, and
correlation of the elements and materials
shown.

detail drawing Same as detail, 2.

detailed estimate of construction cost A
forecast of construction cost prepared on the
basis of a detailed analysis of materials and labor
for all items of work, 1 as contrasted with an
estimate based on current area, volume, or simi-
lar unit costs.

detectable warning According to the Ameri-
cans with Disabilities Act, a change in a walking
surface that alerts a disabled person to the possi-
bility of a hazard ahead.

detector See sensor.

detention basin In a storm-sewer system, a
basin for temporarily storing storm water during
periods of peak downpour.

detention door A heavy steel door containing
fixed lights of laminated glass protected by bars
and muntins of tool-resistant steel; used in pris-
ons and mental hospitals.

detention screen A window screen especially
designed for institutions of detention; fabricated
of screen mesh which is woven of large stainless
steel wires; a massive steel frame holds the mesh
under tension.

detention window A metal awning window
esp. designed for institutions of detention. The
sashes (ventilators, 2) are only 6 in. (15 cm) to
8 in. (20 cm) high and pivot on full-width hard-
ened steel rods about 1 in. (2.5 cm) in diameter.

deterioration Of concrete, the same as disinte-
gration.

deterministic design Design which is based
on the mechanical and physical properties of
materials, building elements, and structures
involved.

306

diaconicon

detonating cord A flexible cord having a
high-explosive center core; when detonated, it
then detonates other cap-sensitive explosives
with which it is in contact.

detonator A blasting cap, electric blasting cap,
electric-delay blasting cap, or nonelectric-delay
blasting cap.

detritus Loose material which results from the
disintegration of rock.

detritus tank In sanitary engineering, a set-
tling tank through which sewage is passed for
the removal of the heavier solids.

detrusion See cleavage, 4.

developed area An area of land upon which
improvements have been made.

developed distance The shortest distance
between two points that free air would travel as
measured horizontally, vertically, or diagonally
in a straight line or around corners.

developed length The length of a pipeline
measured along the center line of the pipe and
fittings.

development 1 . A tract of previously undevel-
oped land which is subdivided for housing and
provided with all necessary utilities, such as
roads, water, electricity, sewers, etc. 2. A large-
scale housing project. 3. Any man-made change
to improved or unimproved real estate, including
but not limited to dredging, excavation or
drilling operations, filling, or paving located
within an area of special flood hazard.

development area (Brit. ) An area in which
the government encourages new and esp. diver-
sified industry in order to promote industrial
stability.

development bond stress Same as anchor-
age bond stress.

development length l.The minimum
length of straight reinforcing bar or reinforcing
rod which is required to anchor it in concrete. 2.
The length of embedded reinforcement required
to develop the design strength at a critical
section.

development rights A property owner's enti-
tlement to develop land in accordance with
local land-use regulations.

device In an electric system, a component that
is intended to carry, but not consume, electric
energy, e.g., a switch.

device function numbers Numbers (as-
signed by ANSI/IEEE Standard C37.02) that
provide a convenient way of indicating the func-
tion of various types of electrical devices on
drawings or in written material.

devil float, devil, nail float A wooden hand
float with nails projecting from each corner;
used to roughen the surface of plaster to provide
a key for the next coat.

devil float

deviling Scratching or roughening plaster.

devitrification Crystallization in glass.

dewater To remove water from an excavated
job site, usually by draining or pumping.

dewatering Pumping water from a site to
maintain a dry and stable condition during con-
struction.

dewpoint The temperature at which air
becomes saturated with water vapor and below
which moisture is likely to condense; varies with
the amount of moisture contained in the air.

dextrin, amylin, starch gum A starch-like
compound having strong adhesive properties; an
amorphous, odorless, sweetish-tasting, white,
water-soluble gum; used as a wallpaper adhesive.

DF 1. Abbr. for daylight factor. 2. On drawings,
abbr. for drinking fountain.

DFI Abbr. for "Deep Foundations Institute."

dflct Abbr. for "deflection."

d.f.U. Abbr. for drainage fixture unit.

DHW Abbr. for double-hung window.

DIA On drawings, abbr. for "diameter."

diabase Rock having the same composition as
basalt, but with larger crystals which are just vis-
ible to the unaided eye; also called traprock.

diaconicon 1 . Originally a place where the
deacons kept the vessels used for the church ser-
vice. 2. In Greek churches, a sacristy to the right
of the sanctuary.

307

DIAG

DIAG 1. On drawings, abbr. for diagonal. 2. On
drawings, abbr. for "diagram."

diaglyph l.A relief engraved in reverse; an
intaglio. 2. A sunk relief.

diagonal In a framed structure, an inclined mem-
ber running across a panel, 7, e.g., as in a truss.

diagonal bond A type of raking bond, in thick
masonry walls, consisting of a header course
(usually every sixth course) with its bricks laid at
a diagonal with the exterior and interior faces.

diagonal brace An inclined structural mem-
ber in compression and/or tension; usually
employed to stabilize a frame against horizontal
forces, such as wind.

diagonal braces

diagonal bridging l.See crossbridging. 2.
See bridging. 3. A combination of horizontal

bridging and diagonals in the same plane;
spans between the top flange of one beam (or
joist) and the bottom flange of the adjacent
beam (or joist), in a plane perpendicular to
both.

diagonal buttress One extending at 45° from
the right-angle corner of two walls.

diagonal chimney stacks Several brick
chimney stacks that are square in cross section
and oriented so that diagonals through them
form a straight line; usually corbeled and joined
at their tops.

diagonal chimney stacks

diagonal bridging, 2

diagonal crack An inclined crack, usually at
about 45° to the center line, beginning at the
tension surface of a concrete member.

diagonal grain A defect in lumber, usually the
result of careless sawing, in which the wood
grain is at an angle to the long dimension.

diagonal joining Decorative work formed by
bricks or tiles which are set obliquely and sym-
metrically with respect to a vertical or a horizon-
tal axis.

diagonal pitch In riveted joints having two or
more rows of staggered rivets, the distance from
one rivet in one row to the nearest rivet in the
next row.

diagonal rib A rib crossing a bay or compart-
ment of a vault on a diagonal.

diagonal sheathing A covering of wallboards
nailed to exterior studs or rafters at an angle of
approximately 45 degrees.

308

diamond vault

diagonal sheathing

diagonal slating, drop-point slating A

method of laying shingles or slates so that the
diagonal of each slate runs horizontally.

diagonal tension In reinforced concrete or
prestressed concrete, the principal tensile stress
resulting from the combination of vertical and
horizontal stresses.

diakonikon An apse or recess at the east end
of an early Christian church.

diametral compression test Same as split-
ting tensile test.

diamicton In ancient Roman architecture, a
type of masonry wall construction having a hol-
low cavity filled with broken material of every
description.

diamond-bond pattern Same as diaperwork.

diamond ashlar A rectangular building stone
having a face that is pyramidal rather than flat.

diamond drill In exploratory drilling, a rotary
drill having a coring bit which is studded with
black diamonds.

diamond fret, lozenge fret, lozenge mold-
ing A molding consisting of fillets intersect-
ing so as to form diamonds or rhombuses.

diamond light, diamond pane A small

pane of glass, either diamond-shaped or square-
shaped, and set diagonally in lead cames in a
window sash. Also called diamond glass.

- rOj^-SfK.,

two types of diamond frets

diamond lights

diamond matching, four-piece butt match-
ing A method of cutting and piecing four adja-
cent, square-cut pieces of wood veneer so that a
diamond pattern results at the center.

diamond-mesh lath A common type of
expanded metal lath; used as a base for plaster.

diamond notch Same as V-notch.

diamond pattern On a roof, a pattern of tiles
or shingles whose lower edges are V-shaped.

diamond slate An asbestos cement shingle or
slate, approx. square in shape, with two corners
nipped for use in diagonal slating.

diamond work See diaperwork.

diamond vault A ribless prismatic vault using
thin concrete-slab construction.

309

diaper

diaper An allover pattern with motifs placed in
a repeated design, esp. on a rectangular or diago-
nal grid.

diaperwork, diaper pattern A decorative
masonry pattern formed by brick headers having a
dark glazed finish exposed on one end; often laid in
the flat unbroken surfaces of gable walls in repeated
patterns of diamonds, crisscrossed lines, inverted
V's, or chevrons; also called black diapering.

diaperwork

diaphragm l.A diaphragm plate. 2. A floor
slab, metal wall panel, roof panel, or the like,
having a sufficiently large in-plane shear stiff-
ness and sufficient strength to transmit horizon-
tal forces to resisting systems.

diaphragm action Descriptive of a floor sys-
tem in which all columns that frame into the
floor from above and below are maintained in
the same position relative to each other.

diaphragm plate A relatively thin, usually rect-
angular plate, used to stiffen a metal-framed struc-
ture; provides additional strength and rigidity.

diaphragm pump A pump in which the pis-
ton is replaced by a clamped diaphragm that is
set in vibration by a reciprocating rod, attached
at its center.

diaphragm valve A valve whose action is
controlled by fluid pressure on a diaphragm.

diastyle See intercolumniation.

diathyrum A vestibule in an ancient Grecian
house with the street door at one end and the
door to the courtyard at the other.

diatomite, diatomaceous earth, kieselguhr
A white or light gray, chalky, natural siliceous
material; obtained by mining deposits of fossil
remains of small marine life; used as an extender
in paints, as an aggregate in lightweight concrete,
as a waterproofing material in portland cement, as
a filter for water, and as an abrasive.

diatoni 1 . In ancient Greek and Roman
masonry construction, stones which extend the
full thickness of the wall; same as through
stones. 2. Quoins which project from a wall and
have two dressed faces.

ancient construction with diatoni

diazoma The wide horizontal walkway between
the lower and upper tiers of seats in a Greek
theater.

- rir i n ^

diazoma, D

310

diffusing glass

dichroic reflector lamp An incandescent
lamp (usually a PAR lamp) with a built-in light
filter which colors the light or removes a signifi-
cant part of the infrared power from the light
beam.

dictyotheton A type of masonry used by the
ancient Greeks; composed of square-cut stones,
forming a network or chessboard pattern; similar
to the opus reticulatum of the Romans.

die 1 . The middle portion of a pedestal between
the base (or plinth) and the surbase; also called
a dado. 2. A tool for cutting threads on pipe,
screws, etc.

die, 1

dieback A condition often found in woody
plant material where browning and death of the
plant cells begin from the tip inward and may
continue as far as the woody or perennial part of
the plant.

die»cast Descriptive of a casting produced by
forcing molten metal into a mold.

die cut Said of a member or device that has
been punched from sheet material.

dielectric fitting In a water supply system, a
special type of adapter (such as a union) used to
connect a pipe containing copper with a pipe
containing iron; used between dissimilar metals

NONMETALUC
BUSHING

to prevent galvanic action from causing corro-
sion failure.

die line A longitudinal depression or protrusion
formed on the surface of drawn or extruded
material owing to imperfections on the die
surface.

die- squared timber A timber having a square
cross section, at least 4 in. (10 cm) on a side.

differential leveling The process of establish-
ing the difference in elevation between any two
points by using a level, 1 and a leveling rod.

differential settlement Relative movement
of different parts of a structure caused by uneven
sinking of the structure.

differential subsidence The difference in
subsidence between two points on a structure.

diffuse illumination Lighting arranged so
that an object is illuminated from a very large
number of directions, rather than predomi-
nantly from a single direction.

diffuse light Light which is random in direc-
tion.

diffuse-porous wood A hardwood having
pores of uniform size and distribution through-
out each annual ring.

diffuser l.Any device, object, or surface that
scatters light (or sound) from a source. 2. For air-
conditioning systems, see air diffuser.

diffuse reflection Reflection of light from a
rough surface which scatters it in all directions.

dielectric fitting

diffuse reflection

diffuse sound Sound is said to be perfectly dif-
fuse in a room when the sound waves travel in
all directions with equal probability and the
sound level of the reflected sound is everywhere
equal.

diffusing glass Glass having an irregular sur-
face to diffuse light; may be fabricated in flat
sheets by rolling or pressing, or in hollow shapes
by blowing.

311

diffusing panel

diffusing panel A translucent material, such
as that covering the lamps in a luminaire, used
to distribute light over an extended area and to
conceal the lamps and interior of the luminaire.

diffusing surface A reflecting surface which
scatters incident light or sound in all directions.

diffusion lens A glass lens used to widen the
distribution of light from a source so as to increase
its diffusion.

diffusion streak On a clad sheet, a surface
streak which results from the diffusion of alloy-
ing constituents into the coating from the core
during thermal treatment.

dig-down pit Same as sunken pit.

digestion tank The first tank of a septic tank
system in which organic material is processed.

digger A small excavator.

diglyph A member having two vertical chan-
nels or grooves, without the two lateral half
grooves which characterize the triglyph.

dike, dyke 1. A dry stone wall. 2. A long low
dam. 3. A bank of earth from an excavation. 4.
An earth embankment which acts as a coffer-
dam for keeping water out of an excavation.

dilatancy The expansion of cohesionless soils
when subject to shearing deformation.

diluent A thinner.

diluent air Air which is induced or admitted
into a flue in order to dilute the products of com-
bustion.

DIM. On drawings, abbr. for "dimension."

dimension A geometric element in design, such
as length, angle, or the magnitude of a quantity.

dimensionally stable Said of a building mate-
rial whose dimensions remain relatively constant
with changes in temperature and humidity.

dimensional stability The degree to which a
material maintains its original dimensions when
subjected to changes in temperature and humid-
ity. See equilibrium moisture content.

dimension lumber, dimension stuff Lum-
ber cut to a particular size and stocked for the
building industry; usually 2 to 5 in. (5.1 to 12.7
cm) thick and 5 to 12 in. (12.7 to 30.5 cm)
wide.

dimension ratio The average specified diame-
ter of a pipe divided by the minimum specified
wall thickness.

dimension shingles Shingles which are uni-
form, rather than random, in size.

dimension stock 1. Square-edged lumber usu-
ally of timber size; softwoods are at least 4 by 1 2 in.
(10.2 to 30.5 cm), and hardwoods at least 4 Vz in.
(1 1.5 cm) thick. 2. Timber from which dimension
lumber is cut; maximum waste is left at the mill.

dimension stone Stone that is selected,
trimmed, or cut to desired shapes and/or sizes for
such uses as building stone, markers, paving
blocks, flagging, or curbing.

dimension stone tile A dimension stone that
is less than 3 /t in. (20 mm) thick.

dimension stuff See dimension lumber.

dimension work Masonry constructed with
dimension stone.

diminished arch, skeen arch, skene arch
An arch having less rise or height than a semi-
circle.

diminished bar A glazing bar or muntin
shaped so as to appear thinner in cross section
than it actually is.

diminished column A column having a
greater diameter at its base than at its capital.

diminished stile, diminishing stile, gun-
stock stile A door stile having different
widths above and below the middle rail, as in a
glazed door in which the stile is narrower in the
glazed portion.

diminishing courses On a roof: courses of
tiles that diminish in height in going from the
eaves to the ridge, thereby providing the appear-
ance of greater height.

diminishing piece Same as diminishing pipe.

diminishing pipe, taper pipe A pipe of
diminishing diameter which acts as a reducer.

diminishing rule A template used to establish
the entasis of a column.

diminishing stile See diminished stile.

dimmer A device which varies the light
intensity of a light source without appreciably
affecting the spatial distribution of the light;
usually an electric control device that varies
the current flow and hence the light output of
the lamp.

dimmer room A room in which are located
the dimmers for controlling the lights for an
auditorium or theater.

312

direct cross-connection

DIN Abbr. for "Deutsche Industrie Normal"
(Germany Industry Standard).

dinette A recess off a living room, foyer, or
kitchen that is used for dining purposes.

dinging A single, rough coat of stucco on a
wall; often scored with a tool to form imitation
masonry joints.

dingle An obsolete term for a temporary enclo-
sure constructed at the entrance to a building as
protection against the weather.

dining bay, dining recess Same as dinette.

dining room The principal room used for
meals, in which the family in a private house, or
guests in a hotel, come together at mealtimes.

Diocletian window See Venetian window.

diorama l.A large painting, or a series of
paintings, intended for exhibition to spectators
in a darkened room in a manner to produce by
optical illusions an appearance of reality. 2. A
building in which such paintings are exhibited.

diorite Medium- to coarse-grained rock com-
posed essentially of plagioclase feldspar and
ferromagnesium minerals.

dip Of a trap, 1 the lowest portion of the inside
top surface of the channel through the trap.

dip

dipcoat A paint or plastic coating which is

applied by completely immersing an article in a

tank of the coating; usually applied as a finishing

or waterproof coating.
dip edge An edge on a metal flashing that is

formed to promote the flow of water away from

vertical surfaces.
diplinthius In ancient Roman construction,

masonry which is two bricks thick.
dip solution Any chemical solution used to

produce a specific color or finish on copper or

copper alloys.

dipteral A classical temple having two rows of
free columns, rather than a single row, surround-
ing the cella. Also see peripteral, pseudodipteral.

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dipteral temple, shown in plan

dipylon 1. In ancient Greece, a gate consisting
of two separate gates placed side by side. 2. (cap.)
A gate of this type on the northwestern side of
Athens.

direct-acting thermostat An instrument
which activates a control circuit when a prede-
termined temperature is reached.

direct cold-water supply A series of water
outlets fed directly from a water main.

direct cross-connection l.A continuous
cross-connection or interconnection such that
the flow of water from one system to the other
may occur under the slightest pressure differen-
tial between the two piping systems. 2. Any

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direct cross-connection

313

direct current

connection (such as a shutoff valve) between a
potable water-supply line and a nonpotable
source at which there is the possibility of cont-
aminating the water supply should the valve
(a) leak or (b) be opened when it should be
closed.
direct current In an electric circuit, a current
that flows in one direction only. Also see alter-
nating current.

direct cylinder The tank of a direct-fired
water heater.

direct dumping The discharging of concrete
directly into place from a crane bucket or mixer.

direct expense All items of expense directly
incurred by or attributable to a specific project,
assignment, or task.

direct-fired air heater An air heater in which
all the heat of combustion is discharged into the
airstream; used in factories, warehouses, etc., to
raise the temperature of air, which is brought in
from the outside, to room temperature.

direct-fired water heater A water heater in
which the source of heat (gas, oil, or electricity)
is located at the water tank — in contrast to an
indirect water heater.

direct glare Glare resulting from high bright-
ness or insufficiently shielded light sources in the
field of view or from reflecting areas of high
brightness.

direct glazing Glazing that is set into a struc-
ture instead of into a frame mounted within a
structural opening.

direct glue down See glue down.

direct heating Warming of a space by means of
exposed heated surfaces (e.g., from a stove, fire,
radiators, or pipes); both radiant heating and
convection heating take place.

direct hot-water system A system in which
water is heated in a central boiler and then dis-
tributed throughout a building; see the illustra-
tion under hot-water heating system.

direct- indirect lighting Lighting in which
the luminaires are in the general diffuse category
but emit little or no light at angles near a hori-
zontal plane drawn through them.

directional lighting Lighting, predominantly
from a preferred direction, which provides illu-
mination on the work plane or on an object.

direct leveling The determination of differ-
ences of elevation by a continuous series of short
horizontal lines; the vertical distances from these
lines to adjacent ground marks are determined by
direct observations on graduated rods with a lev-
eling instrument equipped with a spirit level.

direct lighting Lighting in which luminaires
distribute 90% to 100% of the emitted light in
the direction of the surface to be illuminated,
usually in a downward direction.

direct luminaire A luminaire which emits
90% to 100% of its total output below a hori-
zontal plane through it.

direct nailing Same as face nailing.

direct-plunger elevator A hydraulic elevator

which has a piston (plunger) directly attached to
the elevator car frame.

Directoire style A transitional classicist style
preceding the Empire style, named after the
Directoire rule in France (1795-1799).

directory board An information board with
changeable letters or symbols.

direct personnel expense Salaries and wages
of principals and employees engaged on a proj-
ect, assignment, or task, including mandatory
and customary benefits.

direct return system A piping arrangement
for a heating system (or air-conditioning or
refrigeration system) in which the heating (or
cooling) fluid, after it has passed through each
heat exchanger, is returned to the boiler (or
evaporator) by the shortest direct path.

direct selection The selection of a contractor
by the owner, based on the owner's evaluation of
the contractor's availability, competence, and
reputation, as well as his or her fee.

direct solar water-heating system A solar
water-heating system in which water passes
directly from the potable water supply, through
the collectors and storage, to the hot-water
supply.

direct sound The sound which travels directly
from the source to the point of observation — no
reflection of sound is involved.

direct sound level The sound level of the
direct sound in a room.

direct stress Stress without bending or shear;
only compressive or tensile stress.

314

discontinuous impost

direct system A heating, air-conditioning,
or refrigeration system in which heat is
exchanged directly with a surrounding mate-
rial or space.

direct water heater Same as direct-fired
water heater.

dirt-and-stick chimney, dirt chimney

Same as clay-and-sticks chimney.
dirt-depreciation factor See luminaire dirt-
depreciation factor.

dirt resistance The ability of a paint coating
(or the like) to resist soiling by foreign material
deposited on, or embedded in, the dried coat-
ing.

disability According to the Americans with
Disabilities Act, a legally specified incapacity or
disqualification.

disability glare Glare that reduces visual per-
formance and visibility and often is accompa-
nied by discomfort.

disappearing stair, folding stair, loft ladder

A swinging stair, usually a folding ladder, which
enables passage to an attic space or loft. The
stair is fixed to a trapdoor which, when closed,
hides the stair from viewers below.

discharge coefficient See coefficient of dis-
charge.

discharge head The energy per unit weight of
fluid on the discharge side of a pump.

discharge lamp Any lamp that produces light
by means of phosphors as a result of an electrical
discharge through one or more gases or vapors
within the lamp's envelope (e.g., see fluorescent
lamp).

discharge opening The opening at the base
of a refuse chute through which the refuse
drops into a refuse container or refuse com-
pactor.

discharge pipe Any pipe that conveys the dis-
charge from plumbing fixtures, appliances, or
the like.

discharge valve A valve which regulates or
closes off the flow of a fluid.

discharging arch, relieving arch, safety
arch An arch, usually segmental and often a
blind arch, built above the lintel of a door or
window to discharge the weight of the wall
above the lintel to each side.

discharging arch

discoloration Any change in color from the
original color or from the desired color.

discomfort glare A low-level glare that causes
discomfort and annoyance, but does not neces-
sarily impair vision or visual performance.

disconnecting means A device (usually a
circuit breaker, a fused switch, or a fused circuit-
breaker-assembly) that disconnects the conduc-
tors of an electric circuit from the source of
supply.

disconnecting trap Same as interceptor.

discontinuous construction Construction in
which there is no solid connection between the
rooms of a building and the building structure;
or between one section of a building and another;
esp. used to prevent the transmission of noise
along a solid path.

discontinuous easement An easement requir-
ing for its exercise an action by one party, as a
right-of-way.

discontinuous impost A shafted impost,

where the arch moldings are different from the
moldings of the pier from which the arch springs.

discontinuous impost

315

disc tumbler lock

disc tumbler lock Same as cylindrical lock.

dished hole A hole whose upper edge has been
enlarged.

dishing The grading of the surface of the ground
or pavement, usually to promote drainage.

disintegration Of concrete or the like, the
deterioration into small fragments or particles.

disk Sander A sanding machine or a power
sander which has a circular abrasive (usually
sandpaper) disk which rotates; used for smooth-
ing or polishing surfaces.

dispersant An admixture which is capable of
maintaining finely ground materials in suspen-
sion; used as a slurry thinner or grinding aid.

dispersing agent An addition or admixture
capable of increasing the fluidity of pastes, mor-
tars, or concrete.

dispersion 1. Any gas, liquid, or solid contain-
ing finely dispersed particles in suspension. 2. A
paint containing finely dispersed particles of pig-
ment or latex.

displacement pile A solid pile or hollow pile
whose lower end is closed so that in being driven,
the pile displaces an equivalent soil volume
(either by compaction or soil displacement).

displuviatum An atrium, the roof of which was
sloped outward from the compluvium instead of
toward it.

disposal field Same as absorption field.

disposal unit See waste-disposal unit.

dissolved solids See solutes.

distance block A wood block which separates
two components from each other at a fixed
distance.

distance piece Same as setting piece.

distance separation For fire-protection require-
ments, the separation between an exterior wall of a
building and an interior property line, or the center
line of an adjacent street, or the exterior wall of
another building; all measured at right angles to
the exterior wall.

distegia Same as episkenion.

distemper A paint containing earth pigments,
calcium carbonate, tinting colors, glue size, or
casein, mixed with water; tempera.

distemper brush A wide flat paintbrush with
long bristles; used in applying distempers, such
as calcimine.

distillation A water purification process in
which water is converted to a vapor by boiling it,
and then reconverted to purified water by cool-
ing the vapor.

Volatile Oas Vsnt

Waler Supply In

Healing Elemenl
the process of distillation

distributed load A load which acts evenly
over a structural member or over a surface that
supports the load.

distribution The movement of freshly mixed
concrete toward the point of placement, either
by motorized tools or by hand.

distribution-bar reinforcement, distribu-
tion steel In a reinforced concrete slab, small-
diameter steel reinforcing bars, usually at right
angles to the main reinforcement; intended to
spread a concentrated load on the slab and to
prevent cracking.

distribution board Same as distribution switch-
board.

distribution box 1 . In sanitary engineering, a
box in which the flow of effluent from a septic

distribution box

316

dividers

tank is distributed equally into the drain tile lines
that lead to the absorption field. 2. A junction
box.

distribution center A point in an electrical
system in a building where secondary voltage
(usually a low voltage) is distributed to different
circuits within the building. Generally includes
automatic overload protective devices that pro-
vide protection for the electric system in the
event that the system is called upon to exceed its
safe operating capacity; in that case, the system
shuts down automatically.

distribution cutout In a primary circuit, an
electrical cutout, 3 which disconnects the cir-
cuit as a means of overcurrent protection.

distribution line In sanitary engineering, a
line of distribution tile.

distribution panel Same as panelboard.

distribution reinforcement See distribution-
bar reinforcement.

distribution steel See distribution-bar rein-
forcement.

distribution switchboard An electric switch-
board used to distribute power within a building;
enclosed in a metal box which includes circuit
breakers, fuses, and switches.

distribution tile In a sewage-disposal system,
clay or concrete tile pipe, laid with open joints,
which carries effluent from a distribution box.

distribution transformer A transformer that
reduces the primary voltage to a secondary
(lower) voltage for distribution within a build-
ing.

district surveyor A British term for building
inspector.

distyle Having two columns in front; used in
describing a classical building.

distyle, temple shown in plan

distyle in antis Having two columns in front

between antae.
ditcher, ditching machine See trencher.

ditching machine

ditriglyph An interval between two columns
such as to admit two triglyphs in the entablature
instead of one, as usual.

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ditriglyph

DIV On drawings, abbr. for division.

divan 1 . In Muslim countries, a council room or
hall for a court of justice. 2. A smoking room.

diversion valve Same as diverter.

diversity The nonsimultaneous occurrence of
maximum demands on any given part of a
system.

diversity factor 1. In an electric wiring system,
the ratio of the sum of the individual maximum
demands of the various subsystems to the maxi-
mum demand of the whole system. 2. In a gas pip-
ing system, the ratio of the maximum probable
demand to the maximum possible demand.

diverter A valve (sometimes motorized) at a
junction of a pipe tee; used to change the flow
from one branch to another.

divided door Same as Dutch door.

divided light Glass in a window or glazed door
that is divided into smaller panes by secondary
framing members; see muntin.

divided tenon Same as double tenons, 1.

dividers A pair of compasses having both legs ter-
minating in points; used for measuring, transfer-
ring, or comparing distances between two points
when a precise measurement is required; also used

317

divider strip

to scribe an arc, radius, or circle, and to compare or
transfer measurements directly from a rule.

divider strip A strip of metal embedded in
terrazzo; used to serve as a control joint or as a
decoration.

division One of the sixteen basic organizational
subdivisions used in the AIA uniform system for
construction specifications, data filing, and cost
accounting. See illustration for contract docu-
ments.

division bar See muntin.

division wall See fire wall, 1.

diwan Same as divan, 1.

dkg Abbr. for "decking."

DL l.On drawings, abbr. for dead load. 2. On
drawings, abbr. for deadlight.

D-line crack See D-crack.

DN On drawings, abbr. for "down."

DO. On drawings, abbr. for "ditto."

doat See dote.

dobying Same as mud-capping.

dock 1 . A platform, usually the height of the
floor or truck vans, which facilitates loading and
unloading; a loading dock. 2. Short for scene
dock.

dock bumper A resilient bumper attached to a
loading dock, 1 to absorb truck impacts against it.

docked gable Same as jerkinhead roof.

document deposit See deposit for bidding
documents.

dodecastyle Having twelve columns in the
front row; said of buildings of classical type.

DOE Abbr. for the US Department of the Envi-
ronment.

dog Same as dog iron.

dog anchor See dog iron.

dog bars Vertical rails in the lower portion of a
gate.

dog-ear 1. An external corner made by folding
a sheet of material without cutting it. 2. The
corner of a sheet of material which is folded
over. 3. Same as crossette. 4. The projections at
the corners of a door or window casing.

dog-eared fold Same as dog-ear.

dogging device A mechanism which fastens
the crossbar of a panic exit device in the fully
depressed position.

dog iron, dog anchor A short bar of iron
with its ends bent at right angles and pointed so
as to hold together the two pieces into which
they are driven.

dog iron

dogleg Said of a facility having one or more
right-angled bends, as in a dogleg stair.

dogleg brick A special brick not having a rect-
angular shape; instead, the edge along the nar-
rowest side is not a straight line but forms an
obtuse angle. These bricks are especially used
where the face of a wall forms an obtuse angle;
this avoids the use of cut bricks and a mortar
joint where the face of the wall changes direc-
tion; an angle brick.

dogleg chisel Same as corner chisel.

dog-leg pile A pile which has been bent or
curved in driving.

dogleg stair, doglegged stair A half-turn
stair which has no wellhole between successive
flights; the rail and balusters of the upper and
under flights fall in the same vertical plane.

dogleg stair

dog nail 1. A large nail having a head that pro-
jects considerably on one side. 2. A wrought nail
used for fastening door hinges.

318

domestic hot-water heater

dog-run cabin Same as dogtrot cabin.

dog's ear, dog ear Same as crossette.

dog shore A horizontal shore that is framed
between vertical surfaces (without braces) such
as between two buildings.

dog's tooth Same as dogtooth.

dog's-tooth course Same as dog-tooth course.

dog-tooth frieze A horizontal course of bricks,
laid diagonally on edge in a masonry structure,
which provides a decorative band in the form of
a frieze.

dogtooth, tooth ornament 1. An ornament
in medieval architecture and derivatives, of
more or less elaborate motif, usually pyramidal
with notched sides, the diagonal portions usually
resembling petals or leaves which radiate from
the raised point. 2. A brick laid with its corners
projecting from the wall face.

dogtooth, 1

dog-tooth course A horizontal band of bricks,
or course, that is laid diagonally on edge; each
brick is set so that one corner projects from the
face of the wall, often at an angle of 45 degrees;
also called a dog's-tooth course.

dog-tooth course on a brick chimney

dogtrot A breezeway.

dogtrot cabin A dwelling, often of log con-
struction, consisting of two single-room cabins

separated from each other by a covered open-air
passageway (dogtrot); a common wood-shingled
pitched roof typically covers both cabins, and
each cabin has its own entrance and a chimney
at its gable end. The dogtrot or breezeway not
only serves to link the cabins, but also provides
an outdoor sitting area. Also called a double-pen
cabin.

dogtrot plan See possum-trot plan.

dollop A gob of bonding material, such as
cement, applied in a specific area.

dolly l.A block of hardwood placed on the
upper end of a pile; acts as an extension piece
and as a cushion during pile driving. 2. A tool
for holding the head of a rivet and absorbing
the impact while the other head is being driven.
3. A low cart or truck used for transporting
heavy or bulky equipment.

Dolly Varden siding Beveled wood siding
which is rabbeted along the bottom edge.

dolmen, table stone A prehistoric tomb of
standing stones, usually capped with a large hor-
izontal slab.

dolomite l.A mineral form of calcium-
magnesium carbonate; a constituent of some
building limestones. 2. Limestone consisting
principally of the mineral dolomite; dolostone.

dolomitic lime A trade term and misnomer for
high-magnesium lime; the product does not con-
tain dolomite.

dolomitic limestone Limestone that contains
more than 10% but less than 80% of the mineral
dolomite.

dolostone See dolomite, 2.

dome l.A curved roof structure spanning an
area; often spherical in shape. 2. A square pre-
fabricated pan form; used in two-way joist
(waffle) concrete floor construction. 3. A vault
substantially hemispherical in shape, but some-
times slightly pointed or bulbous; a ceiling
of similar form. Also see geodesic dome and
saucer dome.

dome light A skylight having the shape of a
shallow dome; often fabricated of glass or plastic;
may be set into a roof to provide supplementary
daylighting below it.

domestic hot-water heater Packaged equip-
ment which heats water for domestic purposes.

319

Domestic Revival style

Domestic Revival style A style of architec-
ture in England in the 19th century loosely
patterned after elements of the Queen Anne
style, Domestic Revival, and aspects of the Pic-
turesque Movement as well as the Arts and
Crafts Movement; often characterized by timber-
framed houses, ornate bargeboards, brickwork in
diaper patterns, tall decorative chimney stacks,
and leaded windows; a forerunner of the shingle
style, in which tiles were used rather than wood
shingles. Also called Old English style.

domestic sewage See sanitary sewage.

domical Pertaining to, resembling, or charac-
terized by a dome, as a domical church.

domical vault See coved vault.

dominant estate Where a restriction on use of
one piece of real property is imposed in order to
confer a benefit upon the owner of another, the
former is called the servient estate and the latter
the dominant estate. For example, if ownership
of one field confers upon its owner the easement
or right to walk across the field of a neighbor in
order to reach the highway, the field whose
owner has that right is the dominant estate and
that which may be crossed is the servient estate.

donjon Same as keep.

dook Same as furring strip.

door l.An entrance way. 2. A barrier (usually
solid) which swings, slides, tilts, or folds to close
an opening in a wall or cabinet or the like. For
additional definitions and illustrations of spe-
cific types, see automatic door, balanced door,
battened door, blank door, blind door, board-
and-battened door, car door, casement door, cel-
lar door, Christian door, class-A door, class-B
door, class-C door, class-D door, class-E door,
crapaudine door, cross-and-bible door, divided
door, double-acting door, double door, double-
margin door, Dutch door, dwarf door, Egyptian
door, elevator car door, false door, fire door, flap
door, flush door, folding door, framed door,
French door, half door, Holy door, jib door, land-
ing door, ledged-and-braced door, ledged door,
overhung door, Palladian door, paneled door,
pocket door, revolving door, roll-up door, sash
door, scuttle door, sham door, single-acting door,
sliding door, storm door, swinging door, trap-
door, unframed door, vertical plank door,
weather door, wicket, witch door, z-braced bat-
tened door, zambullo door.

r- — r Y—f

LOCK RAIL

il V.

BOTTOM HAIL

door nomenclature

door band Same as door bar.

door bar A heavy bar across a door to prevent it
from being opened, such as a plank dropped
between metal holders on each side of the door-
frame.

door bevel The bevel which is provided on the
stile edge (lock edge) of a door so that the door
may swing free of the doorframe; usually about
3° toward the doorstop, 1.

door bolt A manually operated sliding rod or
bar attached to a door for locking it; a spring is
not part of the locking mechanism.

door bolt

320

doorframe

doorbrand 1. A bar used to fasten a door. 2. A

strap hinge which holds in place the planks of a

door.
door buck A wood or metal subframe, set in a

wall, to which the finished frame is attached;

also called a rough buck or sub-buck.
door bumper See doorstop, 2.
doorcap The wall area or decorative element

directly above a doorway, often ornamented.
door casing, doorcase The finished frame

surrounding a door; the visible frame.

aoor casing

door catch See catch.

door check Same as door closer, 1.

doorcheek A doorjamb.

door class See class-A door, class-B door, etc.

door clearance l.The clearance between the
bottom of a door and the finished floor. 2. Same
as frame clearance. 3. The clearance between
the meeting edges of a pair of doors.

door closer 1. A device combining a spring for
closing and a compression chamber into which
liquid or air escapes slowly, thus providing a

means of controlling the speed of the closing
action; also called a door check. 2. In elevators,
a device or assembly of devices which closes an
opened car or hoistway door by the use of gravity
or springs.

door closer bracket A device which permits
a door closer, 1 to be installed on the doorframe,
rather than directly on the door.

door contact, door switch An electric con-
tacting device for opening and closing a circuit,
which is attached to a doorframe and operated
by opening or closing the door.

doorframe An assembly built into a wall con-
sisting of two upright members (jambs) and a
head (lintel) over the doorway; encloses the
doorway and provides support on which to hang
the door.

HEADER

door closer, 1

CORNER
REINFORCEMENT

STEEL STUO
ANCHOR (CLIP)

WOOD STUD

ANCHOR (CLIP)

MASONRY
ANCHOR (CLIP)

BASE ANCHOR
(CLIP)

321

doorframe anchor

doorframe anchor An adjustable device,
fabricated of metal, used to attach a doorframe
to the surrounding structure; also see jamb
anchor.

door furniture (Brit.) Any functional or dec-
orative fitting for a door, excluding the lock and
hinges. Same as door hardware.

door grille A grille in a prepared door opening
which allows air to pass through but restricts
vision and acts as a partial barrier.

door guide In a sliding door, a channel, 1 that
keeps the door plumb while it moves.

door hand See hand.

door head 1. The uppermost member of a
doorframe. 2. A horizontal projection above a
door.

doorhood A projecting covering over an exter-
nal door to provide shelter from rain or snow.

door head, England (15th cent.)

DOOR
HEAD

JAMB

door head, doorjamb

door holder A device that holds a door open at
selected positions.

doorhood

door jack A frame for holding a wood door
in place while it is off its hinges and being
planed.

doorjamb, doorcheek, doorpost The ver-
tical member on each side of a door.

door knob The knob or handle that releases
the latch on a door, permitting it to be
opened.

door knocker A hinged knob, bar, or ring of
metal, attached to the outside of an exterior
door, to enable a person to announce his
presence.

doorknocker, England (15 th cent.)

door landing A level floor surface immediately

adjacent to a threshold of a doorway.
door latch See latch.

322

door tree

door leaf 1. A separately movable division of a
folding or sliding door. 2. One of a pair of doors.

door light The glass area in a door.

door lining The finish of wood, metal, marble,
etc., which surrounds the top and sides of a door-
way.

door lock A device that prevents a door from
being opened except with a key; for example, see
box locks or case locks; also see lock.

door louver In a door, an opening with a series
of slats, blades, or piercings which permit the
passage of air.

door mullion The center vertical member of a
double-door opening, set between two single
active leaves; usually forms the strike side of
each leaf; may be removable. Also see mullion.

doornail l.A large-headed nail against which
the knocker strikes. 2. A large-headed nail used
to decorate or strengthen a door.

door opening, opening size The size of the
doorframe opening measured from jamb to jamb
and from floor line or threshold to head of frame;
usually equal to the actual door size plus clear-
ances.

door operator On elevators, a device or
assembly of devices which opens and closes a car
door and/or hoistway door by power other than
by hand, gravity, springs, or the movement of
the car.

door pivot See pivot, 2.

doorplate A plate on the exterior side of a door
which gives the name of the occupant, apart-
ment number, or the like.

door pocket The boxing or chamber in a wall

which receives a sliding door when it is in the
open position.

doorpost 1 . See doorjamb. 2 . A heavy post that
frames one side of a doorway; in the past, doors
were sometimes hinged directly to such a post
instead of to a doorframe.

door rail A horizontal cross member which
forms part of the framework of a door; connects
the hinge stile to the lock stile, both at the top
and bottom of the door and at intermediate
locations; may be exposed, as in paneled doors,
or concealed, as in flush doors.

door roller A hardware accessory, consisting of
wheels on a track, which supports a sliding door.

door saddle Same as threshold, 1.

door schedule A tabulation, usually on a blue-
print or in specifications, which lists all doors
required on a job, indicating sizes, types, loca-
tions, and special requirements.

door screen A wire screen panel fixed in a
door to exclude insects but permit the passage of
air; may be removable to permit replacement by
a glazed panel in cold weather.

door set An assembly of manufactured compo-
nents of which a door is comprised, e.g., the
door, door frame, door lining, etc.

doorsill The horizontal board or metal plate on
the floor directly beneath a door; covers the
joint where two types of floor materials meet;
also called a saddle.

doorstead A doorway, including all compo-
nents of the door and doorframe.

doorstep A step at a door; often one of several
at the exterior of an outer door.

door stile A vertical structural member of the
door itself; this is in contrast to a vertical
structural member of the doorframe, which is
called a jamb. The inner stile (i.e., the stile
nearest the axis about which the door swings)
is called the hinge stile; the outer stile is called
the lock stile.

doorstone The stepstone at the threshold of a
door.

doorstop 1. A strip against which a door shuts
in its frame. 2. A device placed on a wall behind
a door, or mounted on the floor, to prevent
opening the door too wide; also called a door
bumper.

door strip A strip attached to the bottom edge
of a door to cover the gap between the bottom
edge and the doorsill.

door surround A decorative element or struc-
ture around a doorway; for example, see Gibbs
surround.

door sweep See sweep strip.

door swing See hand.

door switch See door contact.

door threshold Same as threshold, 1.

door track A metal track or rail on which a
sliding door moves.

door transom A transom, 2.

door tree The jamb or sidepiece of a door.

323

door trim

door trim The casing or moldings used around a
doorframe to conceal the crack or joint between
the frame and wall or for decorative effects.

door unit l.A door and frame assembly. 2. As
specified in building codes: the clear opening of
each door in a required fire exit.

doorway An opening in a wall, with a door,
which provides a passageway into a room or
building.

door window A French door.

dope 1 . A material added to a building material
such as mortar or plaster to retard or accelerate
the set. 2. A material added to a batch of paint
to adjust it to specifications. 3. A solution of cel-
lulose nitrate applied to a porous fabric as a pro-
tective coating. 4. A compound used in making
a pipe joint, as a lubricant and to ensure a
leakproof joint.

Doric capital The topmost member of a col-
umn or pilaster of the Doric order.

Doric cyma A cyma recta.

Doric order In Classical architecture and
derivatives, the column and entablature devel-

oped by the Dorian Greeks. Characterized by
sturdy proportions, a simple capital, a frieze
usually having regularly spaced triglyphs and
metopes, and mutules in the cornice; plainer
than the Corinthian order or the Ionic order
(although the Tuscan order later introduced by
the Romans was even plainer). The Roman
Doric column has a base but is usually not
fluted (see illustration of base, which follows);
in contrast, the Greek Doric column is usually
fluted but has no base. Compare with Tuscan
order.
dormant, dormant tree In a timber-framed
house, a large horizontal beam that supports
beams of a lesser size.

dormant window Same as dormer.

dormer, dormer window A structure project-
ing above a sloping roof, usually housing a vertical
window. It is not part of the roof structure but is
framed separately, and often provides daylight and
ventilation for a room located in a garret or loft
space. For definitions and illustrations of specific
types, see arched dormer, deck dormer, eyebrow
dormer, flat-head dormer, gable dormer, hipped
dormer, inset dormer, mission dormer, oval
dormer, Palladian dormer, pedimented dormer,
pitched-roof dormer, pointed dormer, polygonal
dormer, recessed dormer, ridge dormer, round
dormer, segmental dormer, shed dormer, through-
the-cornice dormer, triangular dormer, wall
dormer, watershed dormer.

dormer cheek The vertical side of a dormer.

dormer window, dormer A vertical window
which projects from a sloping roof, placed in a
small gable.

dormer window

Doric order: a, Greek; b. Roman

dormitory A place, building, or room to sleep in.
dormitory suburb See satellite community.
dorsal Same as canopy.

324

double corner block

dorsel 1. A canopy. 2. Same as reredos.

dorter, dortour A dormitory, esp. in a
monastery.

dosing tank In sanitary engineering, a collec-
tion tank for sewage which is subsequently dis-
charged for further processing.

dossal Same as reredos.

dossel 1. Same as reredos. 2. A hanging of silk,
satin, damask, or cloth of gold at the back of an
altar of a church and sometimes also on the sides
of the chancel.

dosseret A member or supplementary capital
resting on the top of the capital of a column; see
impost block; also called a double capital.

dot A small spot of plaster placed on a plastering
surface, or a temporary nail; to assist the plas-
terer in leveling a wall and in obtaining proper
plaster thickness.

dote, doat, doze A form of decay in which
wood becomes soft and weak and has a dull life-
less appearance.

doty Said of timber which has decayed.
double-acting butt Same as double-acting

hinge.
double-acting door A door that swings in

both directions; see swinging door.
double-acting frame A doorframe which

does not contain doorstops, thereby permitting

installation of a double-acting door.
double-acting hinge A hinge which permits

motion in either of two directions; used on

swinging doors.
double-acting pump A reciprocal pump in

which the reciprocating motion of a piston does

work in both directions.
double angle Two L-shaped metal structural

members which are fastened together, back to

back.

double architrave An architrave, 1 having
two decorative bands around an opening (such
as a door or window in a wall of a building); usu-
ally the bands are in different planes, separated
by an ornamental molding.

double ax An ax having a two-edged blade.

double back See double up.

double bead Two beads, side by side; there is
no other surface or molding between them.

double-bellied Descriptive of a baluster whose
profile is the same at both its upper and lower
ends.

double-bellied baluster A baluster whose
upper half has the same profile as the lower half.

double-bend fitting In plumbing, an S-
shaped pipe fitting.

double-beveled edge The edge of a door
(along the lock stile) which is beveled from the
center of the edge toward each door face.

double-break switch In electric wiring, a
switch which opens a conductor at two points.

double bridging Bridging which is placed
between adjacent joists at positions which
divide the joists into three lengths.

double capital Same as dosseret.

double-center theodolite Same as repeating
theodolite.

double chimney l.A pair of exterior chim-
neys, of approximately the same size, one on each
side of a gable end of a house. 2. The chimneys
for two fireplaces that open back to back, serving
two different rooms; commonly has two flues.

double church A church constructed in two
stories, affording two places of worship, one
above the other; a large hole in the floor of the
upper church enables the two congregations to
hear the same service.

double-cleat ladder Similar to a single-cleat
ladder, but wider, with an additional center rail
which allows for two-way traffic of workmen
ascending and descending.

double cloister An ambulatory that is divided
in two by a series of columns or piers.

double-cone molding A molding enriched
with carved cones joined base to base and apex
to apex.

double corner block, pier block, pilaster
block A concrete masonry unit having solid
rectangular end faces as well as solid rectangular
side faces.

double corner block

325

double course

double course, doubling course A double
layer of shingles or the like, one over the other,
providing a minimum coverage of two thicknesses.

BUILDING PAPER

^SHEATHING
double course

double-crib barn See crib bam.
double cross-vault See cross vault.

double-cut file A file having two sets of cutting
ridges, each set crossing the other; the ridges are
diagonal with respect to the center line of the file.

double-cut saw A saw whose teeth have been
cut so that the blade cuts on both the pull and
the push strokes.

double decker A two-story house that pro-
vides living quarters for two families; it has one
apartment on each floor and a separate entrance
for each family.

double-decker barn A barn having three
levels (including a loft) that is built into a hill-
side having a steep slope.

double-decker porch See two-tiered porch.

double dome A pair of domes, one set within
the other, both of which have the same center of
curvature.

double door Two single doors (leaves) hung in
the same doorframe.

double-door bolt Same as cremone bolt.

double-dovetail key, hammerhead key A
key made of hardwood which is used to join two
timbers; has a dovetail on each end which is
driven into a corresponding recess in each timber.

double eaves course Same as double course.

double egress frame A doorframe which is
prepared to receive two single-acting doors
swinging in opposite directions, both doors
being of the same hand.

double door with fanlight above

double-ended substation A electric sub-
station consisting of two switchboards in one
common assembly, separated physically and
electrically by a "tie circuit breaker."

double ender A medieval church having an
apse at both the east end and the west end.

double-end-trimmed Descriptive of lumber
which is sawn reasonably square on both ends.

double-entry stair Same as double stair.

double-extra-strong pipe A standard des-
ignation for steel pipe in which the thickness
of the pipe wall has been increased beyond
that of standard-weight pipe to provide double
strength.

double-faced 1. Descriptive of any joinery, as
a molding, which is formed of two parts having
faces in different planes. 2. Any material which
is finished on both sides.

double-faced hammer A hammer with a
striking face at each end of the head.

double-faced ware, porcelain enamel ware

Ware that has a finish coat on both surfaces.

double feathering The subdivision of large
cusps into smaller ones.

double Flemish bond A brickwork pattern
showing a Flemish bond on both faces of a wall.

double floor, double-joisted floor, framed
floor A floor in which the binding joists sup-
port the common joists above and the ceiling
below.

326

double lean-to roof

double format pavior A brick or tile made
esp. for paving and having double the bed face,
or double the longer face perpendicular to the
bed face.

double-framed floor A double floor in which
the binding joists are framed by girders.

double-framed roof A roof in which longitu-
dinal members (such as a ridge beam and purlins)
are used.

double framing Using twice the usual number
of framing members to provide additional
strength.

double-fronted lot A lot bounded by a street
on the front and back.

double-gable roof An M-roof.

double glazing Two panes of glass, usually
parallel, with an air space between; used to pro-
vide increased thermal and/or sound insula-
tion.

double glue-down See glue down.

doublehanded saw A saw operated by two
men, one at each end.

double-headed nail, scaffold nail, form
nail A nail having two heads, one above the
other; the upper head is driven with a hammer,
and it is used to withdraw the nail; the lower
head bears on the surface into which the nail is
driven; used on temporary structures such as
scaffolds, form work, etc.

""ilium J|~~]

double-headed nail

double header A header joist made of two
pieces of lumber, fixed together by bolts or nails,
to provide greater strength than a single piece.

JOIST HANGER

double header

double-hipped roof A hipped roof having a
double slope; also see bonnet roof.

double house l.A pair of semi-detached
houses having a plan that is symmetric on both
sides of the common wall; each of the two units
has its own entry. 2. See Cape Cod house. 3. See
Charleston house.

double-hung window, double-hung sash
■window A window having two vertically
sliding sashes, each closing a different part of the
window; the weight of each sash is counterbal-
anced for ease of opening and closing.

MUNTIN

UPPER
STILE

LOWER

STILE

TOP RAIL

HORIZONTAL BAR
Jl I

N UPPER MEETING RAIL

yd!

BOTTOM RAIL

double-hung window: terminology

double-intersection truss A truss, each panel

of which has two intersecting diagonals.
double jack rafter A short rafter that joins a

hip to a valley.
double-joisted floor See double floor.
double junction A fitting for a water pipe or

a drainage pipe which has a branch on each

side.
double lancet window A window having a

mullion which is so shaped as to form two lancets.
double lath Wood lath, twice the normal

thickness.
double lean-to roof A V-shaped roof formed

by two lean-to roofs meeting at their low edge

with a gutter at their intersection.

327

double-lock seam

double-lock seam A type of seam between
the edges of adjacent metal sheets; formed by
making a double fold, then dressing down to
form a seam.

double-lock seam

double-lock welt Same as double-lock seam.

double L stair A platform stair with two inter-
mediate landings, one near the top and one near
the bottom, with a 90° change of direction at
each landing.

double-margin door A door having the
appearance of a double door.

double measure In joinery, work which has
molding on both sides.

double meeting rail A horizontal fixed meet-
ing rail where two adjacent pivoted sashes (ven-
tilators, 2) meet.

double meeting stile The vertical equivalent
of a double meeting rail.

double-molded Said of doors that are molded
on both sides of the framing.

double monastery A monastery and a nun-
nery adjacent to each other, sharing the same
church and under the rule of the same superior.

double offset In plumbing, two changes of
direction which are in succession in a continu-
ous pipe.

double partition A partition built with sepa-
rated framing members for each face so as to
form a cavity space in the center for purposes of
sound insulation or to conceal sliding doors.

double-pen cabin A log cabin having two
adjacent rooms under a common roof; usually has
a chimney at each end of the cabin; often a porch
across the full width of the cabin. Also see center-
hall cabin, dogtrot cabin, saddlebag cabin.

double piled Said of a house that has two par-
allel rows of rooms which are separated by a cor-
ridor

double-pile house A house that is two rooms
deep. Also see pile, 2 and single-pile house.

double-pitched Having a pitch in two direc-
tions, as a gambrel roof.

double-pitched roof A roof having two flat
slopes on each side of a central ridge; for exam-
ple, see gambrel roof.

double-pitched skylight A skylight which
has two slopes and straddles the ridge of a roof.

double-pole scaffold A scaffold supported
from the base by a double row of uprights, inde-
pendent of support from the walls and con-
structed of uprights, ledgers, horizontal platform
bearers, and diagonal bracing.

double-pole switch In electric wiring, a
switch which has two blades (and associated
contacts) for opening or closing both sides of a
circuit simultaneously.

double porch A two-tiered porch in which
the porches on the first and second stories
appear to be virtually identical in design.

double pour In built-up roofing, two separate
applications of a top coating of bitumen and sur-
facing; esp. used on level roofs designed to hold
water.

double-quirked bead See quirk bead, 2.

double-rabbeted frame A doorframe having
recesses along both sides so that a door can be
hung on either side of the frame.

double raised panel See raised panel.

double-rebated frame Same as double-
rabbeted frame.

double return stair, side flights A stair hav-
ing one flight from the main floor to an interme-
diate landing and two side flights from that
landing to the floor above.

double return stair

double Roman tile A Roman tile having an
additional roll up the center of the tile that
matches (and is parallel to) the roll at its edges.

double roof A timber framing system in which
the common rafters rest on purlins which pro-
vide intermediate support.

328

double vault

double-run stairs Two separate flights that
start and finish at the same levels, and cross each
other about the center point of each stair.

double- saddle notch At a corner of a log
cabin, one of a pair of rounded notches cut on
opposite sides of a horizontal log near one end; it
forms a joint at the corner with a round
unnotched log set at a right angle between such
a pair of notched logs. Sometimes simply called
a saddle notch; also see notch.

double shear The shear to which a member is
subject when the shearing stress is along two sec-
tion planes.

double-shell tile Ceramic tile with double
faces separated by short webs.

double- shouldered chimney Same as
stepped-back chimney.

double sliding door A pair of sliding doors
which can pass each other, each in its own track.

double skirting A baseboard that is much
higher than usual.

double square See adjustable square.

double stair An open stair having a pair of
staircases leading down from a landing; usually
designed to be impressive; compare with double-
return stair.

double step A double notch cut into a tie beam
which supports a rafter in a timber framing system.

double- strength glass Sheet glass having a
thickness of between 0.118 in. (3.00 mm) and
0.113 in. (3.38 mm).

double- suction pump A pump having a spi-
ral-shaped casing in which the water enters the
impeller from both sides of the impeller so that
hydraulic unbalance is practically eliminated.

double-sunk Recessed or lowered in two steps,
as when a panel is sunk below the surface of a
larger panel.

double surface treatment Two successive
treatments applied to a surface, such as asphaltic
material followed by a mineral aggregate.

double-swing door Same as double-acting door.

double- swing frame A doorframe which is
prepared to receive a pair of single-acting doors,
both of which swing in the same direction.

double T-beam A precast concrete member
composed of two beams with a common slab
across the top.

double tenons l.Two tenons, side by side, at
one end of a member; also called a divided
tenon. 2. Two tenons, one at each end of a mem-
ber, which are coaxial.

double tenons, 1: a,b

double-throw bolt A door bolt that can be
projected beyond its first position, into a second
(or fully extended) position to provide addi-
tional security.

double-throw switch In electric wiring, a
switch which can charge the circuit connections
by moving the switch blade from one of two sets
of contact clips into the other.

double-tiered porch Same as two-tiered porch.

double-tier partition A partition which
extends two stories in height.

double up, double back A method of apply-
ing plaster; first the plaster base coat is applied;
then this is covered with plaster from the same
mix before the base coat has set. A form of two-
coat work.

double vault A vault, usually domical, consist-
ing of an inner shell separated from a higher
outer shell.

double vault

329

double wall

double wall A masonry wall composed of two
walls with a space between them; the space may
be filled with a material such as fiberglass to pro-
vide additional thermal insulation and sound
insulation.

double-wall cofferdam A cofferdam formed
by a double wall of sheeting (such as interlock-
ing steel sections) and backfilled with soil or
crushed stone.

double waste and vent Same as dual vent.

double-welded joint In arc welding and in
gas welding, any joint welded on both sides.

double welt Same as double-lock seam.

double 'window l.Two windows, one outside
the other, as a storm window, used to provide
improved thermal and noise insulation. 2. A
window which is double glazed, with an air space
between. 3. Two windows, side by side, which
form a single architectural unit.

double 'wrench A wrench having a set of jaws
at each end.

double-wythe wall See double wall.

doubling course See double course.

doubling piece 1. A cant strip. 2. A tilting fil-
let. 3. See arris fillet.

doubly prestressed concrete Concrete which
is prestressed in two directions that are mutually
perpendicular.

doubly reinforced concrete Concrete hav-
ing both compression reinforcement and ten-
sion reinforcement.

doucine A cyma molding.

doughnut See concrete collar.

Douglas fir, Oregon pine, red fir, yellow
fir A strong, medium-density, medium- to
coarse-textured softwood; widely used for ply-
wood and as lumber and timber in construction
work.

dovecote A structure that houses doves or
pigeons; often square, hexagonal, octagonal, or
round in plan and one-and-a-half or two stories
high; typically topped with a finial; once popular
because the birds provided a tasty source of fresh
meat. The interior is honeycombed with niches
in which the birds may rest. Also called a pigeon
house or pigeonnier.

dovetail 1 . A splayed tenon, shaped like a
dove's tail, broader at its end than at its base.

■Mm

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dovecote

dovetail, 1

dovetail, 2

2. A joint formed by such a tenon which is fit-
ted into the recess of a corresponding mortise.

330

dowel plate

dovetail anchor slot A slot which is nailed to
a concrete form (the open end is against the
wood); the ends of the slot are temporarily
closed with a piece of wood or cellular foam.
After the concrete is poured and the forms
removed, the slot is used for anchoring masonry
to the concrete.

dovetail baluster A baluster having a dovetail
base for attachment to the stair tread.

dovetail brick A brick which has one end
formed like a wedge; the other end has a recess
to receive the wedge-like end of another brick.

dovetail cramp A dovetail-shaped cramp for
lifting masonry.

dovetail cutter A rotary cutting tool, used to
shape dovetails.

dovetail feather joint A double-dovetail key.

dovetail half-lap joint, dovetail halved
joint, dovetail halving joint A joint
formed by two members of equal thickness in
which a dovetail, 1 at the end of one member is
fitted into a corresponding mortise in the sec-
ond member; half the thickness of each is
removed.

dovetail half-lap joint

dovetail hinge Same as butterfly hinge.

dovetail joint Same as dovetail, 2.

dovetail lath, dovetail sheeting A type of

metal lath, now called rib lath,
dovetail margin Any band or strip which is

dovetailed.
dovetail miter Same as secret dovetail.
dovetail molding, triangular fret molding

A molding decorated with fretwork in the form

of dovetails.
dovetail notch At a corner of a log house, a

notch in the shape of a dovetail at the end of a

rectangular exterior timber; forms a strong,

interlocking rigid joint when mated with an

appropriately notched hewn timber at right

angles to it. Compare with half-dovetail notch.
dovetail plane A plane used for cutting

tongues and grooves for dovetail joints.
dovetail saw A small tenon saw having a very

thin blade and fine teeth.

pxzdD

etail .'

dovetail sheeting See dovetail lath.

dowel A cylindrical wood or metal rod; used to
secure two pieces of wood, stone, concrete, etc.,
by inserting it in a hole through the two mem-
bers.

dowel-bar reinforcement Short reinforcing
bars of steel which extend approximately equally
into two abutting pieces of concrete, to increase
the strength of the joint.

dowel bit, spoon bit A boring tool, the barrel
of which is a half cylinder terminating in a
conoidal cutting edge or radial point; used with
a brace.

dowel joint Any carpentry joint making use of
dowels.

dowel joint

dowel lubricant A lubricant applied to steel
reinforcing bars in expansion joints to reduce
bond with the concrete, so as to promote unre-
strained longitudinal movement.

dowel pin 1. A dowel. 2. A metal pin having
a sharpened or deformed end used to fasten
mortise-and-tenon joints.

dowel plate A hardened steel plate containing
holes of various diameters; used to cut dowels by

331

dowel screw

driving pegs through the holes to remove excess
wood.

dowel screw A dowel having threads on both
ends.

downbrace A timber member between a cor-
ner post and a doorsill.

downcomer l.A downspout. 2. Any pipe in
which the flow is substantially vertical.

down conductor The vertical portion of an
electric conductor used in a lightning protection
system to provide a lightning current path from
the air terminals to ground.

downdraft, Brit, downdraught l.A down-
ward current of air in a chimney or flue, often
carrying smoke with it. 2. A downward current
of air resulting from the passage of air across a
window surface, which cools it and increases its
density so that it moves downward.

down-feed system l.A piping arrangement
for a heating (or air-conditioning or refrigera-
tion) system, in which the heating (or cooling)
fluid is circulated through supply mains that are
above the levels of the heating (or cooling)
units they serve. 2. A water distribution system
in which the water distribution main is located
at the top of the pressure zone; the distribution-
main supplies the risers that distributes water
downward to the lowest point of the zone.

down lead Same as down conductor.

downlight A small direct luminaire (recessed,
surface-mounted, or suspended) whose light is
directed vertically downward.

METAL
HOUSING

LAMP

CEILING

downlight

downpipe See downspout.

downpipe shoe The fitting at the base of a
downspout that changes the direction of the
flow of water, discharging it horizontally, clear of
the wall.

downspout, conductor, downcomer,
downpipe, leader, rain leader, rainwater
pipe A vertical pipe, often of sheet metal,

downspout

used to conduct water from a roof drain or gutter
to the ground or cistern.

downstage The front part of a stage, nearest
the audience.

downstairs The lower floor or floors of a
dwelling.

downzoning The change in the zoning classi-
fication of a property from a zoning classification
of higher use to one that is lower; for example,
from commercial use to residential use.

DOZ On drawings, abbr. for "dozen."

doze See dote.

dozer Same as bulldozer.

dozer shovel A bulldozer having a front-
mounted bucket used for digging, loading, or
pushing.

dozy See doty.

DP On drawings, abbr. for dew point.

dpc Abbr. for dampproof course.

d.p.c. brick A brick having an average water
absorption not greater than 4-5% by weight.

dpm Abbr. for "dampproof membrane."

DR 1. On drawings, abbr. for drain. 2. Abbr. for
dressing room. 3. Abbr. for dining room.

draft, Brit, draught l.A current of air or
gases, as an air current which flows through a
flue, chimney, or heater; or a localized air cur-
rent which results in more heat being withdrawn
from a person's skin than is normally dissipated.
2. A narrow, dressed border around the face of a
stone, usually about the width of a chisel edge;
also called a drafted margin or margin draft.

draft bead, deep bead, sill bead, ventilat-
ing bead, window bead A small fillet or
strip which is fixed to the sill of a double-hung

332

Dragon style

window; permits ventilation at the meeting rail

while avoiding a draft at the sill; also called a

draft stop.
draft chisel Same as drafting chisel.
draft curtain See curtain board.
drafted margin See draft. 2.
drafted masonry Masonry having a draft, 2

around the face of the stone.
draft fillet In glazing where putty is not used, a

fillet on which the glass rests.

draft hood 1 . A device fitted into or on top of
a flue to prevent downdrafts. 2. An open enclo-
sure over a gas-fired furnace. Serves to create a
stack effect which more readily mixes the
exhaust gases with air and directs the mixture to
the chimney; prevents back drafts from getting
into the furnace.

drafting chisel A chisel esp. used for cutting a
border or line at the edge of a stone.

drafting machine A device, used in drafting,
that provides the combined functions of a T-
square, scale, triangle, and protractor; it is
attached to a drawing board or drawing table.

drafting machine

drafting pen A pen especially designed for use
in mechanical drawing. See drawing pen.

drafting pen

draft regulator A device that maintains a
desired draft in a gas appliance by automatically
reducing the draft to the selected value.

draft stop A building material installed to pre-
vent the movement of air, smoke, gases, and
flame to other areas of the building through a
large concealed passage, such as a suspended
ceiling.

drag l.A piece of sheet steel with a toothed
edge along the long dimension; used to level and
scratch plaster to produce a key for the next
coat; a comb. 2. A tool consisting of a steel plate
having a finely serrated edge; used to dress stone
by dragging it back and forth across the surface.

dragged Said of an exposed surface over which
a drag or comb has been pulled or worked to
produce a textured surface.

dragging beam Same as dragon beam.
dragging piece Same as dragon beam.

dragline A bucket attachment for a crane; used
for removing earth by pulling the bucket toward
the crane.

dragline

dragon beam, dragon piece A short, hori-
zontal piece of timber which bisects the angle
formed by the wall plate at the corner of a wood-
frame building; one end serves to receive and
support the foot of a hip rafter; the other end is
supported by a dragon tie.

dragon's blood A naturally occurring deep red
resin; used as a tinting material, principally in
varnishes.

dragon piece See dragon beam.

dragon post A post at the corner of a house
that has a jetty at the front as well as a jetty on a
side of the house.

Dragon style A mode of architecture, popular
in 19th-century Scandinavia, that exhibited
seagoing motifs, such as dragon figureheads;
based on traditional log construction and said to
be reflective of pride in the Viking Age.

333

dragon summer

dragon summer A dragon beam of unusually
large size.

dragon tie An angle brace which supports one
end of a dragon beam.

drag shovel Same as backhoe.

drag strut A structural member used to transfer
a lateral load across a building to some part of
the vertical structural system.

drain 1. Any pipe in a building-drainage system
which carries waste water or water-borne waste.
2. Any pipe or channel for carrying waste water
or storm water.

drainage 1. A drainage system, either artificial
or natural. 2. The water that is drained off. 3.
The removal, by natural or artificial means, of
surface water or groundwater.

drainage area An area having a drainage
channel beneath the surface.

drainage basin The area within which all sur-
face water flows toward the lowest point of its
elevation.

drainage channel A channel for conveying
storm-water runoff; usually lined with concrete,
grass, riprap, or the like, to reduce erosion of the
channel.

drainage classification A system of drainage
classification devised by the Soil Conservation
Service of the US Department of Agriculture.
The most porous soil in this classification sys-
tem is said to be excessively drained, in which
water is removed from the soil very rapidly. In
contrast, is the least porous soil, classified as
very poorly drained, in which water is removed
from the soil so slowly that the water table
remains at or near the surface most of the time.

drainage envelope The materials which com-
pletely surround a pipe, providing support and/or
protection.

drainage fill 1. Lightweight concrete which is
placed on roofs or floors to promote drainage.
2. A base course of granular material placed
between a sub-grade and floor slab to retard the
capillary rise of moisture.

drainage fitting, Durham fitting A cast-
iron, threaded fitting, used on drainage pipes;
has a shoulder such as to present a smooth, con-
tinuous interior surface.

drainage fixture unit Same as fixture unit.

POCKET

drainage fitting

drainage hole An opening in a construction
which permits unwanted water to drain away,
e.g., from behind a retaining wall.

drainage piping All or any part of the drain-
pipe of a plumbing system.

drainage system The piping network within a
structure which conveys sewage, rainwater, or
other wastes from their point of origin to a point
of disposal, such as a public sewer or a private
treatment facility.

drainage tile Same as drain tile.

drainboard, Brit, draining board A work
surface, adjacent to a sink, having a built-in
pitch so that it drains into the sink.

drain cock A small cock or faucet, at the low-
est point in a tank, for draining off the liquid.

drain field Same as absorption field.

drainpipe 1. Any pipe that serves as a drain. 2.
Same as downspout.

drain spout Same as downspout.

drain test A water test or an air test of a
drainage or vent system for leakage.

drain tile A hollow tile, usually laid end to end
as piping (with open joints) in soil in order to
drain water-saturated soil, or used to permit fluid
in the hollow-tile pipe to disperse into the
ground (as in an absorption field).

drain trap Same as trap, 1.

draped tenon Same as deflected tenon.

drapery panel 1. See linenfold. 2. One unit of
drapery.

drapery track Same as curtain track.

draught Same as draft.

draught excluder A British term for door strip.

draught stop Same as fire stop.

draw bar A bar that can be slid through a
socket attached to the face of a door into

334

dredge

another socket attached to the door jamb, thus
securing the door in a closed position.

drawbolt Same as barrel bolt.

drawbore A hole in the tenon of a mortise-
and-tenon joint which is not in line with the
holes of the mortise; when a pin is driven
through, the joint becomes tighter.

drawbridge At the entrance of fortifications, a
bridge over the moat or ditch, hinged and pro-
vided with a raising and lowering mechanism so
as to hinder or permit passage.

drawbridge

draw cock See pet cock.

draw curtain A theater curtain that moves
horizontally, usually divided in the middle so that
each half can be pulled to one side of the stage.

drawdown The distance by which the ground-
water level is lowered as a result of pumping.

drawer dovetail See lapped dovetail.

drawer kicker A wood piece which prevents a
drawer from tilting downward when it is pulled
out.

drawer roller A device used to ease the sliding
of a drawer open or shut, usually by means of a
metal or fiber wheel rotating on a metal frame.

drawer runner, drawer slip In drawer fram-
ing, one of a pair of strips on which the drawer
slides.

drawer slide A mechanism employing guides
and rollers that support a drawer and permit its
easy operation.

drawer stop A block which stops the inward
movement of a drawer when it has reached its
proper position.

drawing room A formal reception room, usu-
ally in a prominent location of a large home,
mansion, or manor house.

drawings The portion of the contract docu-
ments showing in graphic or pictorial form the
design, location, and dimensions of the elements
of a project; usually include plans, elevations,
details, and schedules, as well as graphical and
pictorial portions of the contract documents.

draw-in box Same as pull box.

draw-in system In electric wiring, a system
using conductors installed in conduits, ducts, race-
ways, and boxes, thereby permitting removal and
replacement of any conductor without disturbing
any part of the building structure or finish.

draw-off tap See bibcock.

drawknife, drawshave A woodworking tool
consisting of a blade with a handle at each end;
the tool is drawn over the surface toward the user.

drawknife

drawn finish A smooth, bright finish on metal

tubing, wire, rod, bar, and strip; obtained by
drawing the metal through a die.

drawn glass, flat-drawn glass, flat-drawn
sheet glass Sheet glass fabricated by the con-
tinuous drawing of the molten glass from a fur-
nace; has fire-finished surfaces, not perfectly flat
and parallel, resulting in some distortion.

drawn product A product formed by pulling
material through one or more dies.

drawn 'wire Wire brought to final dimensions
by being drawn through one or more dies.

drawshave A drawknife.

dredge 1 . A floating excavator for removing
earth or rock from under water. Usually

335

drencher system

accomplished by clamshell, power shovel, or
cutterhead combined with a suction line. 2. To
remove soil from an area under water.

drencher system A fire-protection sprinkler
system which provides a water spray to protect
the exterior of a building against fire; see deluge
sprinkler system.

dress circle In an opera house, theater, or the
like, a tier of seats above the main seating area —
usually the first or lowest.

dressed Descriptive of brick, lumber, or stone
which has been prepared, shaped, or finished by
cutting, planing, rubbing, or sanding one or
more of its faces.

dressed all around Said of a timber that has
been planed smooth on all four sides.

dressed and matched boards, D and M
boards, dressed and matched lumber,
planed matchboards, tongue-and-groove
boards Boards or lumber that has been planed
smooth; cut so that a tongue along one edge fits
into a groove cut along the edge of the adjacent
piece.

dressed and matched boards

dressed dimension See dressed size.
dressed lumber, dressed stuff, surfaced

lumber Lumber having one or more of its

faces planed smooth.
dressed size The dimensions of a timber after

sawing and planing; usually about % in. (0.95

cm) in thickness or Vi in. (1.27 cm) in width less

than the nominal size.
dressed stone Stone that has been worked to

desired shape; the faces to be exposed are

smooth; usually ready for installation.
dressed stuff See dressed lumber,
dressed timber See dressed lumber.

dresser A plumber's tool used to flatten sheet
lead and straighten lead pipe.

dresser coupling A clamp-style coupling for

unthreaded pipe.

dresser joint A type of Normandy joint.

dressing, dressings 1. Projecting ornamental
moldings and carved decorations of all kinds. 2.
Masonry or molding of better quality than the
facing brick; used around openings or at corners
of buildings; often made of gauged brick. 3.
Smoothing a stone surface. 4. Bossing.

dressing compound, bonding compound

A hot- or cold-applied bituminous liquid used to
coat exposed surfaces of roofing felt.
dressing room A room used for changing cos-
tumes and applying makeup in a theater, opera
house, and the like.

dress plate Same as cover plate.

DRG On drawings, abbr. for "drawing."

drier 1. An additive which is mixed with paints
and varnishes to speed their drying by absorbing
oxygen from the air. 2. See soluble drier. 3. A
device containing a desiccant, placed in a refrig-
erant circuit; used to collect and hold within the
desiccant all water in the system in excess of the
amount which can be tolerated in the circulat-
ing refrigerant.

drier scum See scum.

drier 'white Superficial discoloration of clay-
ware during drying; usually caused by adherence
of soluble salts to the surface of the ware.

drift l.The lateral deflection of a building, due
to wind or other loads. 2. In a water spray
device, the entrained unevaporated water car-
ried from the device by air movement through it.
3. See driftpin, 2. 4. A deposit of loose materials
such as gravel, rock fragments, clay and other
soils which have been driven together by water,
wind, or ice.

driftbolt 1 . A short rod or square bar driven
into holes bored in timber, for attaching adja-
cent sticks to each other or to piles; varies from
1 to 2 ft (0.3 to 0.6 m) in length; often provided
with a head or with a sharpened end; also called
a drift, or driftpin. 2. A steel bolt used to drive
out other bolts.

drifter A type of pneumatic, percussive rock
drill.

336

drip edge

drift index 1 . The ratio of the lateral deflection
of a building to its height. 2. The ratio of the lat-
eral deflection of a story of a building to the
height per story.

drift limitation See drift index.

driftpin 1 . A square or round metal rod with
no threads, driven into an undersized, pre-
bored hole as a substitute for a bolt, screw, or
other fastener. 2. A short, tapered rod for
enlarging rivet holes or bringing them into
line; also called a drift. 3. A driftbolt. 4. A
tapered round rod used to align holes in two or
more pieces of metal.

driftpin

drift plug l.A hardwood cylindrical plug
which is driven through a soft-metal pipe to
straighten it. 2. A conical plug driven into one
end of a soft-metal pipe to produce a flare.

drift punch A punch with long taper and blunt
end for aligning holes.

drift punch

drill 1 . A hand- or motor-driven rotary tool used
with a bit for boring holes in a material. 2. A
hand-held tool used to bore a hole in a material
by striking one end with a series of blows. 3. A
machine for boring holes in the ground or in
rock, e.g., in obtaining rock-core samples.

drill bit Same as bit, 1.

drilled-in caisson A composite foundation
column; consists of a heavy wall pipe which is
concrete-filled; the upper end is locked into the
structure, and the lower end is secured in a
socket in rock.

drilled pier, drilled pile A concrete pier or
pile that is cast in place in a hole that has been
bored in soil or rock.

drilled pile Same as augered pile.

drill press A drilling machine mounted in a
stand; a handle is used to lower the drill (which
rotates about a vertical axis) into the work.

drinking fountain A fixture consisting of a
shallow basin, together with a water jet,

designed to provide potable water for human
consumption.

drinking-water cooler A factory-made assem-
bly containing a small refrigeration system and
having the primary functions of cooling potable
water and dispensing such water.

drip, headmold, hoodmold, label, throat-
ing, weather molding l.The outermost
projecting molding around the top of a door
or window, to discharge rainwater. 2. A throat,
2. 3. A pipe, or a steam trap and a pipe con-
sidered as a unit, which conducts condensa-
tion from the steam side of a piping system to
the water or return side of the system. 4. A
container that is typically installed at a low
point in a gas piping system to collect conden-
sate (i.e., liquids that may form within the gas
system).

CONDENSATE

CLEAN-OUT

CON D EH SATE
DRIP

drip, 4

drip bar Same as water bar.

drip cap A horizontal molding, fixed to a door
or window frame to divert the water from the
top rail, causing it to drip beyond the outside of
the frame.

drip cap

drip channel A throat, 2.

drip course Same as dripstone course.

drip edge A strip which extends beyond other
parts of a roof and which directs rainwater off
the roof.

337

drip line

drip line An imaginary line described on the
ground by the outer branch tips of a plant.

drip mold, drip molding Same as drip, 1.

drippage 1 . An accumulation of liquid by drip-
ping. 2. A dripping of water from the gutters or
eaves of a house.

dripping eaves Sloping eaves which project
beyond a wall and are not provided with a gutter
so that water on the roof falls directly to the
ground.

drip sink, lead safe A shallow sink set near
floor level to receive the drip from a faucet or
the like.

dripstone A drip cap made of stone.

dripstone

dripstone course A continuous horizontal

drip molding on a masonry wall.
driptight Said of an enclosure constructed so

that drops of liquid striking the enclosure

(from a specified range of angles) cannot enter

it.
drive band In pile driving, a steel band which

encircles the head of a timber pile to prevent it

from splitting when being driven.

drive cap A steel attachment placed over the
top end of a pile to prevent damage while it is
driven in the ground.

drive nail See drivescrew.

drive band

drive-in A retail business, bank, or motion-
picture theater, designed to permit its patrons
to receive services while they remain in their
automobiles.

driven pile Any pile, such as a precast pile,
which is driven into position at its final position
at the site.

driven 'well A well constructed by driving a
pipe into the ground; usually fitted with a well
point and screen.

drivepipe A pipe, one end of which is sharp-
ened for driving it into the ground; used to
obtain a sample in situ, to reach water, etc.

drive point Same as well point.

drivescrew, screw nail A type of metal fas-
tener; a helically threaded nail, driven with a
hammer; has a higher withdrawal resistance
than a nail with a plain shank; some types may
be removed with a screwdriver.

drive shoe A reinforcement placed at the bot-
tom of a pile to prevent damage to the pile dur-
ing driving.

driveway A private way or road, which is pri-
marily for use by automobiles.

driving band See drive band.

driving machine The power unit which
applies the necessary energy to raise and lower
an elevator or dumbwaiter car or to drive an
escalator, moving walk, or the like.

driving resistance The number of blows of a
pile-driving hammer which are required to
advance the point of a pile a specified distance
into the subsoil.

drn Abbr. for drain or drainage.

dromos The long, deep entrance passageway to
an ancient Egyptian tomb or a Mycenaean bee-
hive tomb.

338

droplight

droop The deviation from a preset value of a
controlled liquid level, temperature, variable
pressure, or differential pressure (at minimum
controllable flow) when the flow through a reg-
ulator is gradually increased from its minimum
controllable flow to its rated capacity.

drop 1. Any one of the guttae under the mutules
or triglyphs of a Doric entablature. 2. In a cabinet
lock, the vertical dimension from the finished
edge of the lock to the center of the cylinder or
tube. 3. In air conditioning, the vertical distance
that a horizontally projected airstream falls from
its original elevation when leaving an outlet,
measured at the end of the throw. 4. Same as
drop curtain. 5. Same as drop panel. 6. Of a stair,
a fitting used to close the bottom end of a tubular
newel. 7. Same as pendant, 2; also see corner
drop. 8. Same as turned drop.

drop apron A strip of metal which is fixed verti-
cally downward at eaves and gutters of a flexible-
metal roof; acts as a drip.

drop arch A pointed arch which is struck from
two centers that are nearer together than the
width of the arch, so that the radii are less than
the span; a depressed arch.

drop black See animal black.

drop bottom-seal See automatic door bottom.

drop box An electric outlet box hung from
above, as in a theater stagehouse where it is fed
by a cable from the overhead gridiron.

drop ceiling See dropped ceiling.

drop chute A device used to confine or to
direct the flow of a falling stream of concrete;
may be articulated or may be fabricated of heavy
rubberized canvas.

drop cloth A large sheet of cloth, paper, or
plastic which is spread over a floor, furniture,
etc., as a protection against paint drippings and
splatter.

drop cord An electric-light cord suspended
and energized from a ceiling outlet.

drop curtain On the theater stage, any curtain
that moves up and down, rather than from side
to side.

drop elbow A pipe elbow, 1 having lugs on the
sides for attaching it to a support.

drop ell Same as drop elbow.

drop escutcheon An escutcheon having a
pivoted plate which covers a keyhole.

drop hammer A heavy weight for driving a
pile into the ground; dropped by gravity along a
set of guide rails onto the head of the pile.

drop handle A door handle that hangs verti-
cally when not in use; often fabricated of brass or
wrought iron.

drop handle

drop-head window A double-hung window

whose lower sash can drop through the window
sill into a pocket below the sill.

drop-in beam A simple beam, usually supported
by cantilever arms, with joints so placed that it
can be installed by lowering it into position.

drop key plate A key plate having a cover
which swings over the key hole to protect it.

droplight l.An electric lamp suspended from
the ceiling on a flexible cord. 2. An electric
lamp, sometimes protected by a wire guard, etc.,
on the end of a flexible cord; used as a portable
work light.

339

drop molding

drop molding A panel molding recessed below
the surface of the surrounding styles and rails.

drop ornament A tear-shaped pendant, or a
representation thereof.

drop-out ceiling A suspended ceiling sys-
tem having listed translucent or opaque, heat-
sensitive panels; when subject to heat, these
panels drop from the suspension system, thereby
exposing the sprinkler system installed above it.

drop panel On the lower side of a flat concrete
slab, the thickened portion which surrounds a
column, column capital, or bracket.

drop panel form A concrete form which is so
erected as to provide the necessary support,
shape, and finish for a drop panel.

dropped ceiling, drop ceiling l.A sus-
pended ceiling. 2. See soffit.

dropped escutcheon Same as key drop.

dropped girder A girder which is dropped
below the floor joists and supports them.

dropped girder

dropped girt, dropped girth A girt which is

dropped below the floor joists and supports them.

dropped roof The roof of an addition to a house,
usually a flat surface of single pitch with its upper
edge somewhat below the eaves of the house.

drop-point slating See diagonal slating.

drop ring A ring which is used as a handle to
operate a lock or latch; the ring remains in a
dropped position when not in use, but it may be
raised and pivoted about the spindle to operate
the lock.

drop siding, novelty siding, rustic siding

An exterior wall cladding of wooden boards (or
strips of other material such as aluminum or
vinyl), which are tongued and grooved or rab-
beted and overlapped so that the lower edge of
each board interlocks with a groove in the board
immediately below it.

drop siding

drop spreader In landscape architecture, a

spreader, 1 for metering and distributing grass

seed and/or fertilizer over a given area.
drop tee A pipe tee having lugs in the sides by

which it can be attached to a support.
drop tracery Tracery hanging from the soffit of

an arch.
drop vent In plumbing, a special individual

vent which connects to a drain or vent pipe at a

point below the fixture served.
drop 'window A vertically sliding window in

which the sash can descend into an opening

below the sill so that the entire window is open

for ventilation.
drop 'wire The electric conductor extending

from an outdoor pole to a building.
drove A mason's chisel having a blade from 2 to

4 in. (5 to 10 cm) broad; a boaster.
drove chisel Same as boaster.
drove work Stone which has been dressed

with a drove; same as boasted work.
drum 1 . One of the cylinders of stone which

form a column. 2. A round or polygonal wall

below a dome, often pierced with windows. 3.

The bell of Composite or Corinthian capitals.
drum hoist Same as hoist, 2.
drum paneling A form of door construction in

which the panels are flush on both sides and

covered with cloth or leather.

340

drying

drum, 1

drum tower A round tower whose diameter is
greater than its height.

drum trap In plumbing, a cylindrical trap, with
its axis in a vertical direction, having a cover
plate which may be unscrewed for access; com-
monly used on the drainpipe from a bathtub or
under a bathroom floor.

drum trap

drunken saw, wobble saw A circular saw

having a blade which is set so that it does not
rotate in one plane; used to cut a groove or kerf.

druxy A piece of wood that has lost its strength
and become brittle.

drwl Abbr. for dry wall.

dry area A covered area, below grade, be-tween
a basement wall and a retaining wall beyond it;
its function is to keep the basement wall dry.

dry-batch weight The weight of the materi-
als, excluding water, used to make a batch of
concrete.

dry-bond adhesive See contact adhesive.

dry-bulb temperature The air temperature
indicated by a dry-bulb thermometer after cor-
rection for the effects of radiation.

dry-bulb thermometer 1. An ordinary ther-
mometer. 2. The one of two thermometers in a
psychrometer which has an unmoistened bulb.

dry-butt joint A joint in stone masonry that is
laid without mortar.

dry chemical extinguishing system A fire
extinguishing system which is used to distribute
an approved fire-extinguishing chemical by
means of a gas under pressure. Fixed piping and
nozzles aid in ensuring proper distribution of the
chemical.

dry concrete Concrete having a low propor-
tion of water so that the plastic mixture is rela-
tively stiff; suitable for use in dry locations; esp.
advantageous where large masses are poured and
compacted and on sloping surfaces.

dry construction The use of dry materials
such as gypsum board, plywood, or wallboard in
construction, without the application of plaster
or mortar.

dry course The first ply of built-up roofing laid
directly over insulation or on a structural deck
without the application of bitumen.

dry-dash finish The finish produced on an
exterior stucco wall by throwing small pebbles
on the stucco when it is partially dry.

dry density The density of soil, or the like,
after it has been heated at a temperature of
22 1°F (105 °C) to a dry condition.

dryer See drier.

dry film thickness The thickness of a dried
coating of paint.

dry filter A filter for cleaning air which removes
dirt by straining or filtering the air through vari-
ous types of screens, fiberglass, or the like.

dry gas Gas having a moisture and hydrocarbon
dew point below any normal temperature to
which the gas piping will be exposed.

dry glazing 1. Any method of securing glass in
a frame by use of a dry, preformed resilient gas-
ket, without the use of a glazing compound. 2.
Patent glazing.

dry hide The hiding power of a coating of paint
after it has completely dried.

dry hydrate A finely ground hydrated lime,
made from calcium or from dolomitic limestone.

drying The physical change of a liquid paint or
varnish film which results in a hard surface, as a
result of the loss of solvent, or a chemical reac-
tion, or a combination of both. Also see air dry-
ing, forced drying.

341

drying agent

drying agent See soluble drier.

drying creep Creep that results from drying.

drying inhibitor A substance added to paints
and varnishes to prevent too rapid drying or skin
drying; used to promote a high gloss and to avoid
a wrinkled film.

drying oil, paint oil A vegetable oil which
oxidizes easily on exposure to air and forms a
hard, dry film; esp. useful in paints.

drying shrinkage The contraction of plaster,
cement paste, mortar, or concrete caused by loss
of moisture.

dry joint A joint without mortar.

dry kiln An oven for drying and seasoning cut
lumber.

dry laid Said of masonry that has been laid
without the use of mortar.

dry lining 1. The surfacing a wall with gypsum
lath, without the application of wet plaster. 2.
(Brit.) Same as Dry Wall.

dry masonry Masonry laid without mortar.

dry mix A mixture of mortar or of concrete
which contains little water in relation to its
other components.

dry mixing Blending of solid materials for mor-
tar or concrete prior to adding the mixing water.

dry-mix shotcrete Shotcrete which is con-
veyed pneumatically; most of the mixing water
is added at the nozzle.

dry moat Around a medieval fortification, a
deep, broad trench not filled with water.

dry mortar A mortar whose constituents are so
proportioned that it is markedly stiffer than
usual, yet with sufficient water for hydration.

dryout A condition in gypsum plaster caused by
water evaporating out of the plaster before it sets.
Such plaster is soft, powdery, and usually light in
color.

dry»pack To ram forcibly a slightly moist port-
land cement-aggregate mixture into a confined
area, as into the space between the top of con-
crete pier underpinning and the bottom of the
building being underpinned. Here the dry-pack
serves as a low-shrinkage filler material that trans-
mits the load of the building to the underpinning.

dry-packed concrete A concrete mixture
sufficiently dry to be consolidated only by heavy
ramming.

dry partition A partition erected and finished
without the application of wet plaster.

dry-pipe sprinkler system l.A complete
fire-protection sprinkler system with sprinkler
heads in which there is no water unless the sys-
tem is actuated (either automatically or manu-
ally) in case of fire; esp. used in areas subject to
freezing temperatures, or to avoid the hazards of
leaking or bursting pipes. 2. A fire sprinkler sys-
tem containing a network of pipes filled with air
or nitrogen under pressure and equipped with an
automatic sprinklers; when the sprinklers open,
the air or nitrogen is released, thereby opening a
valve (called a "dry-pipe valve") which permits
water to enter the pipes and to flow out the
opened sprinklers.

dry-pipe valve The control valve for a dry-
pipe sprinkler system which activates the sys-
tem; must be in a location where it is protected
against mechanical injury and freezing.

dry-powder fire extinguisher One that dis-
charges a fine, dry powder (usually sodium bicar-
bonate, potassium bicarbonate, or ammonium
phosphate) by the pressure of a gas stored in the
same container as the powder; generally suitable
for class-B and class-C fires.

dry press A mechanical press for forming brick,
cast stone, or other ceramic articles from slightly
moistened granular mixtures; pressure is applied
to both top and bottom of the die box.

dry-press brick Brick formed in molds under
high pressures from relatively dry clay (5 to 7%
moisture content).

dry-process enameling A porcelain enamel-
ing process in which the metal article is heated
to a temperature above the maturing tempera-
ture of the coating; then the coating materials
are applied to the hot metal, in the form of a dry
powder, and fired.

dry return In a steam heating system, a return
pipe which carries both water of condensation
and air.

dry riser inlet Same as fire department con-
nection.

dry riser system Same as dry standpipe sys-
tem.

dry rising main British term for dry standpipe.

dry-rodded volume The volume which an
aggregate occupies when compacted dry under

342

D.S.

the standardized conditions used in measuring
unit weight of aggregate.

dry-rodded weight The weight per unit vol-
ume of an aggregate when compacted dry under
standardized conditions.

dry rodding In measuring the weight per unit
volume of coarse aggregates, the process of com-
pacting dry material in a calibrated container by
rodding under standardized conditions.

dry rot The decay of seasoned wood caused by
fungi of a type capable of carrying water into the
wood they infest.

dry rubble construction Masonry of rubble
which is laid without mortar.

dry saturated steam, dry steam Steam
containing no water in suspension.

dry shake See monolithic surface treatment.

dry sheet A nonbituminous felt or a light roof-
ing paper applied between the roof-deck and the
roofing material to prevent adherence of the
roofing to the roof-deck and to isolate the roof-
ing from movements of the roof-deck.

dry shotcrete Concrete or mortar which is
pumped through two separate hoses and mixed;
one hose contains the dry materials and the
other contains water. The mixture is projected
through a nozzle at high velocity onto a surface.

dry sprinkler Same as dry-pipe sprinkler sys-
tem.

dry sprinkler system See dry-pipe sprinkler
system.

dry-stacked surface-bonded wall A wall
built of a combination of two or more masonry
units of different material bonded together, one
forming the backup and the other the facing of
the combination.

dry standpipe A standpipe that is not nor-
mally filled with water but to which water can
be supplied (through a fire department connec-
tion) in the event of fire.

dry standpipe system A standpipe system
that is normally dry.

dry steam See dry saturated steam.

dry stock See dry wood.

dry stone wall A wall composed of stones not
cemented with mortar.

dry strength The strength of an adhesive joint
determined immediately after drying under

specified conditions, or after a period of condi-
tioning in the standard laboratory atmosphere.

dry system See dry-pipe sprinkler system.

dry-tamp process The placing of concrete or
mortar by hammering or ramming a relatively
dry mix into place.

dry timber Timber from which all moisture has
been removed.

dry topping See monolithic surface treatment.

dry-type transformer A transformer whose
core and coils are not immersed in an insulating
oil.

dry vent A vent which carries neither water
nor waterborne wastes.

dry-volume measurement Measurement of
the ingredients of grout, mortar, or concrete by
their bulk volume.

dry wall 1. An interior wall, constructed with a
dry-wall finish material such as gypsum board or
plywood; also see dry construction. 2. In masonry
construction, a self-supporting rubble or ashlar
wall built without mortar.

dry -wall construction Same as dry construc-
tion.

dry -'wall finish An interior covering material
such as gypsum board or plywood, which is usu-
ally applied in large sheets or panels; does not
require a water additive to apply.

dry -'wall frame A type of knocked-down door-
frame; designed for installation in a wall which is
constructed with studs and a dry sheet facing
material (such as gypsum board) after the wall is
erected.

dry wall partition A partition constructed
without the application of wet plaster.

dry 'weight The dry density of a material multi-
plied by its volume.

dry 'well l.A covered pit either with open-
jointed lining or filled with coarse aggregate
through which drainage from roofs, basement
floors, foundation drain tiles, or areaways may
seep or leach into the surrounding soil. 2. Same
as cesspool. 3. An absorbing well.

dry wood l.(US) Wood dried to a moisture
content of from 15 to 19%. 2. (Brit.) Wood dried
to a moisture content of from 15 to 23%.

DS On drawings, abbr. for downspout.

D.S., D/S, D/Sdg Abbr. for drop siding.

343

DSGN

DSGN On drawings, abbr. for "design."

DT On drawings, abbr. for drum trap.

DT&G Abbr. for "double tongue and groove."

DU On drawings, abbr. for disposal unit.

dual duct A duct, having a continuous internal
divider, to provide two individual raceways for
installation of two separate electric wiring sys-
terns (such as one for electric power and one for
a sound system).

dual-duct system An air-conditioning system
in which two supply ducts run to each space
being conditioned, one for cold air, the other for
warm air; at each individually controlled space,
air from the two ducts is blended in a sheet-
metal box (called a "mixing box") and then sup-
plied to the conditioned space.

dual-duct terminal unit Same as "mixing
box"; see dual-duct system.

dual-element fuse A fuse which has current-
responsive elements of two different fusing char-
acteristics in series.

dual-fiber cable Optical fiber cable composed
of two single-fiber cables enclosed in an
extruded plastic overjacket; may have a rip cord
for peeling back the overjacket to access the
fibers.

dual-flush water closet A water closet pro-
viding a choice of two flushing mechanisms.
One button makes a full flush available; the
other uses only about half the amount of water.

dual-fuel system A heating system in which
the boiler can burn either of two fuels, usually
oil and gas in the US; usually one is the pri-
mary fuel and the other is used for standby pur-
poses.

dual glazing Same as double glazing.

dual-head nail Same as double-headed nail.

dual-pitched roof A roof having a double
slope on both sides of a central ridge; for exam-
ple, a gambrel roof.

dual-temperature system A hot water sys-
tem that supplies hot water at two different tem-
peratures.

dual vent, common vent, unit vent In
plumbing, a single vent, 1 connected at the
junction of two fixture drains, which serves as a
vent for both.

, ^-Common venl

r—f s

-•—Waste

dual vent

dub To strike, cut, rub, or dress so as to smooth
a surface.

dubbing out, dubbing 1. Filling in hollow
and irregular surfaces and leveling walls with
plaster before regular plasterwork. 2. Forming,
very roughly, a plaster cornice, before the final
plaster coat is applied.

duck See mouse.

duckboard 1 . A cat ladder. 2. A wooden walk-
way across muddy ground, a wet floor, etc.

duckfoot bend Same as rest bend.

duck tape A tape of heavy cotton or synthetic
fabric which is impregnated with a sealing com-
pound, such as asphalt or an elastomer.

duct l.See air duct. 2. In electric systems, a
metallic or nonmetallic tube, (usually circular,
oval, rectangular, or octagonal) for housing
wires or cables; may be underground or embed-
ded in concrete floor slabs.

duct fan See tubeaxial fan.

duct furnace A unit heater having a burner
and heat exchanger, but not a fan; located in a
duct system which is provided with a fan for
moving the air.

ductile Capable of being stretched or deformed
without fracturing.

ductile-iron pipe A pipe that is fabricated of a
cast-iron alloy in which graphite replaces the
carbon that is present in cast-iron; provides the
same advantages as cast-iron pipe along with the
added advantage of a higher external load-bear-
ing capacity; not as brittle as cast-iron pipe (thus
permitting rougher handling) but higher in cost.

ductility index The ratio of the total deforma-
tion at maximum load to the elastic limit defor-
mation.

duct lining A fiberglass blanket material used
as a lining inside a sheet-metal duct of an

344

dungeon

air-conditioning system; reduces noise which is
transmitted along the duct and provides thermal
insulation.
duct sealing compound A resilient sub-
stance used to seal the ends of a cable duct or
conduit.

duct sheet A coiled or flat sheet of a gauge
width and thickness suitable for use in duct-
work.

duct silencer Same as sound attenuator.

duct system A series of ducts and associated
elbows, connectors, dampers, and air outlets
used to convey air from a fan to the spaces
served.

ductwork The ducts in a heating, ventilating,
or air-conditioning system.

due care The standard of reasonable care, skill,
ability, and judgment which, if not met, consti-
tutes negligence; such a standard may be
imposed by contract or by operation of law in
the absence of a contract. This term implies the
performance of duties and services by a profes-
sional which is consistent with the level of per-
formance provided by reputable professionals in
the same geographical area at the same period of
time.

dugout A primitive shelter, often consisting of
an excavation in a bank of sloping terrain that is
roofed with bark laid over a pole framework,
then covered with sod; also see half-dugout.

dug well A well for water, constructed by exca-
vating a large-diameter shaft and installing a
casing.

dumbbell tenement A multiple-dwelling
substandard apartment building; commonly
three to five stories high, containing relatively
long narrow apartments within it; has windows
only at the front and rear of each apartment.
Shafts located on one or both sides of the apart-
ment provide air and a little light in the rooms
that do not face the front or rear of the building.
The floor plan of each floor resembles the out-
line of a dumbbell. Also called a railroad flat.

dumbwaiter A hoisting and lowering mecha-
nism within a building equipped with a rela-
tively small car which moves in a vertical
direction (in guides); used exclusively for carry-
ing materials.

dummy cylinder For a door lock, a mock
cylinder which has no operating mechanism.

dummy joint Same as groove joint.

dumped fill Excavated material, usually end-
dumped from trucks, with no special effort made
to spread or compact it.

dumpling A large unexcavated mass, usually at
the center of an excavated area, which is left
undisturbed; may be removed when the work
nears completion.

dump truck Any type of truck whose body can
be tilted to discharge its load.

dumpy level A surveying instrument used in
the direct measurement of differences of eleva-
tion; consists of a telescope and a spirit level
(which is parallel to the telescope and mounted
below it); the telescope is permanently attached
to leveling base.

EYEPIECE

-FOCUSING
KNOB

AZIMUTH
CLAMP

AZIMUTH
TANGENT
SCREW

dumpy level

dungeon l.The principal and strongest tower
of a castle; the keep. 2. A dim chamber in a
medieval castle, usually at the base of the keep.

dungeon, 1

345

dunnage

dunnage 1 . Pieces of timber which are used to
provide structural support for a large item of
equipment on a rooftop. 2. Members that form a
structural support for a cooling tower or the like,
but are not part of the building structure itself.

dunter machine See surfacer, 3.

duomo A cathedral; properly, an Italian cathe-
dral.

duomo at Brescia, shown in section

DUP On drawings, abbr. for "duplicate."
duplex l.A duplex apartment. 2. A duplex
house.

duplex apartment A separate dwelling in an
apartment building, having rooms on two levels,
with self-contained vertical circulation.

duplex burner In a heating system, a gas
burner having two sections which can either
burn together at full load or be used singly for
reduced heating.

duplex cable An electric cable consisting of
two individually insulated conductors which are
twisted together.

duplex-head nail Same as double-headed nail.

duplex house, two-family house A house
having quarters, with separate entrances, for two
families; usually a two-story house with a sepa-
rate apartment on each floor.

duplex outlet See duplex receptacle.

duplex receptacle In electric wiring, two
receptacles, combined as a single unit, for instal-
lation in an oudet box.

duplex receptacle

durability 1 . The ability of a material, compo-
nent, assembly, or building to resist weathering
action, chemical attack, abrasion, and other

conditions of service. 2. The resistance of a par-
ticular species of wood to decay.

durability factor A measure of the change
(with time) in the property of a material as a result
of exposure to an influence which has the poten-
tial of causing deterioration; usually expressed as a
percentage of the property before exposure.

duraluminum An alloy containing princi-
pally aluminum, approximately 4% copper, 0.2
to 0.75% magnesium, and 0.4 to 1% manganese;
individual manufacturers may include small
amounts of silicon and iron.

duramen See heartwood.

durbar In India, an audience hall in the palace
of a prince.

Durham fitting See drainage fitting.

Durham system A soil or waste system where
all piping is of threaded pipe, tube, or other such
rigid construction, using recessed drainage fittings.

durn A vertical member on each side of a door,
usually formed of a solid timber.

durometer An instrument for measuring the
degree of hardness of a material; also see shore
hardness.

dust board l.A panel placed above a built-up
cornice to prevent the entry of dust. 2. A pan-
eled division between wooden drawers.

dust collector An accessory device used to
prevent dust, which a tool or machine produces,
from escaping into the surrounding air; suction
forces the dust-laden air into a bag or chamber,
where it is collected.

dust cover box Same as plaster guard.

dust dry Same as dustfree.

dustfree Descriptive of the stage in the drying
of a paint or varnish film at which dust will no
longer stick to the surface.

dust-free time The time required for a freshly
applied paint or compound to form a skin on its
surface so that dust will not adhere to it.

dusting The development of a powdered mate-
rial at the surface of hardened concrete.

dust-laying oil Oil of sufficiently low viscosity
to be applied without preheating; may be a slow-
curing asphaltic product or a nonvolatile petro-
leum distillate containing no asphalt; applied
over unpaved surfaces.

346

Dutch diaper bond

dustproof So constructed or protected that the
accumulation of dust will not interfere with suc-
cessful operation.

dustproof strike A strike plate equipped with
a spring plunger that completely fills the bolt
hole when the bolt of the lock is not projected
into it.

dust»tight Descriptive of an enclosure which is
so constructed (with gaskets, etc.) as to prevent
the entry of dust.

Dutch arch, French arch A flat arch in
brick; most of the bricks slope outward from
the middle of the arch (at the same angle on
both sides of the centerline) and do not have
radial joints. Properly not an arch. Same as flat
arch.

Dutch barn l.A distinctive type of front-
gabled barn of curtain wall, 1 construction,
erected by early Dutch settlers in America;
approximately square in plan; built on stone
piers with a steeply pitched roof. Often
sheathed with overlapping planks to shed water
readily; the outer planks temporarily removable
for maintenance; typically had a small pent
roof directly over the entry way for wagons; owl
holes near the peaks of the gables for ventila-
tion and for access to the barn for mice-eating
birds. 2. Same as bank barn. 3. Same as hay
barrack.

Dutch bond 1. Same as English cross bond. 2.
Same as Flemish bond.

Dutch brick A hard yellow brick often used
in the interior of Dutch Colonial houses; com-
monly laid in the floor of the fireplace hearth
that extended into the room. Occasionally,
this term refers to a brick having a thickness of
only about VA inches (3.8 cm). Also see
klinkart.

Dutch Colonial architecture A broad term
describing the architecture prevalent in the
Dutch-settled parts of America during the early
part of the 17th century. The earliest houses
were simple one-story, single-room permanent
dwellings.

In rural areas, the design of houses depended
primarily on available building materials. Where
stone was abundant, houses were built with
thick stone walls; where suitable clay was avail-
able, houses were built of brick, usually laid in a

Flemish bond pattern; where timber was plenti-
ful, the houses were of wood construction with
siding of wide weatherboarding. Common char-
acteristics included: a roof covering of wood
shingles or tiles; steeply pitched gables with
parapets; Dutch gambrel roofs with flared eaves
having a considerable overhang; straight-line
gables; a chimney located in a thick exterior wall
at a gable end or gambrel end of the house; case-
ment windows with small panes and battened
shutters; a Dutch door; heavy plank floors, bake
ovens.

In urban areas such as New Amsterdam,
houses were typically two and a half or three
and a half stories high, although those in which
the owners also conducted a business on the
ground floor and lived in the floors above were
four or five stories high. Common characteris-
tics included: thick exterior walls usually hav-
ing a rough timber structure, faced with a brick
veneer laid in a Flemish bond pattern with the
facing secured to the timber framing by decora-
tive wrought-iron anchors; where wood was
plentiful, wide weatherboarding used as siding
instead of brick facing; stone walls in regions
where stone was commonly available; a para-
peted gable-end wall often facing the street;
typically, corbie gables or steeply pitched
straight-line gables; often, a gambrel roof with
flared eaves; usually, a brick chimney within
the exterior walls, topped with a chimney cap;
casement windows with small glass panes in
cames; battened shutters (later replaced by
double -hung windows); a Dutch door or pan-
eled double door, often with a transom light
above; usually an exterior stoop in front of the
door.

Dutch Colonial Revival Revival architec-
ture from the late 19th century onward, loosely
based on the Dutch Colonial prototypes
described previously, including a gambrel roof,
flared eaves, Dutch doors, and multipaned
double-hung windows. Revival houses often
retain many of the characteristics of their proto-
types, but differ significantly as a result of modern
additions such as a gambrel roof with dormers,
wood shutters having decorative designs cut
through the shutters, and cross gambrels.

Dutch diaper bond Same as English cross
bond.

347

Dutch door

Dutch door A door consisting of two separate
leaves, one above the other; the leaves may
operate independently or together.

fc-.-A-

Dutch door: exterior elevation; interior elevation

Dutch door bolt A device which fastens
together the upper and lower leaves of a Dutch
door so that they open and close as a single unit.

Dutch dormer See shed dormer.

Dutch gable l.Same as Flemish gable. 2. A
corbie gable.

Dutch gambrel roof A type of gambrel roof

that has two flat surfaces on each side of the
ridge of the roof. The initial downward slope
from the roof ridge is an angle of about 22 degrees,
then steepens to an angle of about 45 degrees.
Near the lower end, the pitch is much less and
the roof has flared eaves. Compare with English
gambrel roof, New England gambrel roof,
Swedish gambrel roof.
Dutch kick A roof having flared eaves, as in a
Dutch gambrel roof.

Dutch lap A method of applying shingles,
slates, etc.; each shingle overlaps one below and
one to the side.

Dutch lap

Dutch light A removable glazed sash, used in
greenhouses.

dutchman 1. A small piece or wedge inserted
as filler to stop an opening. 2. A small piece of
material used to cover a defect, to hide a badly
made joint, etc. 3. A short lead nipple used to
join two pipes which are otherwise not long
enough to be joined.

Dutch method of application A method of
applying rectangular roofing shingles which pro-
vides a lap at the top and one side, thereby form-
ing a square or rectangular pattern.

Dutch oven Same as bake oven.

Dutch roof Occasionally, a synonym for a
Dutch gambrel roof.

Dutch shutter A shutter, 2 whose upper and
lower sections can be opened and closed inde-
pendently of each other.

Dutch slice-hip roof A Dutch gambrel roof
in which each end has been clipped off, as in a
jerkinhead roof.

Dutch slice-hip roof

Dutch stoop A small wooden porch having a
wood bench along each side of the entry door;
may be covered by a cantilevered hood.

Dutch tile A flat, square, decorative tile from
Holland often used on the faces of fireplaces; dif-
ferent colors were once available, but Delft blue
tiles were probably the most popular.

348

dyostyle

DVTL On drawings, abbr. for dovetail.

dwang l.A crowbar or similar tool. 2. A strut
inserted between timbers to stiffen them.

dwarf door A door whose height is somewhat
less than normal.

dwarf gallery A passage on the external sur-
face of a wall screened by a small-scale arcade.

dwarf partition A partition which does not
extend to full ceiling height.

dwarf rafter Same as jack rafter.

dwarf wainscoting Wainscot that is restricted
to the lower part of a wall.

dwarf wall 1. A wall of less height than a story
of a building. 2. A wall which supports the
sleeper joists under the lowest floor of a building.

dwelling A building designed or used as the liv-
ing quarters for one or more families.

dwelling unit One or more rooms in a building
designed as living accommodations for one or
more families.

dwg, DWG Abbr. for "drawing."

D»window l.Same as semicircular fanlight. 2.
A semicircular window, 2.

DWV Abbr. for "drainage, waste, and vent."

DWV tubing See type-DWV tubing.

dye A coloring material or compound that
imparts color throughout a material by penetra-
tion.

dyke See dike.

Dymaxion House An unconventional light-
weight house developed and patented in 1928 by
R. Buckminster Fuller (1895-1983); originally
called the 4-D house, and intended as a prefabri-
cated unit. Octagonal or circular in plan, this
experimental house was supported by a massive
central shaft that housed all building services,
such as electrical and plumbing systems.

dynamic Said of a structure whose physical
behavior characteristics are time-related, i.e.,
are nonstatic.

dynamic analysis The analysis of a structural
system as a function of displacement under tran-
sient loading conditions.

dynamic balancing See balancing.

dynamic load Any load which is nonstatic,
such as a wind load or a moving live load.

dynamic loading Loading by a piece of
machinery or equipment which imposes a load
in addition to its static load, as a result of its
vibration or movement.

dynamic modulus of elasticity The modu-
lus of elasticity of a test specimen which is com-
puted from physical characteristics of the
specimen (size, weight, and shape) and from its
fundamental frequency of vibration.

dynamic penetration test A penetration test
in which penetration into the soil results from
the application of a series of blows on a testing
device.

dynamic pile formula Any of several formu-
las by which the bearing capacity of a driven pile
can be calculated from the energy of the pile
hammer and the penetration of the pile under
each blow.

dynamic pressure The pressure on the inner
surface of a pipe when water flows through it;
this pressure is in excess of that when the water
is at rest.

dynamic resistance The resistance of a pile
(or the like) to blows from a pile hammer,
expressed in blows per unit depth of penetration.

dynamics That part of the science of mechanics
which treats the motion of bodies and the action
of forces in producing or changing their motion.

dyostyle Same as distyle.

349

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E Symbol for "90° elbow."

E/A Abbr. for "engineer/architect."

EA Abbr. for "exhaust air."

eachea One of a number of earthen or bronze
vases described by Vitruvius as being installed
under the seats of open-air theaters for "reinforc-
ing" the voices of the actors; it is doubtful that
such vases were employed.

eagle A pediment of a Greek building.

E&CB1S Abbr. for "edge and center bead one
side."

E&CV1S Abbr. for "edge and center vee one
side."

E and OE Abbr. for "errors and omissions
excepted."

ear 1. Any small projecting member or part of a
piece or structure, either decorative or struc-
tural. 2. See shoulder, 1. 3. Same as crossette, 1.

eared architrave Same as crossette.

EAR lamp An incandescent lamp part of
whose envelope acts as an ellipsoidal reflector;
used with small-aperture downlights.

earliest event occurrence time In CPM ter-
minology, the earliest point in time that all activ-
ities that precede the event will be completed.

Early American See American Colonial
architecture.

Early Christian architecture The final phase
of Roman architecture from the 4th to the 6th
cent., primarily in church building. Coeval with
and related to the rise of Byzantine architecture.

Early Classical Revival Occasionally, a syn-
onym for the Classical Revival style, which was
popular in America from about 1770 to 1830;
the addition of the adjective Early is intended to
differentiate this style from Neoclassical style, a
later reuse of classical architecture between
about 1895 and 1940.

Early English Colonial architecture See
American Colonial architecture.

Early English style The first of the three
phases of English Gothic architecture, from ca.

Early English style: Westminster Abbey

Early English style: window

Early English style: base

351

early finish time

1 180 to ca. 1280, based on Norman and French
antecedents and succeeded by the Decorated
style. Often characterized by lancet windows
without tracery.

early finish time In CPM terminology, the first
day upon which no work is to be done for an activ-
ity assuming that it started on its early start time.

Early Gothic Revival See Gothic Revival.

Early Romanesque Revival A term occa-
sionally used for Romanesque Revival, 2.

early start time In CPM terminology, the first
day of the project, upon which work on an activ-
ity can begin if every preceding activity is fin-
ished as early as possible.

early stiffening See false set.

early strength The strength of concrete or
mortar developed soon after placement, usually
during the first 72 hr.

Early Victorian See Victorian architecture.

earlywood See springwood.

earth 1. British term for ground, 3.2. See soil, 1.

earth auger An auger, 2.

earth berm See berm.

earth building Same as sod house.

earth cellar A cellar that is dug into the face of
steeply sloping ground, with its floor at approxi-
mately the same level as the ground at the
entrance door; provides an effective place for
storing food because the surrounding earth keeps
the interior cool. Compare with root cellar.

earth dike Same as dike, 4.
earth drill Same as auger, 2.

earth electrode In electric wiring a metal
plate, water pipe, or other type of conductor
buried in the earth in a manner ensuring a good
conductive path to the ground.

earthenware 1 . A glazed or unglazed nonvitre-
ous ceramic whiteware, having an absorption of
more than 3%. 2. See stoneware.

earthfast Descriptive of a timber-framed struc-
ture that is supported on posts sunk in the ground,
rather than supported by a foundation; also see
post-in-ground construction and poteaux-enterre
house.

earth floor In many types of primitive dwellings,
a floor providing a reasonably durable walking
surface, and that was usually composed of a

compacted mixture of earth, ashes, clay (if avail-
able), with additives such as lime, pebbles, or
straw. Another addition — animal blood — was
once thought to improve the stability of the com-
pacted soil. Also see rammed earth.

earthing conductor British term for ground-
ing electrode conductor.

earthing lead British term for grounding con-
ductor.

earth material Any rock, fill, natural soil, or
combination thereof.

earth pigment, mineral pigment, natural
pigment A pigment which is produced by
physical processing of materials mined directly
from the earth.

earth plate 1 . An earth electrode in the form of
a buried metal plate. 2. British term for buried
plate electrode.

earth pressure 1. The horizontal thrust which
is exerted by retained earth. 2. The pressure
exerted on a structure, such as a wall, by the
earth which it retains.

earthquake load The total force exerted on a
structure by an earthquake.

earth roof See sod roof.

earth-sheltered construction A building in
which at least 50% of the combined area of the
walls and roof are covered with a thick layer of
earth.

earth table Same as ground table.

earth-wall dwelling See jacal, pueblo archi-
tecture, sod house.

earthwork 1. Operations connected with the
movement of earth. 2. A construction made of
soil.

ease A curve at the lower end of a handrail, where
it meets the newel post that supports the handrail.

eased Said of a building component, any edge of
which is slightly rounded, for example, as a stair
nosing.

eased edge Any edge which is rounded slightly.

xids

s£

eased edge

easement 1. A right of accommodation (for a
specific purpose) in land owned by another, such
as right-of-way or free access to light and air.

352

eaves bracket

2. A curve formed at the juncture of two members;
forms a smooth transition between surfaces that
would otherwise intersect at an angle. 3. Those
portions of stair handrails which are curved in the
vertical plane only; an "easement curve."

easing 1. Removal of material to enable a piece
to be fitted into an allotted space. 2. See base-
ment, 2.

east end The end of a church where the principal
altar is placed; so called because medieval
churches almost invariably had their sanctuaries
at the east end and the main doors at the west end.

Eastern closet Same as Asiatic water closet.

eastern crown See antique crown.

eastern hemlock, hemlock spruce, spruce
pine Wood of a coniferous tree of eastern
North America; moisture-resistant, soft, coarse,
uneven-textured; splinters easily; inferior for use
in construction.

Eastern method See pick and dip.

eastern red cedar, aromatic cedar A highly
aromatic, moderately high-density, fine-textured
wood of a distinctive red color with white
streaks; widely used for fence posts, shingles, and
mothproof closet linings.

Eastern Stick style Same as Stick style; also
see Western Stick style.

eastern water closet Same as Asiatic water
closet.

Easter sepulcher In some churches, in which
sacred elements are placed from Maundy Thursday

to Easter, an embrasure on the left wall of the
chancel.

East Indian laurel A dense, moderately hard
wood; light to dark brown in color, with dark
streaks; found in India and Burma. Used for cab-
inets, paneling, and interior finish; resembles
black walnut.

East Indian rosewood A hard, dense wood;
purplish in color, with black streaks; used for
decorative paneling and cabinets.

Eastlake ornamentation, Eastlake style
A style not of architecture but of ornamenta-
tion, associated with the English designer
Charles Locke Eastlake (1836-1906). Decora-
tive elements included: spindlework (espe-
cially balusters or posts turned on a lathe),
perforated bargeboards and pediments, carved
panels, large ornamental fanlike brackets,
highly ornamental moldings, and decorative
hardware fittings such as door knobs and
locks.

east 'window In church architecture, a window
at the choir end of the church, which is com-
monly the east end.

eave lead A lead gutter, 1.

eaves That part of a roof that projects beyond
the exterior wall; usually the lower edge of a
sloped roof. Also see bellcast eaves, boxed eaves,
bracketed eaves, closed eaves, coved eaves,
flared eaves, open eaves.

eaves board Same as eaves fascia.

eaves bracket A bracket that supports the
eaves of a roof; usually one of many, often in
pairs.

Easter sepulcher

eaves brackets

353

eaves channel

eaves channel A channel or small gutter
along the top of a wall; conveys the roof drip-
pings to spouts or gargoyles.

eaves cornice A cornice at the eaves of a roof.

eaves course 1 . The first course of slates, shin-
gles, or tiles at the eaves on a roof. 2. Same as
double course.

eaves fascia A board that is nailed vertically at
the ends of roof rafters; sometimes supports a
gutter; also called a fascia board.

eccentric Not having the same center or center
line.

eaves fascia

eaves flashing A metal strip which is dressed

into an eaves gutter, acting as flashing,
eaves gutter See gutter, 1.

eaves lath A strip of wood beneath the lowest
course of shingles on a roof (i.e., at the eaves)
that raises the lower edges of the shingles so they
are nailed at the same slope as the shingles above
them.

eaves plate A horizontal wood beam, at the
eaves, which is supported at its ends by piers or
posts; carries the lower ends of roof rafters.

eaves pole A cant strip.

eaves soffit The horizontal surface under pro-
jecting eaves.

eaves tile, starter tile Tile, usually shorter or
plainer than the other roofing tile, used in the
first course of tile along the eaves of a building.

eaves trough See gutter, 1.

EB1S Abbr. for "edge bead one side."

ebonize To blacken with paint or stain to look
like ebony.

ebony Wood of a number of tropical species
usually distinguished by its dark color, durability,
and hardness; used for carving, ornamental cab-
inetwork, etc.

eccentric head and shaft

eccentric-braced frame A frame whose cen-
terline braces are offset from the intersection of
the centerlines of the columns and beams.

eccentric fitting Any fitting, 1 in which the
center line is offset from that of the run of pipe.

eccentric load A load on a column or pile
which is nonsymmetric with respect to the cen-
tral axis, therefore producing a bending moment.

eccentric tendon In prestressed concrete, a
tendon which follows a trajectory not coinci-
dent with the gravity axis of the member.

ecclesiology The study of the furnishing and
adornment of churches.

echauguette A bartizan.

echinus The convex projecting molding of
eccentric curve supporting the abacus of the Doric
capital. Hence the corresponding feature in capi-
tals of other orders, which often had egg-and-dart
ornamentation; any molding of similar profile or
decoration. Also see ovolo, bowtell.

chi

echinus:

echinus and astragal An ornament similar to
egg and dart with a bead and reel below it.

echinus and astragal at the Pantheon

354

edge plate

echo Sound waves which have been reflected to
a listener with sufficient magnitude and time
delay so as to be perceived separately from those
communicated directly to the listener.

eclectic architecture Architecture that com-
bines elements and characteristics of a wide range
of historic styles. See Exotic Eclectic architecture,
French Eclectic architecture, Neo-Eclectic archi-
tecture, Spanish Eclectic architecture.

Eclecticism The selection of elements from
diverse styles for architectural decorative
designs, particularly during the second half of
the 19th cent, in Europe and the US.

Ecole des Beaux-Arts The school in Paris
that taught elaborate, historic, and eclectic archi-
tecture, designed on a monumental scale, based
on classical architecture of Hellenic Greece and
Imperial Rome, that adapted features of French
architecture of the 16th, 17th, and 18th cen-
turies; became a State institution in 1863 and still
is the center of the teaching of architecture in
France. Also see Beaux-Arts style.

economic rent That rent on a property which
is sufficient to pay all costs of operation, mainte-
nance, and payment of mortgages (but not utili-
ties and services).

economy brick A cored, modular brick whose
nominal dimensions are 4 in. by 4 in. by 8 in.
(10.16 cm by 10.16 cm by 20.36 cm); actually
about VA in. by 3M in. by TA in. (8.89 cm by 8.89
cm by 19.05 cm).

economy-grade lumber The lowest grade of
lumber; intended for work where price is the pri-
mary consideration. Compare with custom-
grade lumber and premium-grade lumber.

economy wall A brick wall, 4 in. (10 cm)
thick, back-mortared and strengthened at inter-
vals by vertical pilasters to support floor or roof
framing.

ecphora The projection of any member or
molding beyond the face of the member or
molding directly below it.

ectype A copy or image in relief or embossed.

eddy flow See turbulent flow.

edge-bar reinforcement In concrete con-
struction, tension steel used as reinforcement to
strengthen insufficiently strong edges of a con-
crete slab.

edge bead See corner bead.

edge beam A stiffening beam at the edge of a
slab.

edge-bedded See face-bedded.

edgebend British term for crook, 1 .

edge clearance The distance between the edge
of a pane of glass or a panel and its surrounding
frame, measured in the plane of the pane or
panel.

edge isolation Same as expansion strip.

edged tool See edge tool.

edge form A form to limit the horizontal spread
of the freshly poured concrete on a flat surface or
slab.

edge-glued core See continuous block core.

edge-grained, comb-grained, quartersawn,
rift-grained, vertical-grained Descriptive
of wood sawn so that the annual rings intersect
the wide face at an angle of 45° or more.

edge-grained

edge joint l.A joint formed between two
veneers or laminations, in the direction of the
grain. 2. A joint formed between two boards or
plates which are side-by-side.

edge joint, 2 (welded)

edge molding, edging, edge strip Any

molding on the edge of a door, counter, or other
relatively thin member.

edge nailing, edge toenailing Nailing
through the edges of boards, such as flooring, so
that each board conceals the nailing in the
adjacent one.

edge plate On a door, an angle iron or a channel-
shaped guard used to protect the edge of a door.

355

edge pull

edge pull A pull which is mortised into the

edge of a sliding door.
edger 1 . A finishing tool used on the edges of

fresh concrete or plaster to provide a rounded

corner. 2. A wood sanding machine for use along

the edges of wood floors.

edger, 1

edge roll See bowtell.

edge set Descriptive of brick which is laid on its

narrow side rather than its flat side.
edge shafts Shafts which sustain arches, united

by their sides and back to the nearest wall or

arch, so they appear to support their edge only;

abundantly used in Norman architecture.

edge shafts

edge-shot Planed on the edges, as a board.

edge spacer In window construction, a spacer
which (a) prevents edge contact and (b) posi-
tions laterally a pane of glass or panel within a
supporting frame.

edgestone A stone used for curbing.

edge toenailing See edge nailing.

edge tool, edged tool Any tool having a
sharp cutting edge, such as a plane or chisel.

edge tracking In painting with a roller, the
trails that may result from either or both ends of
the paint roller.

edge vent One of the openings at the perimeter
of a roof to relieve possible water-vapor pressure
in the roof system.

edging l.Edge molding. 2. A plain or molded
strip of metal, wood, or other material used to
protect edges of a panel or hide the laminations
as in plywood or roof sheathing; an edging strip.
3. In concrete finishing, the process of rounding
the exposed edges of slabs to reduce the possibil-
ity of chipping or spalling.

SHINGLES

edging strip Same as edging, 2.
edging trowel Same as edger, 1.
edicule An aedicula.

edifice A large and important building.

Edison-base fuse A fuse rated up to 30 amperes,
contained in a small glass or ceramic container
that screws into a socket; has a window for observ-
ing whether the fuse has "blown."

Edison screw A threaded metal base for an
incandescent lamp.

EDR Abbr. for "equivalent direct radiation."

educational occupancy The use of a building
or buildings for the gathering of groups of six or
more persons for purposes of instruction, includ-
ing schools, universities, colleges, academies,
nursery schools, and kindergartens.

EE 1. Abbr. for "eased edges." 2. Symbol for "45°
elbow."

eelgrass An organic material composed of a
dried grass-like sea plant; fabricated as a blanket,
usually enclosed by kraft paper; the resulting
enclosed air spaces provide resistance to heat
flow; has been used as a thermal insulator.

356

eggcrate diffuser

effective area The net area of an air outlet or
air inlet through which air can pass; it is equal to
the free area of the device times the coefficient
of discharge.

effective area of reinforcement In rein-
forced concrete, the product of the right cross-
sectional area of the steel reinforcement by the
cosine of the angle between its direction and the
direction for which its effectiveness is considered.

effective bond A bond in brickwork which is
completed at the ends with a 2M-in. (5-cm) closer.

effective depth Of a beam or slab section, the
depth measured from the compression face to
the centroid of the tensile reinforcement.

effective flange width The depth of a beam
or section of a slab.

effective length Of a column, the distance
between inflection points in the column when it
bends.

effective opening The minimum cross-sectional
area of the opening at the point of water-supply dis-
charge, expressed in terms of diameter of a circle; if
the opening is not circular, the diameter of a circle
of equivalent cross-sectional area is given.

effective prestress The stress remaining in
concrete due to prestressing after loss of prestress;
includes the effect of the weight of the member,
but excludes the effect of any superimposed load.

effective reinforcement That reinforcement

which is assumed to be active in resisting applied

stresses.
effective span The distance (measured from

center to center) between supports for a beam,

or the like.

effective stress In prestressed concrete, the
stress remaining in the tendons after loss of pre-
stress has occurred.

effective temperature An index which com-
bines into a single figure the effects of temperature,
humidity, and air movement on the sensation of
warmth or cold felt by the human body; numeri-
cally equal to the temperature of still, saturated air
which induces an identical sensation.

efficacy See luminous efficacy.

efficiency apartment A small apartment usu-
ally consisting of a single room used both as a liv-
ing room and as a bedroom, together with a
kitchen alcove and a bathroom.

efficiency ratio The ratio of the net usable
area of a building to its gross floor area.

effigy A representation or imitation of a person,
in whole or in part, as a likeness in sculpture.

efflorescence An encrustation of soluble salts,
commonly white, deposited on the surface of
stone, brick, plaster, or mortar; usually caused
by free alkalies leached from mortar or adjacent
concrete as moisture moves through it.

effluent In sanitary engineering, a liquid which
is discharged as waste, esp. the discharge from a
septic tank.

effluent discharging into soil

EG Abbr. for "edge (vertical) grain."

e.g. Abbr. for the Latin term "exempli gratia,"

which means for example .
egg and dart, echinus, egg and anchor, egg
and arrow, egg and tongue An egg-shaped
ornament alternating with a dart-like ornament,
used to enrich ovolo and echinus moldings and
also on bands. In the egg-and-anchor, egg-and-
arrow, and egg-and-tongue moldings, the dart-
like ornament is varied in form.

egg and dart

egg-and-tongue molding Same as tongue-
and-egg molding.

eggcrate diffuser A metal or plastic assembly,
resembling an eggcrate, used below a lighting
fixture to diffuse the light it provides.

357

eggcrate louver

eggcrate louver A louver having rectangular
openings resembling the dividers used in egg
containers.

eggshell, eggshelling A semimatte glaze or
porcelain enamel surface resembling eggshell in
texture; sometimes a defect.

eggshell gloss Low gloss of a paint film;
slightly higher in gloss than a flat or matte finish
but lower than a semigloss.

eggshelling See chip cracks.

egress An exit, or means of exiting. Also see
means of egress.

Egyptian architecture The architecture of
Egypt from the 3rd millennium B.C. to the
Roman period. Its most outstanding achieve-
ments are its massive funerary monuments and
temples built of stone for permanence, featuring
only post-and-lintel construction and corbel
vaults without arches and vaulting.

Egyptian door A door whose frame is nar-
rower at the top than at the bottom, with door-
jambs that are inclined inward at their tops with
respect to the vertical.

Egyptian gorge, cavetto cornice The char-
acteristic cornice of most Egyptian buildings,
consisting of a large cavetto decorated with ver-
tical leaves, and a roll molding below.

Egyptian Revival A mode of Exotic Revival

architecture suggestive of the architecture of
ancient Egypt; used primarily from about 1800 to
1850 and then again, though rarely, from about
1920 to 1930. Buildings in this style usually

Egyptian gorge

Egyptian architecture: above, facade of Temple of Horus; right, column, Temple of Hathor

358

elbow

include some of the following characteristics
and/or decorative elements: ashlar-finished exte-
rior walls that are tilted inward at their tops with
respect to the vertical; window frames that are
narrower at the top than at the bottom; Egyptian
doors; lotus capitals; columns that bulge or that
imitate papyrus stalks bundled by bands at the top
and bottom of the columns; an Egyptian gorge;
winged sun disks; an entrance portal flanked by a
monumental gateway having slanting sidewalls.

EIC Abbr. for "Engineering Institute of Canada."

EIFS Abbr. for exterior insulation and finishing
system.

EIS Abbr. for "environmental impact statement."

ejector, ejector pump 1. A type of pump for
ejecting liquid, as from a sump; induces fluid flow
by entraining the liquid in the flow of a stream of
air, steam, or water. 2. A cleanout, 1.

ejector basin A receiving basin that collects
sanitary waste discharge.

ejector grille (Brit.) l.A ventilating grille
with slots shaped to force the air out in divergent
streams. 2. A British term for an air diffuser.

ejector vent A vent pipe used to convey air to
a receiving basin that collects sanitary waste dis-
charge.

EL On drawings, abbr. for elevation.

el See ell.

elaeothesium Same as alipterion.

elastic Descriptive of a material having the
property of elasticity.

elastic arch An arch designed on the basis of
the elastic theory of materials.

elastic constant l.See modulus of elasticity.
2. See Poisson's ratio.

elastic deflection The deflection of a structural
element when a load is applied to it, and which
recovers when the load is removed, as opposed to
the deflection resulting from creep, 1 .

elastic deformation A change in shape without
impairment of the elastic properties of a material.

elastic design A method of analysis in which
the design of a structural member is based on a
linear stress-strain relationship, assuming that
the working stresses are only a fraction of the
elastic limit of the material.

elasticity The property of a body that causes it
to tend to return to its original shape after defor-
mation (as stretching, compression, or torsion).

elastic limit The greatest stress which a mate-
rial is capable of sustaining without permanent
deformation upon complete release of the stress.

elastic loss In pretensioned concrete, the reduc-
tion in prestressing load resulting from the elastic
shortening of the member.

elastic modulus Same as modulus of elasticity.

elastic shortening l.In a structural member,
a decrease in the length (under an imposed load)
which is linearly proportional to the load. 2. In
prestressed concrete, the shortening of a mem-
ber which occurs immediately on application of
forces induced by prestressing.

elastomer A macromolecular material (such as
rubber or a synthetic material having similar
properties) that returns rapidly to approximately
the initial dimensions and shape after substan-
tial deformation by a weak stress and release of
the stress.

elastomeric Said of any material having the
properties of an elastomer, as a roofing mate-
rial which can expand and contract without
rupture.

elastomeric bearing An expansion bearing
fabricated of an elastomer, which permits move-
ment of the structure it supports.

elbow l.A pipe, sheet metal, or conduit fitting
having a bend, usually 90°; a 90° elbow is also
called an ell. 2. A crossette, 1. 3. A shoulder, 1.

PIPE

90°

REDUCING

PIPE TO TUBE (90°)

FEMALE MALE

COPPER TO COPPER

45° 90°

elbows, 1

359

elbow-action tap

elbow-action tap A faucet having a water
outlet valve whose flow is controlled by the pres-
sure of an arm or elbow.

elbowboard 1. An elbow rail. 2. Same as win-
dow stool.

elbow catch A spring-loaded locking device
commonly used to lock the inactive leaf of a
pair of cabinet doors. When the inactive leaf
closes, a hook on one end of the catch auto-
matically engages a strike, thereby securing the
door.

elbow rail A strip of millwork fixed to a parti-
tion as an armrest; also called an elbowboard.

elec, ELEC Abbr. for electric or electrical.

electric box Same as box, 2.

electric, electrical The qualifying adjectives
electric and electrical have the following mean-
ings: containing, producing, arising from, actu-
ated by, or related to electricity. In general,
electric is used when the term being qualified
designates something that has the properties,
dimensions, or physical characteristics associ-
ated with electricity; electrical is used when the
term being qualified does not explicitly desig-
nate something that has the properties, dimen-
sions, or physical characteristics of electricity
(e.g., electrical engineering). However, some-
times these two terms are used interchange-
ably.

electric filament lamp Same as incandescent
lamp.

electric riser Same as riser, 5.

electric strike plate A remote-controlled
strike plate.

electrical codes See National Electrical Code
(NEC) and National Electrical Safety Code
(NESC).

electrical conductivity A measure of the
ability of a material to conduct electric current.

electrical conduit Same as conduit, 1.

electrical curing The curing of concrete by
the use of electrical heaters.

electrical distribution cutout See distribu-
tion cutout.

electrical fault See fault.

electrical insulation, insulating material
A material that is a very poor conductor of elec-
tricity.

electrical insulator A component or device
made from material having great enough resis-
tance to the flow of electric current to be effec-
tively considered as a nonconductor of current.

electrically supervised Descriptive of an
electric wiring system which utilizes the flow of a
small current in the circuit (too small to actuate
the apparatus being supplied) to energize an
alarm signal upon failure of any device or equip-
ment in the circuit.

electrical metallic conduit (EMC) Con-
duit, usually fabricated of steel, which encloses
electrical wiring, thereby protecting the wiring
from outside damage. The difference between
electrical metallic conduit and electrical metallic
tubing (EMT) is that conduit is heavy-walled
and usually has threaded ends; in contrast, tubing
is thinner and is not threaded. Between these
two is an intermediate metallic conduit (IMC),
which is 25 percent lighter and less costly than
EMT; it may be threaded or threadless.

electrical metallic tubing A thin-walled
metal raceway having a circular cross section;
used to pull in or withdraw electric cables or
wires after the tubing is installed in place; uses
connectors and couplings other than the
threaded type.

electrical nonmetallic tubing (ENT) A
round, corrugated plastic tube that is concealed
in concrete, or it may be concealed in a ceiling
construction having a fire rating of at least
15 minutes, provided the ceiling is not used as a
plenum for return air.

electrical porcelain Vitrified whiteware hav-
ing an electrical insulating function.

electrical resistance The physical property of
a device, conductor, element, branch, or system,
by virtue of which power is lost as heat when
current flows through it; the physical property
which an electric conductor exhibits to the flow
of current; measured in ohms.

electrical resistivity, specific resistance

The resistance, in ohms, of an electric conductor
of unit cross-sectional area and unit length.
electrical rod Obsolete term for lightning rod.

electrical service connection See service
connection.

electrical tape See friction tape, thermoplastic
insulating tape, thermoplastic protective tape.

360

electrolier

electric appliance See appliance.
electric-arc welding See arc welding.
electric blasting cap A blasting cap designed

for and capable of detonation by means of an

electric current.

electric cable See cable, 1 and cable, 2.

electric cord One or more flexible insulated
electric conductors in a flexible insulating cov-
ering which is equipped with terminals.

electric -delay blasting cap A cap designed
to detonate at a predetermined time after elec-
trical energy is applied to the ignition system.

electric device See device.

electric-discharge lamp A lamp which pro-
duces light when electric current flows through a
vapor or a gas; may be designated by the gas fill-
ing which is responsible for the major part of the
radiation (e.g., mercury lamp, neon lamp, etc.),
by the physical dimensions or operating parame-
ters (e.g., short-arc lamp, high-pressure lamp,
etc.), or by its application (e.g., black-light
lamp, bactericidal lamp, etc.).

electric drill A hand-held electrically powered
drill, 1; usually classified according to the capac-
ity of the chuck; may be of either fixed or vari-
able speed.

electric eye See photoelectric cell.

electric heating element A unit consisting
of an electrical resistance material, insulated
supports, and terminals for connection to a
source of electric power; used as a heat source.

electricity meter A device which measures
and registers the integral of an electric quantity
with respect to time, e.g., a watt-hour meter.

electric lock A locking device in which the
movement of a bolt or latch is actuated by the
application of a voltage to the terminals of
the device.

electric motor control See motor controller.

electric operator An electrically powered
mechanism used to open or close a casement
window, hatch, damper, or the like.

electric outlet See outlet.

electric panel heating See panel heating.

electric precipitator Same as electrostatic
precipitator.

electric receptacle See receptacle.

electric resistance welding See resistance
welding.

electric sign A fixed or portable self-contained,
electrically illuminated appliance with words or
symbols designed to convey information or
attract attention.

electric space heater A space heater in

which electricity supplies the heat energy.

electric squib An electrically actuated device
used to ignite a charge in blasting operations.

electric stairway Same as escalator.

electric strike An electrical device that per-
mits the release of a door at a remote location.

electric water heater A water heater, usually
fully automatic, having a storage tank with one
or more electric heating elements, and with
operating and safety controls.

electric welding l.See arc welding. 2. See
resistance welding.

electroacoustics The science of transforming
acoustical energy into electric energy and vice
versa, e.g., by means of microphones or loud-
speakers.

electrochemical corrosion Same as gal-
vanic corrosion.

electrocopper glazing See copperlight glazing.

electrode 1. In arc welding, the component in
a welding circuit through which an electric cur-
rent is conducted between the electrode holder
and the arc. 2. In resistance welding, the compo-
nent through which the electric current in the
welding machine passes (usually accompanied
by pressure) directly to the work.

electrode hot-water heater A domestic hot-
water heater that is heated by an electric current
flowing through enclosed electrodes submerged
in the water tank. Also see instantaneous-type
water heater.

electrogalvanizing Galvanizing by a process
in which the zinc is deposited by an electroplat-
ing method.

electrogas welding A method of gas metal-
arc welding or flux-cored arc welding in which
an external gas is supplied; for welding in a ver-
tical position, the molding weld is confined by
"welding shoes."

electrolier A support for an electrically operated
luminaire, esp. one that hangs, as a chandelier.

361

electroluminescence

electroluminescence The emission of light
from a phosphor excited by electromagnetic
energy.

electroluminescent lamp A lamp in the
form of a thin sheet, either rigid or flexible,
which generates light by electroluminescence;
characterized by low luminance and efficacy.

electrolysis The decomposition of a chemical
compound into its constituent parts by the pas-
sage of an electric current; this action leads to
the decomposition of metals.

electrolytic copper Copper that has been
refined by electrolytic deposition; used for man-
ufacture of tough pitch copper and copper alloys.

electrolytic corrosion Same as galvanic cor-
rosion.

electrolytic protection See cathodic protec-
tion.

electromagnetic contactors Electrically actu-
ated devices to open and close electric power
circuits.

electromagnetic interference In the trans-
mission or reception of communication signals,
the interference caused by the radiation of elec-
tromagnetic fields.

electromotive force The force which causes
(or tends to cause) the movement of electricity
in a conductor; the difference in potential
between the terminals of an electric source.

electroplated Said of a metal surface having a
thin electrochemical deposit of a metal such as
brass, zinc, copper, cadmium, tin, or nickel; the
metal deposit usually is the result of its immer-
sion in an electrolytic bath.

electroslag welding A welding process in which
the two surfaces to be welded are fused together by
use of an electrically liquefied molten slag which
melts both the filler metal and the two surfaces.

electrostatic air cleaner Same as electrosta-
tic precipitator.

electrostatic filter An electrostatic precipi-
tator.

electrostatic paint-sprayer An electrically
operated paint spray-gun in which an electric
potential difference is established between the
atomized paint particles and the item being
sprayed. As a result, the paint particles are
attracted to the item being sprayed, thereby pro-
viding a clean paint job.

electrostatic precipitator A device installed
in flues, and the like, to prevent smoke and dust
particles from escaping to the atmosphere; the
particles are given an electric charge as they pass
through a charged screen; then they are
attracted to one of two electrically charged
plates through which they pass; from time to
time they are removed from the plates.

electro-zinc plated See galvanized.

electrum A natural alloy of gold and silver,
sometimes employed in the decorations of
ancient temples and palaces.

element See building element.

elementary school, grade school An edu-
cational institution which offers instruction usu-
ally from the first year through the sixth or
eighth year of schooling.

elemi A fragrant yellow-brown resin obtained
from tropical trees; used in varnishes and lacquers.

elephant trunk A long cylindrical tube with a
hopper-like top; used as a chute for concrete in
placing the concrete in deep shafts or forms; the
tube is kept filled with concrete, so that there is
no free fall of material and resultant segregation
of its constituents is avoided.

elevated floor See raised floor.

elevated water tank A gravity water tank.

elevated-water-tank system See gravity
water system. A water supply system for a build-
ing in which water is pumped from the water
main to an elevated water storage tank located
above the highest and most hydraulically remote
point in the water supply system; the height of
the tank increases the pressure in the water dis-
tribution system.

elevation l.A drawing showing the vertical
elements of a building, either exterior or interior,
as a direct projection to a vertical plane. 2. The
vertical distance above or below some estab-
lished reference level.

elevator A hoisting and lowering mechanism
equipped with a car or platform which moves in
guides in a vertical direction, and which serves
two or more floors of a building or structure; also
see dumbwaiter. Also see freight elevator, hand
elevator, hydraulic elevator, passenger elevator,
power elevator, sidewalk elevator.

elevator buffer See buffer, 2.

elevator bumper See bumper, 1.

362

Elizabethan architecture

SIDE ELEVATION

elevation, 1

elevator car The load-carrying unit of an ele-
vator, including its platform, car frame, enclo-
sure, and door or gate.

elevator car annunciator An electrical de-
vice that indicates the elevator landings where
call buttons have been pressed.

elevator car door A door at the entrance to
an elevator car.

elevator car-frame sling The supporting
frame of an elevator to which are attached the car
platform, guide shoes, elevator car safety, hoisting
ropes (or sheaves), and/or associated equipment.

elevator car-leveling device Any mechanism
or control that, when activated, will move the car
to a landing and stop the car at such landing.

elevator car platform The structure which
forms the floor of an elevator car and directly
supports the load.

elevator car safety, counterweight safety
A mechanical device attached to an elevator car
frame or to the frame of the counterweight;
slows down, stops, and holds the car or counter-
weight in the event of excessive speed or free fall
of the car, or if the wire ropes slacken, break, or
pull out of their fastenings.

elevator counterweight A counterweight
carried by an elevator cable to balance the
weight of an elevator cab; the counterweight
travels upward when the cab travels downward,
and vice versa; usually composed of steel plates
stacked within a frame.

elevator hoistway See hoistway.

elevator interlock A device on each door at an
elevator landing; prevents movement of an eleva-
tor unless the door is locked in the closed position.

elevator landing That portion of a floor, bal-
cony, or platform adjacent to an elevator hoist-
way which is used to receive and discharge
passengers or freight.

elevator machine beam, elevator sheave
beam A steel beam, within an elevator
machinery room, which is beneath and supports
elevator equipment; usually directly over the
elevator hoistway (shaft).

elevator pit That portion of an elevator shaft or
hoistway extending below the level of the bottom
landing saddle to provide for bottom overtravel
and clearance, and for elevator parts that require
space below the bottom limit of car travel.

elevator shaft An elevator hoistway.

elevator sheave beam See elevator machine
beam.

elevator stage, drop stage, lift stage A the-
ater stage floor which moves vertically on an
elevator, usually so that one set can quickly
replace another; may consist of a single unit or
articulated sections.

elevator vestibule An elevator car enclosed
by noncombustible smoke-barrier partitions that
conform to applicable code requirements.

Elizabethan architecture The transitional
style between Gothic and Renaissance in

Elizabethan architecture

363

Elizabethan Manor style

England, named after Elizabeth I (1558-1603);
mainly country houses, characterized by large mul-
lioned windows and strapwork ornamentation.

Elizabethan Manor style See Tudor Revival.

ell, el l.A secondary wing or extension of a
building at right angles to its principal dimen-
sion. 2. Same as elbow.

elliptical arch An arch having the shape of
half an ellipse; in its construction, the ellipse
is often approximated by three adjoining cir-
cular arcs.

elliptical arch

elliptical fanlight A fanlight that has the
shape of half an ellipse, often placed over a door;
rods or bars radiating from a point are suggestive
of the shape of an open fan. Also called a semi-
elliptical fanlight.

elliptical stair A stair which winds about a
solid elliptic newel or elliptically shaped well, 1.

elm A tough, strong, moderately high-density
hardwood of brown color; often has twisted,
interlocked grain. Common in cultivation for
shade and ornament; used for decorative veneer,
piles, and planks.

elongated piece A particle of aggregate hav-
ing the ratio of its length to width greater than a
specified value.

elongation See strain.

eluriation The conditioning of sludge from
sanitary waste so that certain constituents are
removed by successive decontaminations using
fresh water or plant effuents, thereby reducing
requirements for conditioning chemicals.

EM Abbr. for "end matched."

emarginated Having the margin broken by a
notch or notches.

embankment A bank of earth, gravel, or
other material constructed above the natural
ground surface; often used to carry a road, or as a
dam to hold back water.

embarrado In Spanish Colonial architecture

and derivatives, said of a surface that is roughly
plastered with adobe or mud.

embattled, embattlemented Having battle-
ments.

embattled molding A crenelated molding.

embattlement Same as battlement.

embedded column A column that is partly
built within the face of a wall.

embedded reinforcement See reinforce-
ment, 1 .

embedding compound Same as taping com-
pound.

embedment A steel component which is cast
in concrete and used to transmit externally
applied loads to the concrete structure.

embedment drawings Drawings showing the
location and placement of those components
that are installed to receive structural steel.

embedment length The length of embedded
steel reinforcement, 1 provided beyond a critical
section.

embellishment Ornamentation; adornment
with decorative elements.

emblemata, emblema A type of inlaid work
used by the early Romans to embellish floors,
panels, and the like.

emblemata

emboss To raise or indent a pattern on the sur-
face of a material; sometimes produced by the
use of patterned rollers.

embow To form in a vault or arch.

embowed Having an outward-curving projec-
tion, as a bay window.

embrasure l.The crenels or intervals between
the merlons of a battlement. 2. An enlargement

364

emulsion

embrasure:

of a door or window opening, at the inside face of
the wall, by means of splayed sides.

EMC See electric metallic conduit.

emergency-exit lighting A system designed
and maintained to assure necessary exit illumi-
nation in the event of failure of the normal
lighting in the building.

emergency-exit window See fire-escape
window.

emergency lighting Lighting designed to
supply illumination which is essential to safety
in the event of failure of the normal electric
power supply.

emergency power generator See standby
power generator.

emergency release On a door, a safety device
other than a panic exit device which permits
egress under emergency conditions.

emery A granular form of impure carborundum;
used for grinding and polishing glass, stone, and
metal surfaces.

emery cloth A cloth which is coated with
powdered emery; used wet or dry (usually on
metal) in a manner similar to that of sandpaper,
esp. for fine smoothing or polishing.

emf Abbr. for electromotive force.

eminent domain The power of the state to
appropriate private property, usually for public
use and with the payment of compensation to
the owner.

eminently hydraulic lime A hydraulic lime
that sets exceedingly fast, usually in less than
one week.

emission The radiation of energy (for example,

electromagnetic, heat, light, or sound).
emissivity See thermal emissivity.

emittance The ratio of radiant flux emitted by
a material to that emitted by a blackbody at the
same temperature, under the same conditions.

Empire style The elaborate neoclassic style of
the French First Empire (1804-1815).

emplecton A type of masonry commonly used
by the Romans and Greeks, esp. in fortification
walls, in which the exterior faces of the wall
were built of ashlar in alternate headers and
stretchers, and with the intervening space filled
with rubble.

emplecton

employer's liability insurance Insurance
protection for the employer against claims by
employees for damages which arise out of
injuries or diseases sustained in the course of
their work and which are based on common law
negligence rather than on liability under work-
men's compensation acts.

emporium In ancient Roman towns, a large
building in which foreign merchandise, imported
by sea, was deposited until disposed of to retail
dealers.

empty-cell process A method of impregnat-
ing wood with fluid preservatives under pressure.

EMT Abbr. for electrical metallic tubing.

emulsified asphalt An emulsion of asphalt
cement and water containing small amounts of
an emulsifying agent.

emulsifier A substance which modifies the sur-
face tension of colloidal droplets, keeping them
from coalescing and keeping them suspended.

emulsion l.A mixture of liquids insoluble in
one another, in which one is suspended in the
other in the form of minute globules. 2. A mix-
ture in which solid particles are suspended in a

365

emulsion glue

liquid in which they are insoluble, as a mixture
of bitumen and water, with uniform dispersion of
the bitumen globules. The cementing action
needed in roofing and waterproofing takes place
as the water evaporates.

emulsion glue A glue, usually cold-setting,
made from emulsified synthetic polymers.

emulsion paint A paint composed of small
beads of resin binder which are dispersed, along
with pigments, in water. On evaporation of the
water, the resin particles coalesce to form a film
which adheres to the surface and binds the pig-
ment particles.

emulsion sealant See latex sealant.

EN AM On drawings, abbr. for enamel.

enamel A paint made of finely ground pig-
ments and a resin binder that dries to form a
hard, smooth, glassy film having very little sur-
face texture.

enameled brick See glazed brick.

encarpus A sculptured festoon of fruit and
flowers.

encarpus

encased Said of a steel-framed structure in
which all of the individual framing members are
completely enclosed in cast-in-place concrete.

encased beam A metal beam enclosed in
another material, usually concrete.

encased electrode An electrode encased in
concrete (located within and near the bottom of
a concrete footing or foundation); the electrode,
which may consist of reinforcing bars or rods,
must be in electrical contact with the earth.

encased knot A knot that is not intergrown
with the surrounding wood; a dead knot.

encasement 1. A rigid structure or pipe which
surrounds a buried pipe, providing it with added
support or protection. 2. See pile encasement.

encastre Embedded.

encaustic 1. Painted with a mixture of a paint
solution and wax which, after application, is set
by heat. 2. Colors which have been applied to
brick, glass, porcelain, and tile and set by the
application of heat.

encaustic tile A tile for pavement and wall
decoration, in which the pattern is inlaid or
incrusted in clay of one color in a ground of clay
of another color.

part of a Medieval pavement of encaustic tiles

enceinte An enclosing wall; usually the princi-
pal perimeter of a medieval fort.

enchased Descriptive of a variety of hammered
metalwork in which a pattern in relief is pro-
duced by hammering down the background or
depressed portions of the design.

enclosed fuse A cartridge fuse.

enclosed knot An unexposed knot completely
covered by surrounding wood so that it does not
appear on the surface.

enclosed platform The partially enclosed,
raised portion of an assembly room, the ceiling
of which is not more than a specified distance
above the top of the proscenium opening;
designed or used for the presentation of plays or
other entertainment wherein scenery, drops,
decorations, etc., may be used.

enclosed shaft Same as covered shaft.

enclosed stair Same as box stair.

366

end lap

enclosure wall l.Any non- load-bearing wall
in skeleton construction; usually anchored to
piers, columns, or floors; a curtain wall. 2. The
curved metal or glass partition surrounding a
revolving door.

encorbelment The projection of each course, 1
of masonry over the course below it.

encroachment The unauthorized extension of
a building, or part thereof, on the land of another.

encumbrance A restriction on the use of real
property, or an obligation to make a payment
which is secured by real property and which does
not prevent its conveyance.

end anchorage A mechanical device used to
transmit prestressing force to the reinforced con-
crete in a posttensioned member.

endbeam See beam.

end-bearing pile A pile principally supported
at its toe (point), which rests on or is embedded
in a bearing stratum.

end-bearing sleeve A device which fits over
the abutting ends of two steel reinforcing bars;
used to assure transfer of axial compression only
from one bar to the other.

end-bedded Same as face-bedded.

end block 1 . An enlarged end section of a
member, designed to reduce anchorage stresses
to allowable values. 2. Same as anchor block.

endboard A wood board that closes off the end
of a cornice where there is no cornice return.

endboard at cornice

end butt joint Same as end joint.

end channel A horizontal stiffener which is
welded into the top and bottom of hollow-metal
doors to provide strength and rigidity.

end checks Checks that develop in the end
grain of lumber during drying.

end chimney A chimney located at an end
gable of a house; may be either an interior chim-
ney in which the outer surface is flush with an
exterior wall, or an exterior chimney in which the
chimney projects from the exterior of the end wall.

end-construction tile Tile designed to re-
ceive its principal stress parallel to the axes of
the cells; laid with axes of the cells in the verti-
cal direction.

end dam A flashing that is placed so that water
cannot run out at one end.

en delit Descriptive of a Gothic stone shaft
whose grain is vertical instead of horizontal.

end distance The distance between the end of
a timber which is bolted and the center of the
nearest bolt hole.

end gable A gable at the end wall of a house.

end girt A heavy timber that acts as a main hor-
izontal support for the second floor in an early
timber-framed house; it is located along one end
of the house, for example, between a center post
and each of the corner posts; serves to tie together
various components of the timber framing. Also
see illustration under timber-framed house.

end grain The wood grain that is exposed when
a cut is made at right angles to the grain.

end-grain core Plywood or panel core com-
posed of wood blocks sawn and glued so that the
grain is at right angles to the faces of the panels.

end-grain nailing Nailing into an end-grain
surface of wood so that the shank of each nail is
parallel to the grain.

end house A house having one of its two ends
facing the street.

end joint l.A joint formed when boards are
joined end to end, as a butt joint. 2. A joint,
perpendicular to the grain, formed between two
veneers. 3. A joint formed by the butt ends of
two bricks which are connected with mortar.

end joint, 1 with fishplates

end lap The amount of overlap in a lap joint, as
at the end of a ply of roofing felt.

367

end lap joint

end lap joint An angle joint formed by two
members, each of which has been cut to half its
thickness and lapped over the other.

end lap joint

endless saw Same as band saw.

end»matched Said of boards or strips having a
tongue along one end and a groove along the other.

endothermic Said of a reaction which occurs
with the absorption of heat.

end post A post or a structural member which
is in compression at the end of a truss.

end scarf A scarf joint between two timbers
formed by the insertion of one end into the
other, similar to a mortise and tenon joint.

end scroll Same as volute.

end stiffener One of the vertical angles con-
nected to the web of a beam or girder at its ends;
used to stiffen the web and transfer the end shear
to the shoe, baseplate, or supporting member.

end thrust The force exerted by the end of a

structural member.

endurance limit In fatigue testing, the maxi-
mum stress which can be applied to a material
for an infinite number of stress cycles without
resulting in failure of the material.

energized Connected to a source of voltage.

energy The capacity to do work; the amount of
work that a system is capable of doing.

energy cutoff device A safety device used in
a water heater to interrupt the flow of energy to
the heater if the temperature or pressure exceeds
a preset value anywhere within the water heat-
ing system; required by most codes to protect the
water heater and to prevent possible associated
equipment damage and/or loss of life.

enfilade The alignment of a series of doors axi-
ally through a sequence of rooms.

enframement Same as surround, 1.

engaged Attached (or apparently attached) to
a wall by being partly embedded or bonded to it;
for example, an engaged column.

engaged bollard A low post, partially incor-
porated in a wall or column surface; set to pre-
vent motor vehicles from damaging the surface.

engaged column, attached column A col-
umn partially built into a wall, not freestanding.

engaged columns

engaged order A series of engaged columns.

engaged pier A pier, 1 that is partially built

into a wall.
engaged porch Same as integral porch.

engineer A person trained and experienced in the
profession of engineering; a person licensed to
practice the profession by the authority in the area.

engineer-architect See architect-engineer.

engineered brick Brick having the nominal
dimensions 3 l A in. by 4 in. by 8 in. (8.13 cm by
10.16 cm by 20.36 cm).

engineered fill Soil or crushed stone that is
compacted and used as fill, 1 .

engineering brick (Brit. ) Brick having a dense,
strong, semivitreous body conforming to these
limits: Class A: compressive strength 69.0 x 10 6 N
per sq m; maximum water absorption 4-5%. Class
B: compressive strength 48.5 X 10 6 N per sq m;
maximum water absorption 7%.

engineering geology The application of
geology and its principles in the investigation
and evaluation of naturally occurring rock and
soil for use in the design of civil works.

368

English garden wall bond

engineering officer A person designated,
usually by a military component or a corpo-
ration, as having authoritative charge over cer-
tain specific engineering operations and duties.

engineering services See building services.

engineering survey A survey conducted to
obtain essential information for planning an
engineering project or developing and estimat-
ing its cost.

engineer-in-training A designation pre-
scribed by statute for a person qualified for pro-
fessional engineering registration in all respects
except the required professional experience.

engineer's chain A distance measuring device
used in land surveying consisting of a series of
links; in the US, each link is 1 ft long; the length
of the chain is 100 ft.

engineer's level Any of a group of precision
leveling instruments for establishing a horizon-
tal line of sight; used to determine differences of
elevation.

engineer's scale A straightedge, divided uni-
formly into multiples of 10 divisions per inch so
that drawings may be made with decimal values
of distances, loads, forces, etc.

engineer's scale

English barn 1. A timber-framed barn built of
wood or stone, usually connected to the house
through a series of outbuildings. 2. Same as Yan-
kee barn.

English basement In the United States, the
lowest floor of a residential building that is
partly below, but mostly above, grade; the prin-
cipal entrance to the building is at the level of
the floor above.

English bond A brickwork pattern in which
courses of headers and courses of stretchers

■ ' ■ M . fl-.JL-L.

■Jl*

^SH

tSF

1 H B B |"_fl_ _|f^ a

—j—

L Jl I "~1T

^r~CT7Ti i ji if

alternate; forms a strong bond and is easy to

lay.
English cottage A term occasionally used as a

synonym for cottage orne.
English cross bond, Saint Andrew's cross

bond Similar to English bond, but the

stretchers, in alternating courses, have their

joints displaced by half the length of a

stretcher.

1 1 W/M W/M

II 1 M II 1 1 ll 1

1 Y//////A W/////A

III 1 1 1 1 1 1 1 1 1

1 W/M W////A 1

II 1 1 1 M III 1 1

W/M V//////A \

II 1 1 1 1 1 1 1 1 1 !

English cross bond

English frame house In colonial America,
particularly along the mid- Atlantic coast in the
middle and latter part of the 17th century, a
timber-framed house whose construction fol-
lowed the then-current traditional framing tech-
niques used in England of massive timbers with
very strong joints.

English gambrel roof A gambrel roof in

which the upper and lower slopes are of
approximately equal length, but the lower
slope is of much steeper pitch, usually about 60
degrees.

English garden An informal garden whose
plantings, walks, and pools do not form any rec-
ognizable plan and are deliberately lacking in
symmetry. As a supposed imitation of natural
scenery, paths tend to be sinuous rather than
straight, and trees and bushes are casually
arranged; the antithesis of a formal garden.

English garden wall bond Like common
bond except that headers occur every fourth

English bond

English garden wall bond

369

English half-timbered style

English half-timbered style See Neo-Tudor.

English log house A one-room log cabin,
square in plan, having an exterior gable-end
chimney; one exterior door is centered on the
facade of the house and another door is centered
on the rear wall.

English one-bay house In the 17th century,
a house in America which had a one-room plan;
widely used by English immigrants.

English Regency See Regency Revival and
Regency style.

English Revival, English Tudor style See
Tudor Revival and Neo-Tudor.

English tile A single-lap, flat, smooth roofing
tile having interlocking sides.

ENGR On drawings, abbr. for "engineer."

engrailed Scalloped with concave lines; cut
along the edge with a series of small concave
curves, usually of the same size.

engraved glass Glass whose surface has deco-
rative designs, often produced by abrading its
surface with a diamond point, copper wheel, or
carborundum pencil.

ENGRG On drawings, abbr. for "engineering."

enlucido In Spanish architecture and its deriv-
atives, a term descriptive of a surface that is plas-
tered.

enneastyle A term descriptive of a portico
having nine columns in the front.

enplecton Greek or Roman masonry consist-
ing of cut stone facings with an infilling of
rubble.

enriched Having embellishment. Also see entail.

enrockment Same as riprap.

ENT See electrical nonmetallic tubing.

entablature l.In Classical architecture and
its derivatives, an elaborate horizontal band
and molding supported by columns; horizon-
tally divided into three basic elements: archi-
trave (the lowest member), frieze (the middle
member), and cornice (the uppermost mem-
ber). The proportions and detailing of an
entablature are different for each order, and
are strictly prescribed. 2. Any similar con-
struction that crowns a wall, window, or
doorway.

enriched: Corinthi;

entablature (Ionic)

entablement l.The platform which is above
the dado in a pedestal. 2. An entablature.

entail 1. Engraved or carved work. 2. Intaglio;
inlay.

entasis The intentional slight convex curving
of the vertical profile of a tapered column; used
to overcome the optical illusion of concavity
that characterizes straightsided columns.

370

epaule

entasis: proportions are much exaggerated

enterclose A passageway between two rooms
or spaces in a building.

entrained air Microscopic air bubbles inten-
tionally incorporated in mortar or concrete dur-
ing mixing, typically 10 to 1,000 JI in diameter
and nearly spherical.

entrainment See secondary air motion.

entrance The point of entry into a building: an
exterior door, a vestibule, or a lobby.

entrance cap Same as service head.

entrance hall A large vestibule or hall at the
main entryway to a Georgian style home; usually
high-ceilinged and well-lighted; commonly sub-
divided by an elliptical arch into two rooms: a
reception hall, and a stair hall that contains an
elaborate open-string staircase.

entrapped air, accidental air Voids in con-
crete, usually 1 mm or more in diameter, result-
ing from air not purposely entrained.

entrelacs See interlace.

entresol See mezzanine, 1.

entry An entrance, small hall, or vestibule
inside an exterior door.

entryway An entrance passage. Also see entry.

envelope 1 . The imaginary shape of a building
indicating its maximum volume; used to check
the plan and setback (and similar restrictions)
with respect to zoning regulations. 2. The folded-
over, continuous edge formed by turning the low-
est ply of a built-up roofing membrane over the
top surface layer; prevents bitumen from dripping

through the exposed edge joints and seepage of
water into the insulation.

envenomation The process by which deterio-
ration occurs in the surface of a plastic close to or
in contact with another surface; softening, dis-
coloration, mottling, crazing, or similar effects
may result

environment See built environment and nat-
ural environment.

environmental assessment A review of the
probable environmental consequences of a pro-
posed action, often performed to determine
whether an environmental impact statement is
required.

environmental design professions The
professions collectively responsible for the design
of man's physical environment, including archi-
tecture, engineering, landscape architecture,
urban planning, and similar environment-related
professions.

environmental impact statement A de-
tailed analysis of the probable environmental con-
sequences of proposed federal legislation, major
federal actions, or large-scale construction mak-
ing use of federal funds, likely to have significant
effects on environmental quality; such a state-
ment is required by the National Environmental
Policy Act of 1969 (42 U.S.C. §4321 et seq.).

environmental load A load, 1 on a structure
usually caused by natural forces such as wind,
rain, snow, earthquakes, or extreme tempera-
tures.

Environmental Protection Agency (EPA)
A governmental agency whose mission is to pro-
tect the natural environment by enacting and
enforcing regulations concerning conditions
that could otherwise adversely affect public
health, such as the release of pollutants.

environmentally friendly Said of a process
or product that is not destructive to the environ-
ment.

environmentally sensitive area A place
that is vulnerable to a negative environmental
impact, such as a flood plain, a wetland, an area
where noise levels are excessively high, or an
EPA-designated plant, fish, and animal habitat.

ephebeion A type of Greek gymnasium.

epaule In a medieval fortification, a corner of a
bastion where the face, 1 and flank meet.

371

epi

epi The spire-shaped termination of a projecting
point or angle of a roof.

epi

epicranitis, epikranitis l.A molding mark-
ing the top of a wall or forming the top member
of a cornice. 2. An interior cornice.

epicranitis

epinaos See opisthodomos.
episcenium Same as episkenion.
episkenion, episcenium distegia The

upper story of the scene building in an ancient

Greek or Roman theater.
epistle side In a church, the right side of an

altar as one faces the altar.
epistomium In ancient Rome, a cock or faucet

of a water pipe.
epistyle, epistylium An architrave.
epithedes The upper member of the cornice of

an entablature.

epiurus In ancient Roman construction, a
wood peg used as a nail.

epoxy A class of synthetic, thermosetting resins
which produce tough, hard, chemical-resistant
coatings and excellent adhesives.

epoxy joint In masonry, a visible joint filled
with epoxy resin in place of mortar or caulk-
ing.

epoxy mortar A mixture of a fine aggregate,
epoxy resin, and a catalyst.

epoxy paint A paint in which thermosetting
resins are contained in a vehicle that results in a
tough, very hard, chemically resistant coating;
its components must be mixed immediately
prior to use.

epoxy resin A high-strength low-shrinkage
polymer, especially designed for use in construc-
tion as an adhesive, a coating, or a foam.

epoxy weld In cut-stone fabrication, a joint at
an inside angle, cemented by an epoxy resin, to
form an apparent single unit between two pieces
of stone.

epure A full-scale, detailed drawing.

EQ On drawings, abbr. for "equal."

equalized settlement The design of a founda-
tion on the basis of equal settlement under a
dead load, rather than uniform bearing pressure
under a total load.

equalizing bed Material (such as crushed
rock) laid beneath a pipeline in a trench to pro-
vide a uniform support for the pipeline.

equilateral arch, equilateral pointed arch,
three-pointed arch A two-centered arch

in which the chords of the curves just equal the
span of the arch.

equilateral arch

372

erosion

equilateral roof A roof with sides sloping at
60°, forming an equilateral triangle in cross
section.

equilibrium The state of being equally bal-
anced; a state of a body in which the forces act-
ing on it are equally balanced.

equilibrium moisture content The mois-
ture content of a material that is stabilized at a
given humidity and temperature.

EQUIP. On drawings, abbr. for "equipment."

equipment ground l.In electric wiring, a
connection from the exposed metal parts of
equipment housings to provide a path to
ground in the event such parts become ener-
gized as a result of failure of the insulation of a
conductor housed within the equipment; a
ground connection to any noncurrent-carrying
metal parts of a wiring installation or equip-
ment, or both. 2. A ground connector to (a)
noncurrent-carrying metal parts of electrical
equipment or (b) the metallic shields of a
wiring installation, or both.

equipment regulator In gas supply services,
same as appliance regulator.

equity The value of an owner's interest in prop-
erty, computed by subtracting the amount of
outstanding mortgages or liens from the total
value of the property.

equivalent continuous sound level,
average sound level (L eq ) The sound
level, expressed in decibels, of a steady sound
which has the same A-weighted sound energy
as the time-varying sound over the averaging
period.

equivalent duct diameter The diameter of a
round duct having approximately the same area
as a rectangular duct; approximately equal to the
square root of the product of the duct width
times the duct height.

equivalent embedment length The length
of embedded reinforcement which can develop
the same stress as that which can be developed
by a hook or mechanical anchorage.

equivalent round The diameter of a circle

having a circumference equal to the outside

perimeter of other than round tube.
equivalent temperature An index similar to

effective temperature, but not considering the

effects of humidity.

equivalent thickness In a hollow masonry
unit, the thickness which the hollow masonry
unit would have if it had no voids but had the
same mass.

equivalent uniform load A conventional-
ized representation of an element of dead load or
live load; used for design purposes in lieu of the
actual load.

equiviscous temperature The temperature
at which a bitumen attains the proper viscosity
for built-up roofing application.

Erechtheum A temple on the Acropolis in
Athens; the most important monument of the
Ionic style, including a fine example of a porch
of caryatides.

Erechtheum: eastern elevation

erection The hoisting and/or installing in
place of the structural components of a build-
ing, usually using a crane, hoist, or other pow-
ered equipment.

erection bolt A bolt in the form of a threaded
rod with a head at one end, used to join struc-
tural components temporarily.

erection bracing Bracing which is installed
during erection, to hold framework in a safe con-
dition until sufficient permanent construction is
in place to provide full stability.

erection drawing One of the drawings
(together with instructions) which is provided
by a manufacturer in sufficient detail to assure
that all parts of a system can be erected prop-
erly.

erection stress Stress which is induced by
loads applied during erection of a structure.

erection tower At a construction site, a tem-
porary framework used in hoisting building com-
ponents or equipment.

ergastulum A Roman workhouse for slaves or
debtors.

erosion l.The deterioration brought about by
the abrasive action of fluids or solids in motion.
2. The gradual deterioration of a paint film due

373

erratum

to degradation of the binder, which results in
chalking, or to mechanical abrasion, such as foot
traffic.
erratum A correction of a printing, typograph-
ical, or editorial error.

errors and omissions insurance See pro-
fessional liability insurance.

ERW Abbr. for electric resistance welding.

escalator, moving staircase, moving
stairway A power-driven, inclined, contin-
uous stairway used for raising or lowering pas-
sengers.

escape The curved part of the shaft of a column
where it springs out of the base; the apophyge, 1.

escape hatch A means of escape from within
the interior of a building, usually through a
breakable or movable panel.

escape lighting Lighting provided by an inde-
pendent, self-contained source of light that acti-
vates when there is failure in the normal source
of electric power.

escape stair, fire-escape stair An interior or
exterior stair, required by law, which provides an
escape route in the event of fire.

escape route In case of emergency, a way of
travel from any point within a building to the
exterior and a place of safety. Also see fire
escape.

escarpment A steep slope in front of a fortifi-
cation to impede the approach of an enemy.

escayola A type of hard plaster or stucco.

escheat The assumption of ownership of prop-
erty by the state if no other owner can be found.

esconson Same as sconcheon.

Escorial A palace of the kings of Spain, built by
Philip II in the 16th cent, near Madrid.

escrow A legal device used in a construction
contract whereby something of value is placed
with a third party, acting as a trustee, to guar-
antee that conditions of the contract will be
met.

escutcheon l.A protective plate surrounding
the keyhole of a door, a light switch, etc.; also
called a scutcheon. 2. A flange on a pipe, used to
cover a hole in a floor through which the pipe
passes. 3. A protective or ornamental cover at
the termination of a post, picket, or rail against a
tread, floor, or wall.

key plate, escutcheon, 1

escutcheon pin A small nail, usually brass,
used for fixing an escutcheon; often ornamental.

escutcheon pin

esonarthex The second narthex from the

entrance, when two are present.
esp. Abbr. for "especially."

espadaha In Mission architecture, a decorative
gable end of a church having a multicurved mis-
sion parapet; the gable end often has a false
front, designed to be impressive; it usually does
not house a bell.

espagnolette bolt Same as cremone bolt.

espalier 1 . A trelliswork of various forms on
which the branches of fruit trees or fruit bushes
are extended horizontally, in fan shape, etc., in a
single plane, to secure a freer circulation of air
for the plant and better exposure to the sun. 2. A
tree or plant so grown.

esplanade A level open space for walking or
driving, often providing a view.

esquisse A first sketch or very rough design
drawing showing the general features of a project.

essential facility A facility in a building that
must remain functional for the public good in
the event of a major disaster, such as a severe
earthquake.

Essex board measure On a special type of
steel square used by carpenters, a chart which

374

eucalyptus

ll|M|n|ll||!III[H|ll|l||ll[|l|l|mill|ll|ll|!ll[l|!l[!l|M[H[M'nill!ll[ll[M|ll[

-H-

-&-

HH-

i:t

fiJ 1 -— s-

5 6, 7 81 91 10 II

l.l.l,l,l,l,Li.l.l,l,l,.,l,l.l„.l,l,l,l.l.l,l.1,l.l,l,l,l,,.Ll.l.l,l,l,l,l,l.l,l,l.l,l,l,l.lll.l,lll,lll,lll.l,l

Essex board measure

lists the number of board feet in a board 1 in.

thick and of various standard sizes.
EST On drawings, abbr. for estimate,
estate 1. The property of a deceased at the time

of death. 2. A property interest, usually applied

to land.
estimate

tion cost

l.See detailed estimate of construc-

2. See statement of probable construc-

3. See contractor's estimate.
estimated design load In a heating or air-
conditioning system, the sum of the useful heat
transfer, plus heat transfer from or to the con-
nected piping, plus heat transfer occurring in
any auxiliary apparatus connected to the sys-
tem.

estimated maximum load In a heating or
air-conditioning system, the calculated maxi-
mum heat transfer that the system may be called
upon to provide.

estimator A person who, by experience and
training, is capable of estimating the probable
cost of a building or portion thereof.

estipite In Spanish and Latin-American Man-
nerist architecture and derivatives, a shaft of
square cross section, tapering downward, fre-
quently combined with other unusual elements,
the whole used like an order.

estlar Old English term for ashlar.

estrade A platform or dais.

etch 1 . To cut away the surface of glass or metal
with a strong acid or by abrasive action, usually
in a decorative pattern. 2. To remove the surface
of cast stone with acid to expose the aggregate.
3. To alter the surface texture of porcelain
enamel by chemical attack.

ethylene glycol A type of alcohol, completely
miscible in water, used in latex and water-based
paints to provide stability when frozen; used in
heating and cooling systems as a fluid for trans-
ferring heat.

ETL Abbr. for "Electrical Testing Laboratories,
Inc."

Etruscan architecture The architecture of
the Etruscan people in western central Italy
from the 8th century B.C. until their conquest
by the Romans in 281 B.C. Apart from some
underground tombs and city walls, it is largely
lost, but remains important for the influence of
its construction methods on Roman architec-
ture, e.g., the stone arch.

Etruscan architecture: Arch of Augustus, Perugia

ettringite A mineral, high in sulfate calcium
sulfoaluminate; occurs naturally or is formed by
sulfate attack on mortar and concrete; desig-
nated as a cement bacillus in older literature.

eucalyptus Wood of the eucalyptus tree, native
to Australia and Tasmania, but many species now
are grown elsewhere in the world; the physical

375

eucharistic window

characteristics and properties vary considerably
with the species. Also see gumwood.

eucharistic window Same as squint, 1.

euripus 1. In ancient Rome, any artificial pond
or canal used to ornament a villa. 2. A ditch
around the arena of an amphitheater of a circus
to prevent wild animals from escaping.

eurythmy Harmony, orderliness, and elegance
of proportions.

eustyle See intercolumniation.

euthynteria The top course of the foundation
of a Classical Greek temple; used to eliminate
irregularities in the foundation.

EV1S Abbr. for "edge vee one side."

evaporable water Water in set cement paste
which is present in capillaries or held by surface
forces; measured as that water which is remov-
able by drying under specified conditions.

evaporation Loss of vaporized water, solvent,
etc., as from a paint film.

evaporation retarder An organic liquid
which, when spread on the water film on a con-
crete surface, retards the evaporation of water
resulting from bleeding, 5.

evaporative cooling Cooling accomplished
by evaporating water (usually as a fine spray)
in air; as a result, the dry-bulb temperature
decreases and the humidity increases; this prin-
ciple is used in cooling towers and in the cooling
of buildings in hot, arid climates.

evaporative cooling tower See cooling tower.

evaporative equilibrium, true wet-bulb
temperature The condition attained when
the wetted wick of a wet-bulb thermometer has
reached a stable and constant temperature when
exposed to moving air in excess of 900 ft (274-3
m) per minute.

evaporator That part of a refrigeration system
in which cooling is produced by evaporation of
the liquid refrigerant, thereby absorbing heat
and resulting in cooling.

evase Opened out, flared.

event In a CPM arrow diagram, the starting
point for an activity; occurs only when all work
preceding it has been performed.

even»textured Descriptive of wood of uniform
texture with little difference in cell size between
springwood and summerwood.

evergreen Said of a plant or tree that retains its
verdure through all the seasons, as the pine and
other coniferous trees, the holly, rhododendron,
etc.

eviction Removal of a tenant from property.
Eviction may be lawful, pursuant to authoriza-
tion contained in the lease; it may be warranted
by breaches on the part of the tenant, such as
nonpayment of rent, or by other factors such as
expiration of the lease by its own terms. Unlaw-
ful eviction normally will give the tenant a right
to damages and in appropriate cases a right to be
restored to possession of the property. Also see
constructive eviction.

exastyle Same as hexastyle.

EXC On drawings, abbr. for "excavate."

excavation l.The removal of earth from its
natural position. 2. The cavity resulting from
the removal of earth.

rOUNOATIOH WALL
OUTLJNE

excavation

excavator Any of a number of power-driven
machines used to dig, move, and transport earth,
gravel, etc.

exceedance probability The probability
of a storm occurring during any one year
which equals or exceeds the rainfall rate used
in the design of the storm-water drainage
system.

excelsior, wood wool Curly, fine shavings
cut from wood.

excess condemnation Condemnation of
more property than is required for a specific pub-
lic improvement.

excess current Same as overcurrent.

excess joint A joint in brickwork in which
more mortar is applied in laying the joint than is

376

exhaust fume hood

excess joint

required for a satisfactory masonry bond. Some
of the mortar projects beyond the face of the
wall, resulting in an irregular surface and, there-
fore, relatively poor weather protection at the
mortar joint.

exchequer To use or have a pattern of checkers.

exclusionary provision In an insurance pol-
icy covering potential losses on a building, a pro-
vision that excludes certain types of losses from
the coverage provided.

excubitorium 1. A gallery in a church where
public watch was formerly kept at night on the
eve of a festival. 2. In a medieval monastery, an
apartment for night watchers whose duty it was
to call monks to their nocturnal devotions.

excubitorium, 1

exedra, exhedra l.A large niche or recess,
usually with a bench or seats, semicircular or rect-
angular in plan and either roofed or unroofed.

exedra, 1

2. In a church, a large apsidal extension of an
interior volume, normally on a main axis.

exfiltration 1 . The outward flow of air through
a wall, joints, etc. 2. In a sewer pipeline, the vol-
ume of flow leaving a pipeline into the sur-
rounding soil.

exfoliated vermiculite Vermiculite which
has been expanded, by a heat process, to many
times its original volume; suitable for light-
weight aggregate, particularly for insulating pur-
poses; used as a thermal insulation.

exfoliation Peeling, swelling, or scaling of
stone or mineral surfaces in thin layers; caused
by chemical or physical weathering or by heat.
Minerals such as vermiculite expand to many
times their original size when heat-treated.

EXH On drawings, abbr. for "exhaust."

exhaust air The air that is removed from an
air-conditioned space and discharged to the out-
doors.

exhaust-air grease extractor See grease
extractor.

exhaust fan A fan which withdraws air from a
localized area or from a space in a building from
which it is desired not to return the air to the
central air-treatment system, as from a toilet.

CEILING

EXHAUST
FAN

exhaust fan

exhaust fume hood A prefabricated cabinet
which confines odoriferous, poisonous, or

377

exhaust grille

corrosive fumes for exhausting or filtered recir-
culation; esp. used in laboratories.

exhaust grille A grille through which air is
exhausted from a conditioned space to the atmo-
sphere.

exhaust-heat recovery system See waste-
heat recovery system.

exhaust hood A protective hood over an area

(such as a kitchen stove) from which fumes and

heated air may be removed by an exhaust fan set

within the hood.
exhaust opening An exhaust grille or any

type of opening through which air is exhausted

from a space.
exhaust shaft An outlet duct from an exhaust

fan through which foul air or gases are expelled

to the atmosphere.

exhaust ventilation The removal of foul air
from a space by a mechanical means, such as a
fan; fresh air is allowed to enter through avail-
able or controlled openings.

EXIST. On drawings, abbr. for "existing."

existing building In regulations and in codes,
a building which is already completed or which
may be built under prior laws or regulations.

existing grade The grade, 2 prior to excava-
tion or filling.

existing work In regulations and in codes,
such as a utility service or a system (or any part
thereof) installed prior to the effective date of
the applicable regulations or code.

exit That portion of a means of egress which is
separated from the rest of a building by walls,
floors, doors, or other means and which provides
a reasonably protected path of escape for the
occupants of a building in the event of fire.

exit access That portion of a means of egress
which leads to an exit.

exit corridor A corridor or enclosed passage-
way connecting a stairway, fire tower, or other
required exit with a street or alley or with an
open space communicating with a street or alley.

exit court A yard or court providing egress to a

public way for one or more required exits.
exit device See panic exit device.

exit discharge That portion of a means of
egress between the termination of the exit at the
exterior of a building and the ground level.

exit door A door that leads to an escape route to
the exterior in case of fire; the door must carry an
exit sign that conforms with the applicable code.

exit light An illuminated sign used to identify
an exit.

exit passageway An enclosed means of egress
connecting a required exit or exit court with a
public way.

exonarthex The narthex nearest the entrance,
when two are present.

exostes A loggia having a balcony.

exothermic Said of a reaction that occurs with
the evolution of heat.

exotic plant A plant that is not native to the
locality or region in which it is being grown.

Exotic Revival, Exotic Eclectic A term
descriptive of architecture based loosely on
exotic prototypes, moderately popular primarily
from about 1835 to 1890. See Egyptian Revival,
Moorish Revival, Oriental Revival, Swiss Cot-
tage architecture.

expanded blast-furnace slag, foamed
blast-furnace slag The lightweight cellular
material obtained by controlled processing of
molten blast-furnace slag with water, or with
water and other agents such as steam or com-
pressed air or both. Also see blast-furnace slag.

expanded cement See expansive cement.

expanded clay Clay which has been heated to
a semiplastic condition and expanded to many
times its original volume by the formation of
internal gas; used as a lightweight aggregate.

expanded corner bead A corner bead hav-
ing wide expanded flanges that are easily flexed;
provides increased reinforcement.

expanded corner bead

expanded glass See foam glass.

expanded metal A type of metal lath having
an open mesh formed by slitting metal sheet;
made in various patterns and metal thicknesses,
with either a flat or an irregular surface.

378

expansion bit

expanded metal

expanded-metal lath A metal lath used as a
base on which to apply plaster; usually fabricated
by slitting sheet metal and then stretching it to
form openings through which plaster is troweled;
the lath holds the plaster coat firmly in place.

expanded-metal partition A partition formed
of heavy expanded-metal lath on thin framing or
support members, both sides of which are plas-
tered to form a solid assembly, usually about 1 Vi to
2Vi in. (3.8 to 6.4 cm) thick.

expanded perlite A natural, volcanic, glassy,
light, cellular material suitable for lightweight
aggregate in concrete.

expanded plastic l.See cellular plastic. 2.
See foamed plastic, 1.

expanded polystyrene A foamed styrene
plastic; has high resistance to heat flow;
mechanical strength relatively high for such a
light material.

expanded polyurethane A type of expanded
foamed plastic that is commonly used as thermal
insulation in a cavity wall; some types of foamed
plastic can be formed at the site.

expanded rubber Cellular rubber having
closed cells, made from a solid rubber compound.

expanded shale Shale which has been heat-
treated so that it expands to many times its orig-
inal volume; used as a lightweight aggregate.

expanded slate Slate which has expanded to
many times its original volume as a result of

exfoliation; this heating process causes the for-
mation of internal gas, producing a porous struc-
ture which is retained upon cooling so the
material is suitable as a lightweight aggregate.

expanding bit Same as expansion bit.

expanded vermiculite Same as exfoliated
vermiculite.

expanding cement Same as expansive cement.

expanding pile A pile provided with a mechan-
ical device at its lower end to expand the bottom
so as to provide greater bearing and a higher resis-
tance to uplift.

expanding vault A conical vault.

expansion The increase in length or volume of
a material, or a body, caused by temperature,
moisture, or other environmental condition.

expansion anchor Same as expansion bolt.

expansion attic An unfinished attic in a com-
pleted house, capable of being converted into
livable area.

expansion bearing A support at the end of a
span where provision is made for the expansion
and contraction of the structure.

expansion bend, expansion loop A bend
(usually in the form of a horseshoe or Q.) which
is inserted in a pipe run to provide for the expan-
sion of the pipe resulting from a temperature
change.

=u9

expansion bends

expansion bit, expansive bit A bit, of

adjustable size, for cutting holes in wood. (See
illustration p . 380.)

379

expansion bolt

BLADE
t SPUR

expansion bit

expansion bolt An anchoring device hav-
ing an expandable socket that swells as a bolt
is tightened into it; used in masonry walls
for attaching timber, etc.

expansion bolts

expansion coefficient See coefficient of
expansion.

expansion coil An evaporator constructed of
pipe or tubing.

expansion-compression joint Same as
expansion joint.

expansion fastener Same as expansion bolt.

expansion fitting See expansion bend.

expansion joint l.A joint or gap between
adjacent parts of a building, structure, or con-
crete work which permits their relative move-
ment due to temperature changes (or other
conditions) without rupture or damage. 2. An
expansion bend.

J0INTF1LLER WATERSTOP

expansion joint, 1

expansion joint cover A prefabricated cover

which serves to protect an expansion joint, 1 ;
designed to accommodate relative movement
between the surfaces on the two sides of the
joint.

expansion joint filler See joint filler, 2.

expansion loop See expansion bend.

expansion shield Same as expansion bolt.

expansion sleeve A pipe sleeve which per-
mits movement of the element that it houses.

expansion strip Material in an expansion
joint.

expansion tank A tank in a hot-water heating
system, above the heating tank, which allows
for the increased volume of water when heated.

expansion valve In a refrigeration system, a
valve for controlling the flow of refrigerant to
the cooling element.

expansive bit See expansion bit.

expansive cement, sulfoaluminate cement
A cement which when mixed with water forms a
paste that tends to increase in volume, after set-
ting, to a significantly greater degree than port-
land cement paste does; used to compensate for
volume decrease due to shrinkage or to induce
tensile stress in reinforcement. Classified as Type
K: Contains anhydrous aluminosulfate burned
simultaneously with a portland cement composi-
tion, or burned separately when it is to be inter-
ground with portland cement clinker or blended
with portland cement, calcium sulfate, and free
lime. "Type M: A mixture of portland cement, cal-
cium aluminate cement, and calcium sulfate.
"Type S: A portland cement containing a large
computed tricalcium aluminate content, modi-
fied by an excess of calcium sulfate above usual
optimum content.

expansive-cement concrete Concrete made
with expansive cement in order to reduce or con-
trol volume changes during the curing period.
Also see self-stressing, shrinkage-compensating.

380

extended-care facility

expansive hydraulic cement A hydraulic
cement that forms a paste when mixed with
water, thereby increasing in volume by a con-
trolled amount during the early hardening
period which occurs after setting.

expansive soil Soil that tends to increase in
volume as a result of an increase in its water
content.

EXP BT On drawings, abbr. for expansion bolt.

expert witness A witness in a court case or
other legal proceeding, or in an arbitration pro-
ceeding, who, by virtue of his experience, train-
ing, skill, and knowledge of a particular field or
subject, is recognized as being especially quali-
fied to render an informed opinion on matters
relating to that field or subject.

expiatory chapel A chapel erected to expiate
a murder or other great crime.

expletive Something used to fill up, as a piece
of masonry used to fill a cavity.

exploded view A drawing, rendering, or the
like showing the individual disassembled com-
ponents of an apparatus, device, or machine; the
parts are shown in their proper relationship with
respect to their assembled position.

exploration The general activity undertaken
to identify and classify the elements of which a
soil mass is constituted.

explosion-proof Said of an enclosure that is
capable of withstanding an explosion of a speci-
fied gas or vapor that may occur within it, and of
preventing the ignition of the gas or vapor sur-
rounding it.

explosive Any explosive chemical compound,
mixture, or device, the primary or common pur-
pose of which is to produce an explosion; i.e.,
with substantially instantaneous release of gas
and heat, unless such compound, mixture, or
device is otherwise specifically classified by the
US Department of Transportation. Class A: pos-
sessing detonating hazard, such as dynamite or
nitroglycerin. Class B: possessing flammable haz-
ard, such as propellant explosives. Class C: con-
taining class A or class B explosives, but in
restricted quantities.

explosive actuated gun See stud gun.

explosive rivet A rivet having an explosive-
filled, hollow shank; the rivet is inserted, then the
shank is exploded by striking it with a hammer.

exposed l.Said of an electrically live part
which can be touched or approached nearer
than a safe distance by a person; not suitably
guarded, isolated, or insulated. 2. Said of a sys-
tem (such as gas piping or electrical wiring)
which is visible in the finished structure.

exposed-aggregate finish A decorative fin-
ish for concrete work; achieved by removing the
outer skin of mortar, generally before the con-
crete has fully hardened, and exposing the
coarse aggregate.

exposed finish tile Tile whose surfaces are
intended to be left exposed or painted; tile may
be smooth, combed, or roughened.

exposed masonry Any masonry construction
having no surface finish other than paint applied
to the wall face.

exposed nailing See nailing.

exposed suspension system, grid system
A system for suspending an acoustical ceiling in
which the members supporting the acoustical
material are visible in the room.

exposed suspension system

exposure Of a wood shake: same as weather, 1.

exposure hazard The probability that a build-
ing will be exposed to fire in surrounding or
adjoining property.

exposure line An imaginary line drawn across
a wood shake, dividing it so that the area above
this line is the same area as that below it; the
area below the line is that portion of the shake
exposed to the weather.

expulsion fuse A fuse that uses the gases pro-
duced by an arc and the lining of the fuse holder to
extinguish the arc produced when the fuse melts.

EXT On drawings, abbr. for "exterior."

extended-care facility An institution in
which resident patients receive medical, nurs-
ing, and rehabilitative services for medical
conditions less acute than those normally
cared for in a general hospital. May be an inde-
pendent building or a designated portion of a
hospital.

381

extended coverage insurance

extended coverage insurance l.See prop-
erty insurance. 2. See steam boiler and machin-
ery insurance.

extended coverage sprinkler In a fire sprin-
kler system, a type of spray sprinkler (i.e., sprin-
kler head) which extends the usual maximum
area of protection; listed as a special sprinkler.

extended pigments An organic pigment that
has been diluted with an extender (e.g., calcium
carbonate or blanc fixe).

extended-service lamp See long-life lamp.

extended surface Additional surface on a
pipe or tube used in heat transfer, usually con-
sisting of metal fins, disks, pins, or ribs.

extender 1. A white, inert mineral pigment of
low opacity; used in paints to provide bulk, tex-
ture, or a lower gloss or to reduce paint cost.
Common extenders are calcium carbonate, sil-
ica, diatomaceous earth, talc, and clay. 2. A sub-
stance added to synthetic resin adhesives to
increase volume and reduce cost without affect-
ing quality.

extensibility The capacity of a sealant to be
stretched in tension.

extension A wing or structure added to an
existing building.

extension bolt Same as extension flush bolt.

extension casement hinge On a casement
window which has a sash (ventilator, 2) that
swings outward, an exterior hinge so located
that when the window is open clearance is pro-
vided on the hinge side to permit cleaning from
the inside.

extension casement hinge

extension device Any device (excluding an
adjustment screw) used to obtain vertical adjust-
ment.

extension flush bolt A type of flush bolt; bolt
head is connected to the operating mechanism
by a rod inserted through a hole bored in the
door.

extension flush bolt

extension ladder A ladder which has more
than one section, each sliding within the other,
so that it can be extended in length.

extension link A hardware device used to pro-
vide a long backset in the bored lock of a door.

extension rule A rule containing a calibrated
sliding insert which may be extended.

extension trestle ladder A ladder which is
self-supporting and adjustable in length; consists
of a tresde ladder base and a vertically-adjustable
single ladder which may be interlocked.

exterior balcony A landing or porch project-
ing from the wall of a building.

exterior chimney, external chimney A
chimney located outside, and usually attached
to, an exterior wall of a house at the gable end,
gambrel end, or mansard end.

exterior corner reinforcement A pre-
formed section of expanded sheet metal used to
reinforce exterior stucco or plaster corners.

exterior door A door that connects the inte-
rior of the building with the exterior.

exterior finish The outer finish of a building
which provides protection against weather or
serves as a decorative element.

exterior glazed Said of glazing that has been
set from the outside of the building.

exterior insulation and finishing system
An exterior finish for a building composed of
polystyrene foam covered with a synthetic
stucco; this type of stucco (in contrast to

382

extruded compactor

traditional, porous cement-based stucco) is
waterproof and is sprayed on.

exterior paint A paint with durable binder
and pigments especially formulated to withstand
exposure to weather.

exterior panel One of the panels of a flat con-
crete slab having at least one edge which does
not join another panel.

exterior plywood A structural glue-laminated

timber that is made of three or more plies (usually
an odd number); the glue must be waterproof.

exterior ramp A ramp, 1 that is an appendage
to a building, leading to a level above or below
existing ground level.

exterior separation The distance from the
outermost exterior wall of a building to the cen-
ter line of an adjacent street or public space, or
to an interior lot line, or to a line halfway
between the exterior wall and the wall of
another building on the same lot.

exterior stair A stair exposed to the outdoors;
often it is a legally required exit.

exterior trim Any material applied to an exte-
rior wall that, if removed or destroyed, will not
reduce the structural stability of the building
enclosure, and that is installed so as not to
reduce the required fire-resistance rating of the
enclosure. May include belt courses, cornices,
fascias, gutters, half-timber work, overhanging
eaves, shutters, surrounds, trellises, and mold-
ings around doors and windows; does not
include door and window frames and sashes.

exterior-type plywood Plywood bonded with

a fully waterproof glueline.
exterior wall, external wall, periphery

■wall A wall which is part of the envelope of a

building, thereby having one face exposed to the

weather or to earth.

external dormer See dormer window.

external leaf The leaf of a cavity wall which
faces the exterior.

external thread Same as outside thread.

external vibration Energetic agitation of
freshly mixed concrete by means of a vibrating
device which is attached at selected positions on
the concrete forms.

external wall See exterior wall.

EXTR On drawings, abbr. for "extrude."

extra Performed work or a desired item of con-
struction which is beyond the intent of the
drawings and specifications contained in a con-
struction contract; an item of work, 1 involving
additional cost. Also see addition, 3.

extractives Substances in wood such as col-
orants, oils, tannins, resin, etc., that are not an
integral part of the cell structure and can be
removed with solvents.

extrados The exterior curve or boundary of the
visible face of the arch.

Of-

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extrados: Ex

extradosed arch One which has the extrados
clearly marked, as a curve exactly or nearly paral-
lel to the intrados; has a well-marked archivolt.

extra heavy Said of a piping (usually cast iron)
that is thicker than standard.

extra-high-pressure mercury lamp A
mercury-vapor lamp that operates at a partial
pressure of about 10 atmospheres or higher.

extra-rapid-hardening cement See high-
early-strength cement.

extra services See additional services.

extra-strong pipe A standard designation for
steel or wrought-iron pipe in which the wall thick-
ness is greater than that of standard-weight pipe.

extra 'work Any work not included in the con-
tract documents; an extra.

extruded brick See wire-cut brick.

extruded compactor A type of refuse com-
pactor that produces a continuously extruded
cylinder of compacted refuse in a plastic casing, in
a manner similar to that of sausage packed into a

383

extruded corner

sausage casing. The casing is cut and sealed in
convenient lengths for ease of handling.

extruded corner A bay projecting where two
masses of an edifice form a reentrant angle, and
hence a convenient location for stairs.

extruded joint In masonry work, a seldom-
used term for excess joint.

extrusion l.The process of producing metal
shapes of a constant cross section by forcing the
hot metal through an orifice in a die by means of
a pressure ram. 2. Any item made by this process.

extrusion coating A thin film of molten resin
which has been extruded and pressed onto a sub-
strate to form a coating without an adhesive.

exudation Any liquid or liquid-like material
which oozes through a pore, crack, or opening in
a concrete surface.

eye 1. The central roundel of a pattern or orna-
ment. 2. The circular (or nearly circular) cen-
tral part of a volute, as in an Ionic capital. 3.
One of the smaller, more or less triangular,
openings between the bars of Gothic tracery. 4.
An oculus, esp. one at the summit of a dome. 5.
A hole through material for access, to permit
the passage of a pin, or to serve as a means of
attachment.

eyebar A bar with an eye at either one end or
each end; used as a tension member in a steel truss;
a pin passes through the eye, forming a joint.

eyebolt A bolt having its head in the form of a
loop or eye.

eyebolt

eyebrow, eyebrow dormer A low dormer

that has no sides, the roofing courses being car-
ried over the dormer in a continuous wavy
line.

eyebrow eave On a shingled roof, an eave
that is carried over a door entry in a continuous
wavy line.

eyebrow eave

eyebrow lintel A lintel above a window, car-
ried over the window in a continuous wavy
line.

eyebrow monitor See trapdoor monitor.

eyebrow window 1 . A bottom-hinged, inward-
opening window in the uppermost level of a
house, usually under the front eaves; often one of
a series of windows in the frieze of a Greek Revival
style building. 2. A window in an eyebrow.

eye-catcher See folly.

eye-house See I-house.

eyelet l.In a medieval castle, a small opening
for light, air, or the discharge of missiles, in a
wall or parapet; a small loophole. 2. A small hole
in a wall.

eyelid dormer
dormer.

eyelet

An especially

low eyebrow

384

F Abbr. for "Fahrenheit."

FA l.On drawings, abbr. for "fresh air" duct
section. 2. Abbr. for "fire alarm."

FAB On drawings, abbr. for "fabricate."

fabric The basic elements making up a build-
ing; the carcass without finishings or decora-
tion.

fabricated structural timbers The structural
timbers that are fabricated in a shop and moved
to the job site for installation.

fabrication A process in which a steel member
is prepared for erection; before use, it is cut to
length, punched, and drilled as required.

fabric roofing See built-up roofing.

facade The exterior face of a building which is
the architectural front, sometimes distin-
guished from the other faces by elaboration of
architectural or ornamental details.

facade gable A wall gable on the architectural
front of a building.

facade gutter See facade gutter.

facade retention The incorporation of the
exterior face of a historically significant building
in the building's reconstruction.

face 1 . The exposed surface of a wall, masonry
unit, or sheet of material. 2. The surface of a
unit designed to be exposed, as in finished
masonry, or plywood having one side which is
finished. 3. The broad surface of a board, tim-
ber, or panel. 4. The exposed vertical surface of
an arch. 5. The striking surface of a hammer. 6.
During a construction operation in a tunnel,
the surface being excavated. 7. To install a sur-
face layer of one material on another, as to face a
concrete block wall with brick.

face-bedded, edge-bedded Stone set so
that its laminae are vertical and parallel to the
exposed face.

face brick See facing brick.

face clearance The distance between the face
of a panel or light of glass and the nearest face of

its retaining frame or stop, measured normal to
the plane of the panel or glass.
faced block A concrete masonry unit having a
special ceramic, glazed, plastic, or polished, face
surface.

faced plywood Plywood faced with any sheet
material other than wood.

faced wall A wall in which the facing and
backing are so bonded as to result in a common
action under load.

face edge See work edge.

face feed In welding, the application of filler
metal to the joint, usually by hand, during braz-
ing or soldering.

face glazing Glazing set in an L-shaped or
rabbeted frame and fixed in place with a trian-
gular bead of glazing compound.

face guard A prefabricated strip, or the like,
which protects the face of a wall or column
against damage by carts, wagons, etc.

face hammer A hammer having a cutting
peen at one end and a flat striking face at the
other; used in preparing stone for finer tool
work.

face joint A joint which is visible on the face
of a masonry wall, usually more carefully
pointed or struck than the others.

face mark A pencil mark (X) which identifies
the work face of a planed timber.

face measure 1 . The measurement of the
area of a board; surface measure; superficial
measure. 2. The face width.

face mix A concrete mixture used for the
exterior face of cast stone, superior in appear-
ance and durability to the concrete cast
immediately behind, to which it is fully
bonded.

face mold 1. A template for marking the board
out of which are cut ornamental handrailings,
etc. 2. A template for checking the shape of
wood or stone surfaces.

385

face nailing

face nailing Nailing in which the nails are
driven perpendicular to the face of the mate-
rial.

face panel In a flush door constructed of
wood, a plywood panel, having a veneer finish,
which is bonded to the core and/or crossband-
ing.

faceplate Any protective plate, such as an
escutcheon or the plate over a mortised lock.

face putty, front putty The putty on the
exposed side of glass in a window frame; formed
with a putty knife in the angle of the sash after
the glass has been set in place.

FACE PUTT*

face putty

face shell The sidewall of a hollow concrete
masonry unit.

face side See work face.

face stone Stone that is used as the facing of a
building.

face string, finish string An outer string,
usually of better material or finish than the
roughstring which it covers; may be part of the
actual construction or applied to the face of the
supporting member.

facet l.One surface of a polyhedron. 2. A flat
surface between two column flutes, a fillet.

faceted glass Same as chunk glass.

face-to-face dimension In a valve or fitting,
the dimension from the face of the inlet port to
the face of the outlet port.

facette Same as facet.

face velocity The velocity of air at the face of
an air diffuser or air terminal unit.

face veneer Wood veneer selected for its deco-
rative qualities rather than its strength.

face string

face veneer

face wall 1. A retaining wall. 2. The front wall

of a building.
face weight See carpet face weight.

face width The width of the face of a piece of

dressed lumber.
facework See facing.

fachwerk The term used by German-speaking
immigrants to America in the 18th and 19th
centuries for half-timbered construction, i.e.,
the medieval system of braced timber framing
of a house in which the space between the
structural timbers is usually filled with brick or
filled with a nogging consisting of clay mixed
with chopped straw to act as a binder; then the
exterior sides of the walls were coated with
plaster (although the timbers were often left
exposed).

facia See fascia.

facility All or any portion of a building, area, or
structure, including the site on which it is
located, wherein specific services are provided or
activities are performed.

facility management Any activity related to
the maintenance and management of a building
(such as equipment operations and security)
after the building has been completed and occu-
pied.

facilities planning The long-term planning of
a building and its building services, including

386

fail-safe system

equipment operations, maintenance, possible
renovation and expansion, as well as life-cycle
planning.

facing, face-work 1 . A veneer of nonstructural
material such as stone, terra-cotta, metal, stucco,
plaster, and wood used to finish the surface of a
rougher or less attractive material. 2. Any mate-
rial, forming a part of a wall, used as a finished
surface; a revetment. 3. On thermal insulation,
the protective, functional, or decorative surface
applied at the outermost layer of insulation.

FACE PUTTV

facing

facing bond Any bond, 6 in which the face of
the wall shows mostly stretchers.

facing brick, face brick Brick esp. made or
selected to give an attractive appearance when
used without rendering or plaster or other sur-
face treatment of the wall; made of selected
clays, or treated, to produce the desired color.

facing hammer A hammer having a notched,
rectangular head; used for dressing concrete or
stone.

facing pavoir A hard burnt brick, sometimes
used as a facing brick.

facing tile A structural clay tile with exposed
faces. See ASTM standards.

factabling Same as coping.

factored load l.See design ultimate load. 2.

The product of the nominal load and a load factor.

factor of safety, safety factor 1 . The ratio

of the ultimate stress of a structure or pressure
vessel to the design working stress. 2. The
ratio of the ultimate breaking strength of a
member or piece of material or equipment to
the actual working stress or safe load when in
use.

factory, (Brit.) works A building or group of
buildings for the production or manufacture of
goods.

factory — built house Same as prefabricated
house.

factory-built chimney A chimney that is
built, tested, and listed by an organization
acceptable to the local authorities that have
jurisdiction in the area in order to ensure that it
meets acceptable standards.

factory lumber See shop lumber.

factory square An area of 10 square meters
(108 square feet).

fadding Using a pad, called a "fad," to apply
shellac.

fadeometer An apparatus for determining the
resistance of resins and other materials to fading.
It accelerates the fading by subjecting the article
to high-intensity ultraviolet rays of approxi-
mately the same wavelength as those found in
sunlight.

fading The loss of color of a paint film through
exposure to sunlight and weather.

fagon A outwardly-bulging fireplace in one cor-
ner of a room.

Fahrenheit scale A thermometric scale in
which 32° denotes freezing and 212° the boiling
point of water under normal pressure at sea
level.

FAI Abbr. for fresh-air intake.

F.A.I.A. Abbr. for "Fellow of the American
Institute of Architects."

faience, faience ware Any earthenware hav-
ing a transparent glaze; formerly, any decorated
earthenware with an opaque glaze.

faience mosaics Ceramic faience tile, less
than 6 sq in. (38.7 sq cm) in facial area, usually
about Ysin. (0.95 cm) thick.

faience tile Glazed or unglazed ceramic tile
which shows characteristic variations in the
face, edges, and glaze that give a handicrafted,
nonmechanical, decorative effect. Also see
majolica.

fail-safe system A building system designed
so that its failure (or the failure of any part of
the system) will not endanger those people
operating the system or those people in its
vicinity.

387

failure

failure In structural engineering, that condi-
tion of a structural element (or its material
components) which renders it incapable of
continuing the load-carrying function for
which it was designed; may be caused by frac-
ture or by excessive and permanent plastic
deformation.

failure by rupture See shear failure.

failure load See breaking load.

fair- faced 1 . Said of a concrete surface which
requires no further concrete treatment other
than curing, on completion of the forming
process. 2. Said of a structural timber that is
of a smoother and better quality finish than
usual.

fair-faced brickwork A neatly built, smooth
surface of brickwork.

fair raking cutting Cutting exposed brick-
work or facing at an angle to the horizontal, as
the brickwork along a gable.

fair raking cutting

fall The slope of a pipe, conduit, or channel usu-
ally expressed in inches per foot (or centimeters
per meter) or in percent.

fallback A reduction in the softening point of
bitumen used in built-up roofing; may result
from overheating.

falling door Same as flap door.

falling mold In joinery, a template used to con-
trol shaping of the surfaces of a handrailing.
falling stile Same as lock stile.

falling wainscot A movable partition that can
be positioned to separate two adjacent rooms;
hinged along its upper edge, at ceiling level, so
that the partition can be swung up to the ceiling,
thereby joining the two rooms as one.

fallout shelter A structure (or room therein)
used for protection against harmful radiation due
to radioactive fallout following a nuclear blast.

fall-pipe Same as downspout.

false arch One having the appearance of an
arch, though not of arch construction, as a cor-
bel arch.

false attic An architectural construction above
the main cornice, concealing a roof, but not
having windows or enclosing rooms.

false bearing Any bearing which is not directly
upon a vertical support.

false body An apparently high viscosity in a
paint which is considerably lowered when the
paint is brushed or stirred.

false ceiling A secondary ceiling formed to
provide space for services (such as ductwork)
above it, to change room proportions, etc; also
see suspended ceiling.

false door, blind door The representation of
a door, inserted to complete a series of doors or
to give symmetry; a blank door.

false ellipse A curve that approximates an
ellipse, but is actually made up of several adjoin-
ing circular segments.

false front 1 . A front wall which extends beyond
the sidewalls of a building to create a more impos-
ing facade. 2. A front wall that extends above the
roof of a building; a flying facade.

false half-timbering A term descriptive of a
wall construction that appears to be of half-
timbered construction, but whose woodwork is
merely decorative and serves no structural
function.

false header See clipped header.

false heartwood Wood having the appear-
ance of heartwood but not its properties.

false joint A groove routed (and generally
pointed) in a solid block of stone to simulate a
joint.

false overhang Same as hewn overhang.

false machicolation An overhanging defen-
sive structure in a medieval fortification that
has the appearance of a machicolation, but has
no opening through which rocks and boiling
liquids could be dropped on an attacker.

false pile The additional length added to the
top of a driven pile.

false plate Same as wall plate.

false proscenium A frame, on stage, directly
behind the proscenium arch; used to expose a
smaller stage area.

388

fan tracery

false roof A ceiling, esp. in an upper room or
garret, which is shaped like a roof but is sepa-
rated from the roof by a dead-air space.

false set, early stiffening, hesitation set,
plaster set, premature stiffening, rubber
set The rapid development of rigidity in a
freshly mixed portland cement paste, mortar, or
concrete without the generation of much heat;
this rigidity can be dispelled and plasticity
regained by further mixing without addition of
water.

false tenon, inserted tenon A tenon of
hardwood, inserted where the tenon of a jointed
timber has insufficient strength.

false tongue See spline.

false window, blind window The repre-
sentation of a window inserted to complete a
series of windows or to give symmetry; a blank
window.

false woodgraining Simulating a wood grain
by painting the surface with a translucent stain,
then working the stain into suitable patterns
with graining brushes, combs, and rags to pro-
vide the appearance of wood; also called faux
bois.

falsework Temporary bracing for supporting
work under construction which cannot yet sup-
port itself.

family In urban planning, one or more persons
occupying a single living unit.

fan l.An air- moving device composed of a
wheel or blade and housing or orifice plate. 2.
During construction or demolition of a building,
an upwardly projecting arrangement of scaffold-
ing and netting that is intended to catch any
debris that might otherwise fall to the ground.
Also see axial-flow fan, centrifugal fan, plenum
fan, propeller fan, return fan, supply fan,
tubeaxial fan, vaneaxial fan.

fan»coil unit In air conditioning, a unit
(which is located in the space being air condi-
tioned) containing an air filter, air heating
and/or cooling coils, and a centrifugal fan; the
unit receives a supply of fresh air either from a
central plant or from the outside by means of
an exterior wall opening at the rear of the unit.

fan convector A concealed radiator in
which a fan forces air over fins within the con-
vector; supplies more heat than a radiator of

the same physical size which lacks the fins and
fan.

fane A temple, esp. one devoted to pagan worship.

fan Fink truss A form of Fink truss having sub-
diagonals that radiate outward from a central
point.

fan Fink truss

fan groin Same as fan vault.

fanlight 1. A semicircular or semielliptical
window over the opening of a door; commonly
with radiating rods or bars suggestive of an
open fan. 2. Any window occupying a similar
position.

fanlight

fanlight catch A spring catch for locking a
hinged window, provided with a means for attach-
ing a controlling cord; esp. used on fanlights.

fan-powered terminal (FPT), fan-pow-
ered box In an air-conditioning system, a
variable air valve with an auxiliary fan to mix
induced air from a ceiling plenum with the pri-
mary air.

fan sash Same as fanlight.

fantail Any member or construction having a
form resembling the construction of a fan, esp.
applied to centering having radiating struts.

fan tracery, fanwork Tracery on the soffit of
a vault whose ribs radiate like the ribs of a fan.
(See illustration p. 390.)

389

fan truss

fan tracery

fan truss A truss which has struts supported at
their feet by a common suspension member from
which they radiate, diverging like the ribs of a fan.

fan vault A concave conical vault whose ribs,
of equal length and curvature, radiate from the
springing like the ribs of a fan.

fan window A fanlight.
fanwork See fan tracery.
FAO Abbr. for "finish all over."
FAR See floor area ratio.

farmery An infirmary in a monastery complex.

farmstead A farmhouse and its adjacent build-
ings and service areas.

fasces A symbol of Roman authority consisting
of a bundle of rods with an ax blade projecting
from them.

fascia, facia 1. Any flat horizontal member or
molding with little projection, as the bands into
which the architraves of Ionic and Corinthian
entablatures are divided. 2. Any relatively nar-
row vertical surface (but broader than a fillet)
which is projected or cantilevered or supported
on columns or element other than a wall below.
Also see platband.

fascia board Same as eaves fascia.

fascia bracket A bracket attached to an eaves
fascia that supports a gutter, 1 .

fascia gutter A gutter, 1.

fasciate Composed either of bands of molded fas-
ciae, as in the Ionic architrave, or of bands of color.

fascine A cylindrical bundle of brushwood or
the like. Such bundles are used as a foundation
mat or to protect a pier foundation from erosion.

fastener A mechanical device, weld, or rivet for
holding together two or more pieces, parts,
members, or the like.

fastigium l.The pediment of a portico, so-
called in ancient architecture because it followed
the form of the roof. 2. The crest or ridge of a roof.

fast-joint butt Same as fast-pin hinge.

fast-pin hinge A hinge in which the pin is fas-
tened permanently in place.

fan vault

fast-pin hinge

fast-response sprinkler A type of fire sprin-
kler (i.e., sprinkler head) having high thermal

390

faux bois

sensitivity, so that it responds at an early stage of
fire development.

fast sheet See fixed light.

fast- to-light Descriptive of a material, such as a
durable paint film, which does not fade when
exposed to sunlight.

fast track A method of construction man-
agement in which building construction begins
before all construction details have been finalized
in order to speed completion of the project.

fat 1. Material accumulating on a trowel during
smooth troweling; used to fill in small imperfec-
tions. 2. See fat concrete, fat lime, etc.

fat area See fat spot.

fat board A mortarboard.

fat clay A clay having a high value of liquid
limit and plasticity index.

fat concrete A concrete containing a large
proportion of mortar.

fat edge A thick paint film on the edges of
woodwork, moldings, or other painted surfaces
having sharp external angles.

fatigue The progressive structural change occur-
ring in a localized area of a metal subjected to
conditions of repeated cyclic stresses and strains
considerably below the ultimate tensile strength;
may result in cracks or complete fracture.

fatigue failure The rupture of a material as a
result of being subjected to repeated loadings at
a stress substantially less than its strength under
static conditions.

fatigue life The number of cycles of loading of
a specified character that a given specimen of
material can sustain before failure occurs; a mea-
sure of the useful life of the material.

fatigue limit The stress below which a material
can be applied cyclically for an infinite number
of times without failure.

fatigue strength A measure of the ability of a
material or structural element to carry a load
without failure when the loading is repeated a
definite number of times.

fat lime, rich lime l.pure lime (or at least
98% pure lime). 2. Lime putty having a good
spread; used to fill voids in the finish coat as it is
applied and troweled.

fat mix, rich mix A concrete or mortar
mixture containing a high ratio of binder to

aggregate, thus providing better spread and

workability.
fat mortar, rich mortar Mortar containing a

high percentage of cementitious compounds;

sticky, adheres to a trowel.
fat sand Sand containing a high proportion of

clay.
fat spot, fat area A thick place in bituminous

paving.
fattening The thickening of paint in a partially

filled can after standing for a period of time.
fatty paint Paint which has thickened because

of oxidation and polymerization of the drying-
oil vehicle during storage.
fauces In the Roman house, passageways from

the street to the atrium, or from the atrium to

the peristyle.

faucet, bibcock, water tap A water outlet
valve; also called a cock.

STEM WA&CS

faucet

faucet ear In plumbing, a projection on a bell,
2 which serves as a means of mechanical attach-
ment.

fault A defect in the insulation or conductive
capability of any component or device in an
electric circuit, resulting in an interruption of
current flow or in an unintended path of current
flow of abnormal magnitude.

fault current An electrical current that flows
from one conductor to ground (or to another
conductor) because of an abnormal connection
between the two.

faulting The differential vertical displacement
of slabs or members which are adjacent to a joint
or crack.

fausse-braye In the Middle Ages, a secondary
fortification; usually consists of a continuous
rampart and parapet placed in front of the main
rampart.

faux bois Same as false woodgraining; found,
for example, in French Vernacular architecture.

391

faux marbre

faux marbre Hand-painted wood columns that
appear to be marble.

favissa In ancient Rome, a crypt, cellar, or
underground treasury.

favus A tile or slab of marble cut into a hexago-
nal shape, so as to produce a honeycomb pattern
in pavements.

faying surface In welding, that surface of a mem-
ber which is in contact with, or in close proximity
to, another member to which it is to be joined.

fayre house 1. Early nomenclature for a tim-
ber-framed house. 2. See frame house.

fbm In the lumber industry, abbr. for "foot board
measure."

fc Abbr. for footcandle.

FD Abbr. for "floor drain."

FDB Abbr. for "forced-draft blower."

FDC Abbr. for "fire-department connection."

FDN On drawings, abbr. for foundation.

FE Abbr. for fire escape.

FEA Abbr. for "Federal Energy Administration."

feasibility study A detailed investigation and
analysis conducted to determine the financial,
economic, technical, or other advisability of a
proposed project.

feather l.In joinery, a projection (tongue) on
the edge of a board which fits into the groove of
another board, as in a tongue and groove. Also
called a spline. 2. To produce a featheredge.

feather boarding A type of siding in which
the edge of one board overlaps a small part of the
board below it.

feather crotch Crotch veneer having a feathery
grain pattern.

featheredge An edge of a surface, surface coat-
ing, or surface film, which tapers away in fineness.

featheredge board A board made thin on one
edge, to overlap a part of the one next to it; also
called a clapboard.

featheredge brick Same as arch brick.

featheredged coping, splayed coping,
wedge coping Coping that slopes in only
one direction (not ridged or gabled).

featheredge rule A metal or wood straight-
edge for working plaster; used for straightening
angles. Usually about 2 to 6 ft (0.6 to 1.8 m)
long, with a tapered edge.

feathering 1. Same as foliation. 2. The cusps in
tracery.

feather joint A joint between two closely fitting
boards which have been squared and butted
against each other; a groove is cut along the length
of each board in which a common tongue is fitted.

feather joint

feather tip The thin, flimsy tip of a manufac-
tured wood shake, usually uneven or with bro-
ken corners, usually caused by improper sawing
of the shake.

feather tongue Same as cross tongue.

featured edge Of a gypsum board, the paper-
bound edge which provides special design or
performance.

Federal Housing Administration An
agency of the government of the US. which
insures loans made by private lending institu-
tions for the purchase, rehabilitation, or con-
struction of housing on private property.

Federal National Mortgage Association
(Fannie Mae) The quasi-private corpora-
tion chartered by the US government that func-
tions as a secondary mortgage market for private
residences.

Federal Revival A loose term denoting Amer-
ican architecture, primarily from about 1870 to
1970, that reuses aspects of, and attempts to
emulate, the earlier Federal style.

Federal style An architectural style in the
postcolonial era in America, from about 1780
to 1820 and beyond; noted for its clarity of
form, simplicity, restraint, and subtle use of
color, as well as its delicacy and lightness in
detailing; greatly influenced by the work of
Robert Adam (see Adam style). Buildings in
this style are usually characterized by: a sym-
metric facade, often with a giant entrance por-
tico (sometimes domed); commonly, brick
construction with a Flemish bond pattern and
thin mortar joints, or clapboard over timber
framing with corner boards; a belt course

392

feldspar

Federal style, facade (1796)

separating the first story from the second; a
cornice with moldings, friezes, quoins; classical
decorative elements such as festoons, garlands,
dentils, and egg-and-dart moldings; a side-
gabled, center-gabled, or hipped roof of moder-
ate pitch; a balustrade at the cornice line;
centrally located chimneys in the northern
states in America; exterior chimneys at the
ends of the house in the southern states; dou-
ble-hung windows; initially, stone lintels
above the windows, frequently, louvered win-
dow shutters; elaborate doorways, including
relatively thin columns, full-height pilasters,
or framing to form an entryway; a fanlight or a
row of rectangular panes over a paneled front
door, often with sidelights on each side of the
door. Often, little or no distinction is made

between the terms Federal style and Adam
style, as applied in the American colonies,
because of their strong similarities.
Fed Spec Abbr. for "Federal Specification."
fee Remuneration for professional work.

feebly hydraulic lime Lime obtained from
limestone containing a low percentage of clay.

feeder 1 . In power distribution, a group of elec-
tric conductors which originate at a main distri-
bution center and supply one or more secondary
distribution centers, one or more branch-circuit
distribution centers, or a combination of these.
2. In a water distribution system, a water pipe
connecting an appliance to the water supply
system.

feed barn Same as Yankee barn.

feed main A pipe supplying risers or cross mains.

feed pump A pump which supplies feed water to
a steam boiler.

feed water The water supplied to a steam boiler.

feeler gauge A series of blades of graduated
thickness; used to measure the clearance in a gap.

Federal style, door

feeler gauge

fee-plus-expense agreement Same as cost-
plus-fee agreement.

fee simple An inheritable, possessory interest
in land which may endure until the death of all
lineal and collateral heirs of the first owner and
which may be freely conveyed by its owner.

fee tail An estate of inheritance which is lim-
ited to one particular class of heirs of the person
to whom it is granted.

feint A slight bend in the edge of a flashing or
counterflashing to form a capillary break.

feldspar A group of igneous minerals, all of
which are softer than quartz, having the chemical

393

felt

composition of calcium silicates, potassium sili-
cates, or sodium-aluminum silicates.

felt An unwoven fabric, composed of fibers
which are matted together, usually with the aid
of moisture and heat, by rolling or by pressure;
usually manufactured from cellulose fibers from
wood, paper, or rags, or from asbestos or glass
fibers.

felt-and-gravel roofing See built-up roofing.

felting down Rubbing a dried paint or varnish
film with a wet felt pad and an abrasive, to lower
surface gloss.

feltwork Said of asphalt prepared roofing that
is built up to form a shaped surface; for example,
built to form a gutter slightly below the edge of
the roof.

felt nail Same as clout nail.

felt paper A type of building paper.

female connector In general, any type of
electrical connector having contacts which are
set into recessed openings.

female coupling A coupling with the threads
on the inside.

female thread Same as inside thread.

femerall See femerell.

femerell A ventilator, often louvered, drawing
smoke through a roof when no chimney is pro-
vided. Also see louver.

femur The long projecting face between each
channel of a triglyph.

fence A barrier that defines a property line,
encloses, or borders on a field, a yard, or the like.
For illustrations and definitions of specific types,
see barbed-wire fence, board fence, chain-link
fence, picket fence, plank fence, post-and-rail
fence, rail fence, split-rail fence, sunk fence, Vir-
ginia rail fence, worm fence, zigzag fence.

fencerow Planting which forms a fence or is
adjacent to a fence.

fender A protective curb or device, often of
timber.

fender post Same as bollard.

fender wall A dwarf wall built in a basement
under the hearthstone of a fireplace in the story
above.

fenestella 1 . A small glazed opening in a shrine
to afford a view of the relics. 2. A small niche
above a piscina or credence.

fenestella, 2

fenestra bifors The ancient equivalent of a
French window.

fenestral 1. A small window. 2. A framed win-
dow blind of cloth or paper used prior to the
introduction of glass.

fenestra method A procedure for predicting
the interior illumination provided by daylight
through windows.

fenestration The arrangement and design of
windows in a building.

fengite A type of translucent alabaster or mar-
ble, sometimes used for window panes in ancient
times.

feng»shui A traditional Chinese technique for
planning the layout of a building and for orient-
ing rooms within it, so as to be in harmony with
nature and with its surroundings.

fer a cheval In the Middle Ages, a fortifica-
tion having a curved parapet, placed so as to
defend a gateway.

feretory In a church, a space where major relics
are kept, often treated as a chapel behind the
main altar.

ferme ornee See cottage orne.

ferritic stainless steel A stainless steel having
a chromium content of 10.5 to 18% and a low
carbon content; it is magnetic and cannot be
hardened by heat treatment.

ferrocement, ferrocemento A composite
material consisting of a number of layers of wire
mesh embedded and interlayered with a cement-
sand mortar; provides a relatively thin, flexible,

394

field

tough membrane; has been used in experimental
structures and in fabricating complicated form-
work for repetitive concrete pours.

ferroconcrete See reinforced concrete.

ferrocyanide blue See Prussian blue.

ferrous metal Metal in which iron is the prin-
cipal element.

ferruginous Containing iron; such rocks indi-
cate the presence of iron by reddish-brown stains.

ferrule A metal sleeve, esp. one which is fitted
with a screwed plug; serves as an opening on the
side of a pipe providing access for inspection or
cleaning the interior of the pipe.

fertilizer That which fertilizes, i.e., acts as a
nutrient, whether organic or inorganic; may be
natural or artificial.

fertre Same as feretory.

festoon A festive decoration of pendant semi-
loops with attachments and loose ends, esp. a
swag of fabric, or representations of such decora-
tions. Also see garland.

festoon curtain, festoon drape A front cur-
tain on the stage of a theater; raised by lines
which pass through rings attached to the reverse
side; when raised, the curtain remains partly vis-
ible, hanging in swags and framing the stage.

festoon lamp A small incandescent lamp hav-
ing a tubular bulb and a base at each end.

festoon lighting Lighting by festoons of lamps
connected by flexible electric wire.

festoon staining A form of pattern staining on

exterior walls of a building; is usually caused by dif-
ferences in the flow of rainwater over the surface.

festoon tab A diagonally drawn festoon curtain.

FG l.Abbr. for "flat (slash) grain." 2.Abbr. for
"fine grain."

FH l.Abbr. for "fire hose." 2.Abbr. for "flat
head."

FHA Abbr. for Federal Housing Administration.

FHC Abbr. for "fire-hose cabinet."

FHWA Abbr. for "Federal Highway Adminis-
tration."

fiberboard A building material, usually com-
posed of wood fiber or cane or other vegetable
fiber, compressed with a binder into sheet form;
the physical characteristics depend on the fiber,
binder, density, and surface finish. Also see

hardboard, medium-density fiberboard, board
insulation.

fibered plaster Gypsum plaster containing
fibers of hair, glass, nylon, or sisal.

Fiberglas A proprietary name for fiberglass.

fiberglass, fibrous glass, glass fiber Fila-
ments of glass, formed by pulling or spinning
molten glass into random lengths; either gath-
ered in a wool-like mass or formed as continuous
thread-like filaments having diameters in the
range of 10 to 30 (J.m. The wool-like material is
processed into many forms of varying densities
for use as thermal and acoustical insulation. The
continuous-filament type is used for textiles,
glass fabrics, and electrical insulation and as
reinforcement for other materials.

fiberglass cloth See glass cloth.

fiber house Same as brush house.

fiber optical system A system for conveying
light through optical fiber cable, usually by the
transmission of coherent light.

fiber-reinforced concrete See fibrous con-
crete.

fiber saturation point When drying or wetting
wood, the point at which the wood fibers are sat-
urated but there is no water in the cell cavities.

fiber stress The longitudinal compressive or
tensile stress in a member, such as a beam.

fibre See fiber.

fibrous concrete Concrete containing asbes-
tos, spun glass, or other fibers to reduce unit
weight and improve tensile strength.

fibrous glass See fiberglass.

fibrous plaster, stick-and-rag work Cast
plaster which has been reinforced with canvas,
excelsior, etc.

fiddleback, cross figure, cross fire, ripple
figure Abrupt, curly figures in wood, particu-
larly maple and mahogany, caused by undula-
tions in fiber alignment.

fiducial mark In surveying, an index line or
point, used as a basis of reference.

fief In feudal England, the tenure of land or an
estate subject to the feudal obligation of service
and homage to the lord of the estate.

field 1. The central portion of a panel that is
thicker than its edges, so that it projects above
the surrounding frame or wall surfaces. 2. That

395

field bending

portion of the upper part of a wall between the
cornice and dado or between the frieze and
dado.

field bending The bending of steel reinforcing
bars on the job rather than in a fabricating shop.

field check 1. At a field site, a survey of exist-
ing conditions; also called a "field observation."
2. At an existing structure, a comparison of
dimensions with those shown on drawings; also
called "field measure."

field concrete Concrete delivered to, or
mixed, placed, and cured on the job site.

field-cured cylinders Test cylinders of con-
crete, cured as nearly as practicable in the same
manner as the concrete in the structure, to indi-
cate when supporting forms may be removed,
additional construction loads imposed, or the
structure placed in service.

field drain Same as agricultural pipe drain.

fielded panel See raised panel.

field engineer A term used by certain govern-
mental agencies to designate their representative
at the project site. Also see project representative.

field house A large, long-span structure used
for athletic activities such as basketball or track
events.

field impact insulation class (FIIC) A

single-number rating of the insulation against
impacts, provided by a floor (and associated
structures) derived from field impact sound mea-
surements in accordance with ASTM Test
Method E989.

field joint A connection between adjoining
members or parts, made at the time of installation.

field measure See field check, 2.

field-molded sealant A liquid or semisolid
material molded into the desired shape in the
joint where it is installed.

field observation See field check, 1.

field order A written order effecting a minor
change in the work, 1 not involving an adjust-
ment in the contract sum or an extension of the
contract time, issued by the architect to the con-
tractor during the construction phase.

field painting The painting of structural
steel or other metals after they have been
erected and are in their final positions in the
construction.

field report A report that is prepared by the
architect, or his or her appointee, following a
periodic inspection at the job site during con-
struction; includes written information on the
progress of the job, and sketches and pho-
tographs where appropriate. Also see punch list.

field representative See project representa-
tive.

field rivet A rivet driven into a steel structure
during its erection.

fieldstone 1 . Loose stone found on the surface
or in the soil. 2. Slabby units, flat in the direc-
tion of bedding or lineation of the rock, and suit-
able for setting as dry-wall masonry. Glacial or
alluvial boulders and cobbles, found in or on the
soil, are not fieldstone in the strict sense.

field sound transmission class (FSTC) A

single-number rating of the sound insulation
(provided by a partition), as measured in build-
ings in accordance with an appropriate standard.

field supervision That portion of the archi-
tect's supervisory work which is done at the con-
struction site.

field tile Same as drain tile.

field work Work done at the job site.

figure Pattern and natural markings in a wood
surface formed by an unusual arrangement or
color of the wood fibers and rays. These devia-
tions produce such figures as blister, bird's-eye,
fiddleback, etc.

figure dimension A dimension that is indi-
cated numerically on a drawing.

figured glass Translucent sheet glass, rolled
with a pattern in bas-relief on one face; light
transmission is high; degree of obscurity varies,
depending on pattern.

FIIC Abbr. for field impact insulation class.

filament An incandescent lamp filament whose
form and construction are designated by a letter: S,
straight wire; C, coil; CC, coiled coil.

filament lamp See incandescent lamp.

file A metal (usually steel) tool having a rect-
angular, triangular, round, or irregular section
and either tapering or of uniform width and
thickness, covered on one or more of its surfaces
with teeth or oblique ridges; used for abrading,
reducing, or smoothing metal, wood, or other
materials.

396

fillet

tm J <

POINl

:■, i

SINGLE- DOUBLE-
CUT CUT

COARSE

file: nomenclature

filigree Ornamental metal openwork of intri-
cate design.

fill l.Soil, crushed stone, or waste materials,
used to raise an existing grade or as a man-made
deposit. 2. The depth or the volume of such
material so added. 3. A cementitious material
such as concrete or terrazzo, which is placed
over a metal substructure to provide the wear-
ing surface of a tread or platform. 4. Aggregate

placed on a roof decking, 2 to form the appro-
priate design slope.

filled-cell masonry Wall construction made

with hollow masonry units in which all vertical
cells and voids are filled by pouring grout, 1 into
them.

filler 1 . A fine mineral aggregate used as an exten-
der to improve the properties of coating asphalt
and plastic asphalt cement. 2. Finely divided inert
material (such as pulverized limestone, silica, or
colloidal substances) sometimes added to portland
cement paint or other materials to reduce shrink-
age, improve workability, or act as an extender. 3.
A pigmented paste, sometimes colored, rubbed
into open-grained wood surfaces to fill the pores
prior to finishing. 4. An inert material added to
synthetic resin adhesives to improve their proper-
ties or reduce cost. 5. A plate which is inserted
merely to fill up space; a filler plate. 6. In painting,
a composition (often pigmented) used to fill pores
or irregularities in a surface in preparation for the
application of another coating.

filler block A concrete masonry unit used to
fill in between joists or beams, providing a plat-
form for a cast-in-place concrete slab.

filler coat A coat of paint, varnish, etc., used as
a primer.

filler metal Metal which is added during a
weld; has a melting point either approximately
the same as or below that of the metals being
welded.

filler plate 1. A blank plate used to fill mortised
cutouts. 2. A steel plate used to fill an open space
between structural members or parts thereof.

fillet l.A molding consisting of a narrow flat
band, often square in section; the term is loosely
applied to almost any rectangular molding; usu-
ally used in conjunction with or to separate
other moldings or ornaments, as the stria
between the flutes of columns. Also see band,
lattice molding, fret, reglet, annulet, supercil-
ium, taenia, cincture, cimbia, fascia, and plat-
band; a listel, or tringle. 2. A carved ornament
representing a flowing band or ribbon. 3. In stair
construction, a thin narrow strip of wood which
fits into the groove of the stair shoe or subrail
between balusters. 4. A cant strip. 5. A concave
junction where two surfaces meet. (See illustra-
tion p. 398.)

397

fillet chisel

LEVELING
BOARD

fillet, 1

fillet chisel A mason's chisel used in the fine
shaping of stone enrichments and details.

fillet gauge, radius gauge A gauge used to
determine the radius of curvature of small con-
cave or convex surfaces.

fillet gutter A narrow gutter on the slope of a
roof against a chimney or the like, formed of
sheet metal turned over a fillet of wood.

fillet joint A sealant that serves as a draft bead,
often triangular in section, when installed around
window panes.

fillet weld A weld of approximately triangular
cross section joining two surfaces, approximately
at right angles to each other, as in a lap joint.

TOE OF WELD

fillet weld

filling 1 . The application of a filler to fill cracks,
dents, and other surface imperfections. 2. Same
as infilling.

filling-in piece Any timber which is shorter
than similar members, as a jack rafter.

filling knife A knife with a flexible blade used
to apply a mastic or paste as a filler, 3.

filling piece A piece of material inserted on
or into another to provide a continuous surface.

fill insulation 1 . Any thermal insulation placed
in cavities of an assemblage. Also see granular-fill
insulation, loose-fill insulation, batt insulation,
blanket insulation. 2. Any loose insulation that
may be poured in place. Also see loose-fill insula-
tion, granular-fill insulation.

INSULATION

CEILING
JOIST

VAPOR
BARRIER

fill insulation being placed between joists

fillister l.A rabbet on the outer edge of a
muntin to hold the glass and putty. 2. A plane
for grooving timber.

fill lighting Supplementary illumination used
to reduce shadows or the range of contrasts.

fill pump A pump that supplies water to a grav-
ity tank or to a pressurized storage tank; is usu-
ally of the centrifugal type because this type is
readily available in a wide range of characteris-
tics.

fill-type insulation Same as fill insulation.

fill wire Same as shute wire.

film A layer of one or more coats of paint or var-
nish covering an object or surface.

film glue A thin sheet of paper or scrim impreg-
nated with a thermosetting resin; used to elimi-
nate glue bleed-through in bonding expensive
decorative veneers or in hot-pressing nonporous
laminates.

filter 1. A device to separate solids, such as dust,
from air. 2. A device to separate solids from liq-
uids. 3. A charcoal filter. 4. A layer or combina-
tion of layers of pervious materials designed and
installed in such a manner as to provide
drainage, yet prevent the movement of soil par-
ticles due to flowing water. 5. See heat filter. 6.
See light filter.

filter bed A bed of gravel, sand, or the like used
to filter water or sewage; also see sand filter.

filter block A hollow, vitrified clay masonry
unit, sometimes salt-glazed, designed for trick-
ling filter floors in sewage disposal plants.

filtration The removal of solids and/or bacteria
from water by a mechanical process in which sus-
pended solid contaminents are removed, e.g., by
passing it through a filter bed, sieve, or the like.

398

fine-textured

fin 1. An extended surface used to increase the
heat transfer area, as metal sheets attached to
tubes. 2. A thin flange projecting outward from
the periphery of the frame of an aluminum win-
dow to serve as a means of securing the frame in
a wood or masonry opening. 3. A narrow linear
projection on a formed concrete surface, result-
ing from mortar flowing out between spaces in
the formwork. 4. A thin projection on a casting
or forging resulting from trimming or from the
metal under pressure being forced into hairline
cracks in the die or around die inserts. 5. A steel
sheeting wall which projects from a main coffer-
dam structure.

FIN. On drawings, abbr. for finish.

final acceptance The owner's acceptance of a
project from the contractor upon certification
by the architect that it is complete and in accor-
dance with the contract requirements; final
acceptance is confirmed by the making of final
payment unless otherwise stipulated at the time
of making such payment.

final account The final payment for a con-
struction contract in the amount of the entire
unpaid balance.

final backfill The material used in filling a
trench, from bedding to the finished surface.

final certificate Authorization for final pay-
ment to be made by the owner to the contractor;
also see certificate for payment.

final completion The completion of work and
all contract requirements by the contractor.

final design Those design services provided
after completion of the preliminary design.

final filter See afterfilter.

final grade Same as grade level.

final grind See polish grind.

final inspection The final review of the proj-
ect by the architect prior to his issuance of the
final certificate for payment.

final payment Payment made by the owner to
the contractor, upon issuance by the architect of
the final certificate for payment, of the entire
unpaid balance of the contract sum as adjusted
by change orders.

final prestress See final stress, 1.

final set A degree of stiffening of a mixture of
cement (or concrete or mortar) and water

greater than the initial set; generally stated as
the time required for cement paste to stiffen suf-
ficiently to resist the penetration of a weighted
test needle.

final setting time The time required for a
freshly mixed cement paste, mortar, or concrete
to achieve final set.

final stress 1. In prestressed concrete, the stress
which exists after substantially all losses in stress
have occurred. 2. The stress in a member after
all loads have been applied.

fine aggregate 1. Aggregate which passes
through a 9.51 -mm (%-in.) sieve, passes almost
entirely through a 4-76-mm (No. 4) sieve, and is
predominantly retained on a 74-|!m (No. 200)
sieve. 2. That portion of an aggregate which
passes through a 4-76-mm (No. 4) sieve and is
predominantly retained on a 74-|lm (No. 200)
sieve.

fine grading Precise grading of ground after
rough levels have been reached, to prepare for
seeding, planting, or paving.

fine-grained See fine-textured.

fine-grown See fine-textured.

fine mineral surfacing Inorganic material
that is insoluble in water; used to surface roofing
products.

fineness l.A measure of particle-size distribu-
tion. 2. In paints, a measure of the size of pigment
particles.

fineness modulus A measure of the fineness
of an aggregate; a factor obtained by adding the
total percentages of an aggregate sample retained
on each of the following sieves and dividing the
sum by 100: No. 100 (150 Urn), No. 50 (300 |im),
No. 30 (600 urn), No. 16 (1.18 mm), No. 8 (2.36
mm), No. 4 (4.75 mm), % inch (9.5 mm), % inch
(19.0 mm), I/2 inch (38.1 mm).

fines l.In plastering, small aggregate which
passes through a 74-|lm (No. 200) sieve. 2. Soil
which passes through a 75 -Jim (No. 200) sieve.
3. A by-product of the processing of rock; varies
in particle size from powder or dust to silt or sand.

fine sawn Said of a sawn timber having rela-
tively smooth faces.

fine stuff In plastering, lime putty used in the
finish coat.

fine-textured, fine-grained, fine-grain,
fine-grown Descriptive of wood of uniform

399

finger guard

texture having small closely spaced pores or

cells.
finger guard A strip of soft material applied to

the edges of a doorjamb; used to prevent possible

injury to fingers inserted between door and jamb

during closure.
finger joint A heading joint having interlaced,

finger-like projections on the ends of the joined

members.

finger joint

finger plate Same as push plate.
fingers A drag, 1.

finial An ornament which terminates the point
of a spire, pinnacle, etc. Also see acroterion,
crop, knob, 2, pineapple, pommel.

fining off Applying a finish coat.

finish 1 . The texture, color, and smoothness of a
surface, and other properties affecting appear-
ance. 2. The texture and smoothness of a con-
crete surface after compacting and finishing
operations have been performed. 3. A finish
coat. 4. See finishing.

finish and color selection log Essential
information contained in the product informa-
tion notes, including a description of the appli-
cation of the finishes.

finish builders' hardware See finish hard-
ware.

finish carpentry Same as joinery.

finish casing The finish material around a casing.

finish coat, fining coat, finishing coat, set-
ting coat, skimming coat, white coat
The final or last coat of plaster, which pro-
vides a decorative surface or a base for decoration,
usually about to Vn in. (1.6 to 2.4 mm) thick.

finished grade Same as finish grade.

finished size Same as dressed size.

finished stair string See face string.

finials

finished stone Stone that has been dressed on
one or more of its surfaces.

finished string Same as face string.

finish floor, finished floor The floor, usually
laid over a subfloor, which provides the com-
pleted floor surface.

finish flooring The material used for the finish
floor surface, such as hardwood, terrazzo, tile, etc.

finish flooring level The surface level of a
floor which is laid over the subfloor.

finish grade The top surface of lawns, walks,
and drives, or other improved surface after com-
pletion of construction or grading operations.

finish hardware Same as architectural hard-

400

fire assembly

finish hardware, architectural hardware,
builders' finish hardware, finish builders'
hardware Hardware, such as hinges, locks,
catches, etc., that has a finished appearance as
well as a function, esp. that used with doors, win-
dows, and cabinets; may be considered part of the
decorative treatment of a room or building.

finishing Leveling, smoothing, compacting,
and otherwise treating surfaces of fresh (or
recently placed) concrete or mortar to produce
desired appearance and texture.

finishing brush A brush used to apply water to
a lime-putty finish as the finish is being water-
troweled.

finishing carpentry Same as joinery.

finishing coat See finish coat.

finishing compound A compound specifi-
cally designed to provide a smooth, level surface.

finishing hardware See finish hardware.

finishing hydrated lime A hydrated lime
which is suitable for application as a finish coat.

finishing machine A power-operated ma-
chine used to give the desired surface texture to a
concrete slab.

finishing nail A slender nail made from finer
wire than the common nail; has a brad-type
head which permits it to be set below the surface
of the wood, leaving only a small hole which can
be puttied easily; used in finishing work.

□ """"I

finishing nail

finishing off In joinery, preparations for a fin-
ish surface.

finishings The treatment of all surfaces in a
building and the addition of those fixtures
required to convert a carcass into a complete
building; does not include building services.

finishing sawhorse Same as sawhorse.

finishing tool A small tool, such as a float or
trowel, used in finishing a plaster surface.

finishing trades Those trades that involve the
finishing of surfaces in a building, such as floor-
ing, painting, plastering, and tiling.

finishing varnish See floor varnish.

finish lime, finishing lime See building lime.

finish plaster Same as finish coat.

finish plate See armored front.

finish size, finished size The overall size,
including trim, of any completely finished com-
ponent or article.

finish string See face string.

finish tile Tile with a face that may be used as a
finished wall surface.

fin wall A cavity wall that obtains added strength
by connections to a series of equally-spaced piers.

Fink truss, Belgian truss, French truss A
symmetrical truss, esp. used in supporting large
sloping roofs; in the form of three isosceles trian-
gles — one in the center with its base along the
horizontal tie, and each of the outer two having
its base along the sloping sides of an upper chord.

finned tube A metal tube having fins (i.e.,
metal plates, jointed to the tube, perpendicular
to its length) to transfer heat from the tube to
the surrounding air.

/^A^v,

Fink truss, above; long-span Fink truss, below

fir A softwood of the temperate climates includ-
ing Douglas fir, white fir, silver fir, balsam fir,
etc.; used for framing, interior trim.

fire alarm box A small box, usually red, hav-
ing a thin sheet of glass or plastic which, if bro-
ken, activates a fire alarm system.

fire alarm system l.An electrical system
which is installed in a building as a protective
measure against fire; sounds an alarm when
actuated by a fire-detection system. 2. An
alarm system designed to signal the presence of
a fire.

fire and extended coverage insurance
See property insurance.

fire area Any area in a building, encompassed by
fire walls and/or exterior walls, within which a fire
would be confined because of the surrounding fire-
resistant construction.

fire assembly The assembly of a fire door, fire
window, or fire damper, including all required

401

fireback

hardware, anchorage, frames, and sills. Also see
self-closing fire assembly.
fireback, chimney back The back wall of the
fireplace, constructed of heat-resistant masonry
or ornamental cast or wrought metal, which not
only is decorative but radiates heat into the room.

fireback of cast iron

fire block A fire stop.

fire box That part of a fireplace where combus-
tion takes place.

fireboard, chimney board, summer piece

A board or shutter-like device to close the open-
ing of a fireplace when not in use.

firebreak 1. Space between buildings, groups of
buildings, or areas of a city designed to prevent the
spread of fire from one building, group, or area to
another. 2. Fire-resistive floors, walls, doors, shut-
ters, etc., designed to prevent the spread of fire
within a building.

fire brick Brick made of refractory ceramic
material which will resist high temperatures;
used to line furnaces, fireplaces, and chimneys;
usually contains a high percentage of silica.

fire bridge A low wall of firebrick which sepa-
rates the furnace from the hearth in a reverber-
atory furnace.

fire canopy A horizontal, fire-resistive construc-
tion which extends beyond the vertical line of an
exterior wall; designed to prevent flames from a
window from igniting the contents of floors above.

fire cement A cementitious bonding material,
such as calcium aluminate cement, esp. com-
pounded for laying refractory brick.

fire certificate A certificate, issued by the appro-
priate fire officials, that certifies that all fire safety
requirements in a building have been met.

fire check door See fire door.

fire clay Clay having a melting point above
1600 degrees centigrade, especially used for
making fire bricks.

fire command station The principal loca-
tion where the status of a fire-detection system,
an alarm system, and a communications-and-
control system are displayed, and from which all
systems can be manually controlled.

fire compartment 1. An area of a building
enclosed within a fire-resistive construction; has
fire-resistive doors that close automatically in case
of fire. 2. Within a building, a space enclosed by
barriers of fire-resistive construction on all sides.

fire control Limitation of the size of a fire by (a)
distributing water so as to decrease the rate of
heat release, (b) pre-wetting of adjacent com-
bustibles, and (c) controlling the gas temperature
of the ceiling to avoid structural damage.

fire control damper A device which is designed
to close an air duct in the event of fire.

fire control room Same as fire command
station.

fire cracks See crazing, checking.

fire curtain See asbestos curtain.

fire cut A diagonal cut on a joist where it enters a
masonry wall; if the joist burns through some-
where along its length, injury to the wall is pre-
vented.

fire damper A damper which closes off an air
duct automatically in the event of fire so as to
restrict the passage of fire and smoke.

fire damper

402

fire-extinguishing system

fired brick A brick that has been treated in a
kiln at a high temperature (i.e., burnt), in con-
trast to one that has been air-dried.

fired clay tile Same as ceramic tile.

fired glass Glass having a permanent color, as a
result of firing ceramic coloring on the glass sur-
face at a high temperature.

firedog One of a pair of supports for logs in a
fireplace; also called an andiron.

fire department inlet connection A piping
connection through which the local fire depart-
ment can pump water into a standpipe system or
sprinkler system in a building.

fire department standpipe system A dry
standpipe system having no permanent water
supply; the fire department supplies water to
the system through a fire department connec-
tion.

fire detection system A system of sensors and
associated interconnected equipment which
detects the presence of fire and provides a warning
signal.

fire division wall In fire-resistant construc-
tion, a wall which separates a building into fire
areas, restricting the spread of fire.

fire door l.A fire-resistive door assembly,
including frame and hardware, which is capable
of providing a specified degree of fire protection
when closed. Usually provided with an auto-
matic closing mechanism, in the event of fire. 2.
In a furnace, the doorway through which fuel is
supplied.

fire-door assembly The combination of a fire
door and its accessories, such as its hardware and
closing devices and their anchors; includes the
doorframe and its anchors.

fire-door hardware Door hardware that has
been tested to establish its fire-door rating.

fire-door rating A fire-endurance rating for
doors, shutters, etc., established by the Under-
writers' Laboratories, Inc., or other recognized
and approved laboratory: class A: 3 hr; for door-
ways or other openings through a wall separat-
ing buildings or dividing a single building into
fire areas; class B: 1 or VA hr; for doorways or
other openings in enclosures of vertical trans-
portation through buildings (stairs, elevators,
etc.); class C: % hr; doors in corridor and room
partitions; class D: V/i hr; doors and shutters in

exterior walls which are subject to severe fire
exposure from outside the building; classes E and
F: % hr; doors, shutters, or windows in exterior
walls which are subject to moderate or light fire
exposure respectively from outside the building.

fired pin A hardened steel nail which is fired
into concrete by a stud gun, or the like.

fired strength Of a refractory concrete, the
compressive or flexural strength determined after
the first firing to a specified temperature for a
specified period of time and subsequent cooling.

fire draft stop See fire stop.

fire endurance The elapsed time during
which a material, assembly, or construction pro-
vides resistance against the passage of fire (or
excessive heat) through it under specified condi-
tions of test and performance.

fire escape A continuous, unobstructed path of
escape from a building for use in case of fire.

fire-escape window, emergency-exit win-
dow 1 . Any window which opens onto a fire
escape. 2. A window at ground level which is
designed to open wide, as a door, for emergency
exits.

fire exit See fire escape.

fire-exit bolt See panic exit device.

fire exposure The subjection of a material or
construction to a high heat flux from an external
source, with or without flame impingement.

fire extinguisher A portable device, for
immediate and temporary use in putting out a
fire: class A: used on fires involving ordinary
combustible materials (such as wood, cloth,
paper, rubber, and many plastics), which require
the cooling effects of water or certain dry chem-
ical coatings to retard combustion; class B: used
on fires involving liquids, gases, greases, etc.,
extinguished most readily by excluding air or
inhibiting the release of combustible vapors;
class C: used on fires in "live" electrical equip-
ment; class D: used on fires involving certain
combustible metals, such as magnesium, sodium,
etc., requiring a heat-absorbing extinguishing
medium not reactive with the burning metals.

fire-extinguishing system An installation
of automatic sprinklers, foam nozzles, fire hoses,
and/or portable fire extinguishers, designed to
provide adequate fire-extinguishing capability
for a room or building.

403

firehood

firehood A metal cover or cowl (or equivalent
masonry configuration) over a hearth or stove
that directs smoke to the flue.

fire frame A cast-iron housing, permanently
installed in a large fireplace opening to reduce its
size.

fire grading The fire-hazard classification of a
building or structure, usually specified in hours;
see fire-protection rating.

fire hazard The relative danger that a fire will
start and spread, that smoke or gases will be gen-
erated, or that an explosion will occur, potentially
endangering the lives and safety of the occupants
of the building. Also see hazardous area.

fire-hazard classification One of three des-
ignations: ordinary, high, or low. Based on the
contents and operations conducted in the build-
ing or structure, or on the flame-spread rating of
its interior finishes or appurtenances.

fire hose A large-diameter hose which is usu-
ally wound on a cylindrical spool mounted on a
wall of a building; this combination enables the
hose to be pulled out quickly to fight a fire.

fire hydrant, fireplug A supply outlet from a
water main, for use in case of fire.

fire hydrant

fire integrity In a piece of construction mate-
rial, the quality that prevents fire on one side of
the material from being transmitted to the oppo-
site side within a designated time period.

fire limits A boundary line establishing an area
in which there exists, or is likely to exist, a fire
hazard requiring special fire protection.

fire line l.A system of pipes and equipment
used exclusively to supply water for extinguish-
ing fires. 2. A fire hose, particularly when in use
for fire fighting.

fire load The total fuel contributed to a fire by
a building's contents, combustible materials used
in its construction, and/or its finishes.

fire load, fire loading 1. The combustible con-
tents or interior finish of a building per unit floor
area, often expressed as pounds per square foot or
as Btu per square foot. 2. The amount of fuel within
a building which has the potential of burning and
releasing heat to feed the growth of a fire.

firemark In colonial America, a plaque, usually
cast in lead and affixed to the facade of a house,
indicating that the owner of the house had con-
tributed money to the local volunteer fire
department.

firemark

fire main A water service pipe, 1 whose dedicated
use is fighting a fire; connects the public water sup-
ply to a terminating point in the building.

fire partition In a building, a partition which
has a fire-endurance rating of not less than 2 hr,
but does not qualify as a fire wall.

fire path An access route to a building provided
for fire engines and other vehicles in case of fire.

fire performance characteristic A response
of a product, material, or an assembly of such
products and/or materials to a prescribed source
of heat or flame under controlled fire conditions.

fireplace An opening at the base of a chimney,
usually an open recess in a wall, in which a fire
may be built.

fireplace cheeks The splayed sides of a fire-
place.

fireplace crane A wrought-iron horizontal
bar, once commonly attached to the rear wall of
a fireplace and pivoted so that it could be swung
out at any desired angle over the fire; often

404

fire resistance

served as a support from which to hang pots and
kettles. Also see randle bar and trammel,
fireplace damper A pivoted metal plate, set
just above the throat in a chimney, that controls
the draft, 1 (i.e., the flow of air and gaseous prod-
ucts) through a fireplace and up the chimney;
may be used to close off the chimney when the
fireplace is not in use.

FIREPLACE
FLUE LINER

FURNACE
FLUE LINER

DAMPER

SMOKE

SHELF

ASH

DUMP

OUTER
HEARTH

fireplace

fireplace lintel A horizontal structural mem-
ber that supports the weight of the wall above a
fireplace opening; same as manteltree. If wood, it
is often plastered to increase its fire resistance; if
metal, it is usually called a chimney bar.

fireplace mantel See mantel.

fireplace surround Around a fireplace, a
framing composed of bricks, elaborate tile, mar-
ble, or decorative woodwork.

fireplace throat Same as chimney throat.

fireplace tile Tile used as a decorative facing
around a fireplace opening; for example, Dutch
tile.

fire plug Same as fire hydrant.

fire point 1. See flash point. 2. The temperature
at which a fuel's vapors will sustain ignition.

fire-protected Said of premises that are pro-
vided with a fire-detection system and/or fire-
extinguishing system.

fireproof 1 . Descriptive of a material or construc-
tion which is unburnable, or almost so; an absolute
quality which does not exist; usually refers to a
material or construction which is highly fire-resis-
tant. 2. To apply a chemical solution to a material
as a fire retardant; to flameproof.

fireproof curtain See asbestos curtain.

fireproof door 1. A door composed entirely of
fireproof materials. 2. A metal-clad fire door;
also called a kalamein fire door.

fireproofing Material applied to structural ele-
ments or systems which provides increased fire
resistance, usually serving no structural func-
tion. Also see sprayed fireproofing.

fireproofing tile Tile designed for protecting
structural members against fire.

fire protection Materials, measures, and prac-
tices for preventing fire or for minimizing the
probable loss of life or property resulting from a
fire, by proper design and construction of build-
ings, by the use of detection and extinguishing
systems, by the establishment of adequate fire
fighting services, and by the training of building
occupants in fire safety and evacuation proce-
dures.

fire-protection equipment cabinet A cab-
inet to house hose, fire extinguishers, or the like.

fire-protection rating The time in hours, or
fractions thereof, that a material (or an assem-
blage of materials) can withstand fire exposure,
as determined by a fire test conducted in accor-
dance with applicable code requirements.

fire-protection sprinkler system See sprin-
kler system.

fire-protection sprinkler valve A valve used
as an automatic means of controlling the flow of
water in a fire-protection sprinkler system.

fire-protection system A system composed
of appropriate electrical devices, equipment, and
systems used to detect a fire, activate an alarm,
and suppress a fire if detected.

fire pump A pump especially designed, tested,
and listed for use in a fire suppression system.
Since it is rarely (if ever) used, it must be tested
periodically to ensure that its operating condi-
tion is satisfactory.

fire-rated door See fire-door rating.

fire resistance 1 . The capacity of a material or
construction to withstand fire or give protection

405

fire-resistance rating

from it; characterized by its ability to confine a
fire and/or to continue to perform a structural
function. 2. (Brit.) The ability of a component of
building construction to satisfy certain criteria,
specified by the BSI, for a stated period of time. 3.
According to OSHA: so resistant to fire that, for
a specified time and under conditions of a stan-
dard heat intensity, it will not fail structurally and
will not permit the side away from the fire to
become hotter than a specified temperature.

fire-resistance rating The time in hours that
a material or construction can withstand fire
exposure, as determined in conformity with gen-
erally accepted standards, or from information
derived from standard tests.

fire-resistive, fire-resistant, fire-resisting

Having fire resistance.

fire-resistive ceiling One having a fire endurance

rating of at least 1 hr.

fire-resistive construction A building con-
struction in which the structural members
(including walls, partitions, columns, floors, and
roof) are of noncombustible materials having
fire-endurance ratings at least equal to those
specified by the appropriate authorities.

fire-resistive wall A wall having a fire rating
in accordance with code or underwriters'
requirements governing its use; not necessarily
incombustible.

fire-retardant chemical l.A chemical or
chemical preparation used to reduce flammabil-
ity or to retard the spread of flame. 2. A chemical
which, when added to a combustible material,
delays ignition and combustion of the chemically
treated material when it is exposed to fire.

fire-retardant coating l.A material applied
to the surface of a building component to
increase its resistance to flaming combustion
along the surface. 2. A covering which is applied
(as a fluid) on a material to delay ignition and
combustion of the material.

fire-retardant finish Paint which contains
incombustible materials (such as chlorinated
waxes and resins, silicones, antimony oxide, and
other pigments) which form a protective layer
over combustible surfaces to retard the rapid
propagation of flame.

fire-retardant treatment The application of a
fire-retardant chemical or a fire-retardant coating.

fire-retardant wood Lumber and plywood

which has been impregnated, under pressure, with
mineral salts; in the event of fire, the burning
wood and salts emit noncombustible gases and
water vapor instead of the usual flammable vapors.

fire-retarding glazing l.Wire glass. 2. Cop-
perlight glazing.

fire riser See standpipe.

fire risk 1 . The probability that a fire will occur.
2. The potential for harm to life and damage to
property resulting from the occurrence of a fire.

fire risk assessment standard A standard-
ized method of assessing fire risk of a material,
product, or assembly in a specific environment
or application.

fireroom A term occasionally used in colonial
times in America for any room having a fireplace.

fire safety plan A description of the fire drill
and evacuation procedures for a building in accor-
dance with applicable administrative require-
ments.

fire screen Any screen set in front of a fire-
place to prevent flying sparks or embers from
entering the room.

fire section A sprinklered area within a build-
ing, separated from other areas by a noncom-
bustible construction having a fire-resistance
rating of at least two hours.

fire separation A floor or wall (either without
openings or with adequately protected open-
ings) having a fire-endurance rating required by
appropriate authorities; acts as a barrier against
the spread of fire within a building.

fire separation assembly A horizontal and/or
vertical fire -resistance-rated assembly of materi-
als having protected openings, and designed to
restrict the spread of fire.

fire-setting The removal of small flakes from the
face of brickwork or stone by means of a flame.

fire shutter A metal shutter (including frame
and hardware) which has a fire-endurance rating
required by code. The required rating depends
on the location and nature of the window or
opening in which it is installed.

fire tape In gypsum-board construction, the
tape that is used to seal a joint between two adja-
cent gypsum boards. See the illustration under
gypsum board.

406

fire wall test

fireside, ingleside The hearth or space about
the fireplace.

fire sprinkler A nozzle (sprinkler head) in a
fire protection system; distributes water in a spe-
cific spray pattern.

fire sprinkler system An integrated system of
underground and/or overhead piping, with one
or more automatic water supplies, to which fire
sprinklers (i.e., sprinkler heads) are attached
and placed in a systematic pattern; also called a
fire-protection sprinkler system.

fire stair A stair, enclosed in fireproof walls,
within the body of the building which it serves,
to which access may be had only through self-
closing fire doors.

fire standpipe See standpipe.

fire standpipe system See standpipe system.

firestat A thermostat in an air-conditioning sys-
tem; preset at a fixed temperature, usually 125°F
(52°C) in accordance with code or insurance
requirements.

fire stone Any stone, such as sandstone, that is
heat-resistant and therefore especially suitable
for use in fireplaces.

fire stop In a concealed, hollow construction,
a material or member which fills or seals the
open construction to prevent or retard the
spread of fire.

fire stop

fire-stopping The closing of all concealed
draft openings to form an effective fire barrier
at floors, ceilings, and roofs by means of brick,
concrete, gypsum, asbestos, mineral wool,
rock wool, metal lath with cement or gypsum
plaster, or other approved incombustible
materials.

fire suppression The marked reduction of the
rate of heat release of a fire and the prevention
of its regrowth by means of direct and sufficient
application of water through the fire plume to
the burning fuel surface.

fire suppression system A system used to
control or to extinguish a fire in a building. The
most common types are fire sprinkler systems
and standpipe systems.

fire terrace A level space or area at a setback
of an exterior wall of a building that is approxi-
mately the same elevation as that of the curb or
grade level of a street that is higher than the
building entrance; provides a safe termination
for fire escapes from the upper stories of the
building.

fire testing Standardized testing of materials
to determine their combustibility, their fire
risk assessment, and/or their flame-spread
index.

fire test exposure severity A measure of the
degree of fire exposure according to ASTM Test
Methods El 19, E152, and E163.

fire tower In a building, a vertical enclosure
(containing a stairway) having a fire-endurance
rating sufficiently high to qualify as a fire escape.

fire-tube steel boiler An integral steel-shell
boiler in which the combustion gases pass
through the tubes and the boiler water passes
around them; usually shipped in one piece, ready
for piping connections.

fire-tube test A standard test for the com-
bustible properties of treated wood; makes use of
a fire-tube apparatus specified by the ASTM.

fire vent Same as smoke and fire vent.

fire wall A wall so constructed as to prevent the
spread of fire from one part of a building to
another.

fire 'wall test A laboratory test to determine the
capability of a wall to withstand fire without fail-
ing structurally and without permitting extreme
heat to pass through it. Also see fire wall.

407

fire window

fire window A window and associated compo-
nents, including frame, wired glass, and hard-
ware, having a fire-endurance rating at least as
high as that specified for the location in which it
is to be used.

fire zone An area of a building that has been
designated by the applicable building code as
being subject to a relatively high fire risk.

fir fixed Said of unplaned timbers which are
fixed only by nails.

firing The controlled heat treatment of ceramic
ware in a kiln or furnace during the process of
manufacture to develop desired properties.

firing port Same as riflehole.

firmer chisel A carpenter's chisel with a blade
thin in proportion to its width, esp. used for
mortising.

firmer gouge A carpenter's gouge having its
bevel on the outside; similar in proportions to a
firmer chisel; esp. used in cutting grooves.

firring Same as furring.

first coat The initial application of plaster. In
two-coat work it is called the base coat; in three-
coat work it is called the scratch coat.

first fixings (usually pi.) Hidden blocks of
wood, grounds, or plugs to which joinery is
fixed.

first floor 1 . ( US ) The floor of a building which
is at, or closest to, grade level. 2. (Brit.) The
floor of a building which is next above the floor
at, or closest to, grade level; the latter is known
as the "ground floor."

first gallery In a theater, a seating area in a bal-
cony above a tier or tiers of boxes.

first mortgage A security interest in property
which takes precedence over all similar interests
in the same property.

First Period Colonial architecture A term
occasionally used for architecture of the Ameri-
can colonies from the time of their initial settle-
ment until the emergence of the Georgian
architecture at the beginning of the 18th cen-
tury; see American Colonial architecture.

first pipe In a theater stagehouse, the pipe bat-
ten immediately behind the proscenium; used to
support lighting equipment.

First Pointed Gothic See Early English archi-
tecture and Lancet style.

first story In the US, the lowest story of a
building which is entirely above the average
grade; the ground floor. In many European
countries, the first floor above the ground floor.

fish beam 1. A built-up timber beam composed
of two beams placed end to end and secured by
fish plates covering the joint on opposite sides.
2. Any beam having sides which swell like the
belly of a fish.

fish»bellied Descriptive of a girder or truss hav-
ing its bottom flange or chord convex downward.

fish bladder (fischblase) An ornamental
motif of the late Gothic tracery, reminiscent in
form of the air-bladder of a fish.

fish bladder tracery

fished joint A heading joint, 1 strengthened by
fishplates.

fisheye In plastering, a spot in the finish coat
approximately 'A in. (6.4 mm) in diameter, caused
by lumpy lime.

fish glue A glue made from fish skins and blad-
ders; similar to animal glue.

fish 'wire A wire used to pull an electrical con-
ductor through a conduit, 1 .

fishing wire Same as snake, 1.

fish joint See fished joint.

fish mouth In built-up roofing systems, an
opening where one felt layer overlaps another;
caused by a wrinkle at the overlapping edge.

408

fixed-ended

fishplate A wood or metal piece used to fas-
ten together the ends of two members with
nails or bolts.

B0° 80°

fishplates

fishscale pattern Overlapping rows of shaped
tiles or shingles that resemble overlapping fish
scales; see imbrication.

fishtail A wedge-shaped piece of wood used as
part of the soffit form between tapered end pans
in concrete joist construction.

fishtail bolt A bolt having a split end; embed-
ded in concrete, or the like, for use as an anchor.

fish tape Same as snake, 1.

fishtail tie A metal bar whose ends are split and
twisted; said to resemble the tail of a fish.

fissured soil Compressed soil that tends to
fracture along a definite plane.

fistula In ancient Roman construction, a water
pipe of lead or earthenware.

fitch l.A small thin paintbrush with a long
wooden handle; used to reach recessed areas. 2.
A thin piece of wood, as a veneer. 3. A bundle of
veneers arranged in the same order as cut from
the log. 4. A board forming part of a flitch beam.

fitment 1. See fitting. 2. A bathroom fixture,
usually built-in.

fitting l.A pipe part, usually standardized, such
as a bend, coupling, cross, elbow, reducer, tee,
union, etc.; used for joining two or more sections
of pipe together. The term usually is used in the
plural. 2. An accessory such as a bushing, cou-
pling, locknut, or other part of an electric wiring
system which is intended to perform a mechani-
cal rather than an electrical function. 3. Same as
window hardware. 4. British for luminaire. 5. A
decorative or functional item or component in a
building which is fixed but not built in; also
called a fitment.

S^^ft

45- sanilaiy tee

fittings, 1

fit out, fit up To provide the tenants within a
building with building services, including heat-
ing, lighting, water supply, drainage services, gas
supply, electrical supply, fire protection, garbage
disposal services, waste disposal services, air-
conditioning, and security protection.

fitting-up Assembling the different members of
a structure and connecting them temporarily with
bolts preparatory to making the final connection.

fitting-up bolt An ordinary bolt used to hold
members together temporarily while they are
being permanently connected.

five-centered arch An arch whose intrados is
struck from five centers.

five-part mansion A pretentious colonial
home connected to a dependency on each side
of the house hyphens.

FIX. On drawings, abbr. for fixture.

fixed-bar grille In an air-conditioning system,
a grille most commonly used for return and
exhaust air openings; the position of the bars is
preset and nonadjustable.

fixed beam, fixed-end beam A structural
beam whose ends are fixed.

fixed-cost contract See fixed-price contract.

fixed-end column A column whose fixed
ends prevent it from rotating.

fixed-ended Said of a column or beam that is
rigidly restrained at the end supports so as to pre-
vent it from rotating.

409

fixed joint

fixed joint In a structural framework, a joint
that restrains a member from turning.

fixed light, deadlight, fast sheet, stand
sheet, fixed sash A window or an area of a
window which does not open; glazed directly in
a fixed frame that does not open.

fixed limit of construction cost The maxi-
mum allowable cost of the construction work as
established in the agreement between the owner
and the architect. Also see construction budget.

fixed-price contract A construction contract
between an owner and a contractor in which the
parties agree to carry out the terms of the con-
tract for a specified price; does not customarily
include the compensation paid to the architect
and consultants, or the cost of the land.

fixed retaining wall A retaining wall which is
rigidly supported at its top and bottom; can
withstand higher pressures than a freestanding
wall.

fixed sash A fixed light.

fixed transom An inoperable panel or glass
light over a door.

fixing 1 . Installing glass panes in a wall, partition,
or ceiling. (Installing glass in windows, doors,
storefronts, curtain walls, borrowed lights, etc., is
termed glazing.) 2. Same as ground, 1.

fixing block A lightweight concrete block that
is nailable.

fixing brick l.Same as nog. 2. A lightweight
brick that is nailable.

fixing compound A material used to hold a
pane of glass in an opening.

fixing fillet See ground, 1.
fixing pad Same as ground, 1.
fixing slip See ground, 1.
fixity See depth of fixity.

fixture l.Any item which was once tangible
personal property, but which by virtue of its
affixation to real property is deemed to be per-
manently merged into it. 2. An electrical device
which is secured to a wall or ceiling, and used to
hold lamps; a luminaire. 3. See plumbing fix-
ture.

fixture branch Any pipe which connects sev-
eral plumbing fixtures, such as a drain serving
two or more fixtures or a supply pipe between
the water-distributing pipe and several fixtures.

WATER CLOSET

f-SOII

LAVATORY

'j LAVA I

-L- FIXTURE
DRAIN

SOIL PIPE

FIXTURE BRANCH

SOIL STACK

fixture branch

fixture carrier A metal device designed to
support an off-the-floor plumbing fixture.

fixture clearance The distance between a
plumbing fixture and the nearest obstruction.

fixture drain The drain extending from the
trap of a plumbing fixture to a junction of that
drain with any other drainpipe.

fixture fitting A device used to control or
guide the flow of water into a fixture or to con-
vey water away from the fixture.

fixture joint An electric connection between
two conductors, formed by crossing their bare
ends, wrapping one end around the other, and
then folding them over.

FWTUftE WIRE >?

fixture joint

fixture supply The water-supply pipe connect-
ing a plumbing fixture to a branch water-supply
pipe or directly to a main water-supply pipe.

fixture trap Same as trap, 1.

fixture unit A measure of the probable dis-
charge into the drainage system by various types
of plumbing fixtures; expressed in units of cubic
volume per minute; the value for a particular fix-
ture depends on: its volume rate of drainage dis-
charge; the time duration of a single drainage
operation; and the average time between succes-
sive operations.

fixture-unit flow rate According to code, the
total discharge flow in gallons per minute of a
single fixture divided by 7.5, which provides the
flow rate of that particular plumbing fixture as a

410

flame resistance

unit of flow; fixtures are rated as multiples of this
unit of flow.

fixture vent A vent pipe which leads from the
drainage pipe to another vent pipe or to the
atmosphere.

fL Abbr. for footlambert.

FL 1. Abbr. for "floor line." 2. On drawings, abbr.
for floor. 3. On drawings, abbr. for flashing.

flabelliform Fan-shaped; said of an ornament
composed of palm leaves, or the like.

flag A flagstone.

flag lot A lot, often irregular in shape, which
provides little more street frontage than that
required for access by a vehicle.

flagging 1. Flagstone. 2. A surface paved with
flagstones. 3. The process of setting flagstones.

flagpole A pole on which a flag, banner, or
emblem may be raised and displayed.

flagstone, flag, flagging A flat stone, usually
1 to 4 in. (2.5 to 10 cm) thick, used as a step-
ping-stone or for terrace or outdoor paving; usu-
ally either naturally thin or split from rock that
cleaves readily; sometimes produced by sawing.

15th cent., characterized by flowing and flame-
like tracery.

flame A hot (usually luminous) zone of gas
and/or particulate matter in gaseous suspension
that is undergoing combustion.

flame cleaning The use of a hot flame on steel to
remove paint, mill scale, moisture, and surface dirt.

%HBBH

flagstone: paved walk

"■I ■!■'.-!,,.:■■:<.■,■: ,," ',.,■ ! £ , 1. ft '■-■ 1 '

,"■'"■■ .:■■— V ; '^ :;■;.■•, >■: ■■ ■ >■

Flamboyant style

flail A device for breaking or crushing material
by means of one or more hammers which are
hinged or pivoted about a rotating axle.

flake board Same as particleboard.

flaking The loss of adhesion and cohesion of a
paint film accompanied by peeling.

flambeau A luminaire resembling a flaming
torch.

flambe glaze A flow ceramic glaze with cop-
per, which produces a variegated effect.

flamboyant finish A decorative coating
achieved by applying transparent colored var-
nish or lacquer over a polished metal substrate.

Flamboyant style The last phase of French
Gothic architecture in the second half of the

flame»cut Said of a steel plate whose longitudi-
nal edges have been prepared by oxygen cutting.

flame cutting A metal-cutting operation in
which the separation of the metal is effected
with a torch. See also oxygen cutting and oxy-
acetylene torch.

flamed finish A rough-textured finish that
results from applying a flame to the surface of a
stone containing abundant silica. Also called
flame-textured finish.

flame front The leading edge of a flame propa-
gating through a gaseous mixture or across the
surface of a solid or liquid.

flame resistance The ability to withstand flame
impingement or to provide protection from it.

411

flame resistant

flame resistant Having flame resistance.

flame-retardant chemical Any chemical
which, when added to a combustible material,
delays ignition and reduces the spread of flame on
the resulting material.

flame-retardant coating A fluid-applied sur-
face covering on a combustible material which
delays ignition and reduces flame spread when
the covering is exposed to flame.

flame-retardant treatment The application
of a flame-retardant chemical or a flame-
retardant coating.

flame speed The rate of propagation of a flame
through a gaseous fuel-and-oxidizer mixture rel-
ative to a fixed reference point.

flame spread Flaming combustion along a sur-
face (not to be confused with the transfer of
flame by air currents).

flame-spread index A numerical designa-
tion, applied to a building material, which is a
comparative measure of the ability of the mate-
rial to resist flaming combustion over its surface;
the rate of flame travel, as measured under the
applicable ASTM test, in which a selected
species of untreated lumber has a designated
value of 100, and noncombustible cement-
asbestos board has a value of 0.

flame-spread rating A measurement of flame
spread on the surface of a material (or an assem-
blage of materials) as determined by procedures
described in the applicable code.

flame treating A method of rendering inert
thermoplastic objects receptive to inks, lac-
quers, paints, adhesives, etc., by bathing them
in an open flame to promote oxidation of the
surface.

flameproof coating A discontinued term;
replaced by flame-retardant coating.

flammability A material's ability to burn or
support combustion.

flammable Subject to easy ignition and rapid
flaming combustion.

flammable liquid Any liquid having a flash
point below 140°F (60°C) and having an
absolute vapor pressure not exceeding 40 lb per sq
in. (2.8 kg per sq cm) absolute at 100°F (37.8°C).

flanch, flaunch To widen and slant the top of
a chimney stack so that water is directed away
from the flue.

flange l.A projecting collar, edge, rib, rim,
or ring on a pipe, shaft, or the like. 2. One of
the principal longitudinal components of a
beam or girder which resists tension or com-
pression.

FLANGE

flange, 2

flange angle One of the component parts of
the top or bottom flange in a girder.

flange cut A cut in the flange of a beam or
girder to facilitate attachment or passage of
another element.

flanged joint A joint consisting of two com-
panion flanges, bolted together and made
leakproof by means of a gasket.

flange plate l.See cover plate, 2. 2. In a rail-
ing system, the flat piece between the end of a
railing (or railing element) and the adjoining
construction or supporting member.

flange splice A splice made in the flange of a
beam or girder.

412

flared post

flange union In plumbing, a pair of flanges

which hold two pipes together; the flanges are
screwed onto the ends of the pipes and then are
held together by bolts.

flange union

flank A side elevation.

flanked Said of a fortification that is defended
by another fortification.

flanker 1 . A dependency or a service wing on a
side of a building. 2. From a recess in the side of
a medieval bastion, a gun emplacement that
commanded the ramparts.

flanking transmission The transmission of
sound from one room to another by a path other
than directly through the partition which sepa-
rates the rooms.

CONTINUOUS
FLOOR SLAB

flanking transmission: path, indicated by arrow

flank wall A sidewall of a building in contrast

to the front or rear wall.
flank window, flanking window Same as

sidelight.

flanning The internal splay of a window jamb.

flap door A small door, hinged horizontally
along the bottom, that opens downward.

flap hinge See backflap hinge.

flap trap In plumbing, a trap having a hinged
flap which allows flow in one direction only, pre-
venting backflow.

flap valve In plumbing, a check valve in the
form of a hinged disk which permits flow in one
direction only.

flared brick A burnt brick that has dark patches
at an end as a result of having been placed too
near the fire during its treatment in a kiln.

flared eaves That part of a roof that has a grad-
ually diminishing slope and that projects beyond
the face of an exterior wall, flaring outward near
its lower end; common in rural Dutch Colonial
architecture.

flared eaves

flared joint A mechanical joint between two
pieces of copper or plastic tubing; made by flaring
one end of a tube in such a way as to receive a spe-
cial fitting which fits in the flare; may be taken
apart and reassembled without difficulty; especially
useful in areas where fire hazard will not permit the
open flame required in soldering or brazing a joint.

flared post A heavy post, often located at the
corners of a timber-framed house, that has a flare
at its upper end to provide a larger area for sup-
porting the load imposed on it from above; occa-
sionally located at the middle of a wall to
provide additional support for a massive sum-
merbeam. (See illustration p. 414.)

413

flare fitting

flared post

flare fitting A mechanical connection used
with soft-metal tubing; one end of a tube is
flared and provided with a mechanical seal.

flare header In masonry, a header of darker
color than the field of the wall.

flash 1 . A color variation on the surface of a
brick, produced intentionally or otherwise, due
to surface fusion or vitrification of a film of dif-
ferent texture. 2. Abbr. for flashing.

flash chamber A tank between the expansion
valve and evaporator in a refrigeration system to
separate and bypass any flash gas formed in the
expansion valve.

flash coat A light coat of shotcrete over a con-
crete surface to cover minor blemishes.

flash»coved Same as self-coved.

flashing A thin impervious material placed in
construction (e.g., in mortar joints and through
air spaces in masonry) to prevent water penetra-
tion and/or provide water drainage, esp. between
a roof and wall, and over exterior door openings
and windows.

GLASS PANE

WINDOW

JAMB

flashing block A specially designed masonry
block having a slot or channel into which the
top edge of a counterflashing may be inserted
and anchored. Also see raggle, 1.

flashing board A board to which flashings are
fixed.

flashing cement A mixture of bitumen, a sol-
vent, and inorganic reinforcing fibers, such as
glass or asbestos fibers; applied with a trowel.

flashing compound See flashing cement.

flashing ring A collar around a pipe to secure
it as it passes through a wall or floor.

flash point The minimum temperature of a
combustible material at which there is sufficient
vaporization to produce a combustible mixture
with air if ignited by a flame.

flash set, grab set, quick set The rapid devel-
opment of rigidity in a freshly mixed portland
cement paste, mortar, or concrete, usually with
the generation of considerable heat; this rigidity
cannot be dispelled, nor the plasticity regained by
further mixing, without the addition of water.

flash 'welding A resistance welding process in
which metals are joined as a result of heat,
obtained from the resistance to an electric cur-
rent between the metal surfaces, and subsequent
pressure.

flat 1 . Descriptive of a roof, etc., having little
or no slope. 2. One floor of a multistory build-
ing or a dwelling unit on one floor. 3. Descrip-
tive of paint having very low gloss. 4. A piece
of framed stage scenery without thickness other
than its framing members. 5. A metal bar hav-
ing a rectangular cross section; if fabricated of
steel, must have a minimum thickness of 0.203
in. (0.516 cm) and a maximum width of 8 in.
(20.3 cm).

flat arch An arch whose soffit (i.e., lower face)
is horizontal. Also called a Dutch arch, French
arch, jack arch, or straight arch.

FLASHING £

flashing

flat arch

414

flat spray sprinkler

flat arris An arris (i.e., the external angular
intersection of two surfaces), such as between
two flutes of a Doric column, which has been
flattened so that it is not sharply defined.

flat band A flat, undecorated impost.

flat-chord truss A truss in which the top and
bottom chords are approximately flat and parallel.

flat coat An intermediate coat of paint used as
a base for a topcoat; a filler coat.

flat cost The cost of materials and labor with-
out overhead or profit.

flat cutting See ripsawing.

flat-drawn glass, flat-drawn sheet glass
See drawn glass.

flat enamel brush A paintbrush, about 2 to
3 in. (5 to 7.5 cm) wide, having flagged and
tapered bristles; used to apply smooth films of
enamel on woodwork. Also see flat wall brush.

flat glass See window glass, plate glass, float
glass, rolled glass, sheet glass.

flat-grained See plain-sawn.

flat ground edge An edge of a light, 2 that has
been ground flat and is perpendicular to the glass
surface.

flathead 1 . A bolt or screw having a flat top
surface and a conical bearing surface. 2. A rivet
head that has been flattened.

flat paint A paint which dries either without

gloss or with very low gloss.
flat paintbrush See flat wall brush.

flat piece A particle of aggregate in which the
ratio of the width to thickness of its circumscrib-
ing rectangular prism is greater than a specified
value. Also see elongated piece.

flat plate A flat concrete slab having no col-
umn capitals or drop panels.

flat pointing, flat-joint pointing The sim-
plest form of pointing. Mortar in the joints of
brickwork is finished flush with the face of the
masonry with a flat trowel.

flat rolled Descriptive of a product (such as a
steel plate, strip, or sheet) of a rolling mill which
is equipped with smooth-faced rolls, in contrast
to rolls used to manufacture special shapes.

flat roof A horizontal roof either having no
slope, or a slope sufficient only to effect drain-
age, its pitch being usually less than 10 degrees;
it may be surrounded by a parapet or it may
extend beyond the exterior walls.

flat-sawn Same as plain-sawn.

flat seam In sheet metal work, a seam between
adjacent metal sheets, formed by turning up
both edges, folding them over, and then flatten-
ing; the joint, so formed, usually is soldered.

-Head
twi^KI

flathead

flathead dormer Same as shed dormer.

flathead rivet A rivet which has the point
hammered flat instead of rounded.

flat joint Same as flush-cut joint.

flat-joint jointed pointing Flat-joint point-
ing in which the grooves are further embellished
by narrow grooves along their center lines, or by
grooves at top and bottom, next to the bricks.

flat keystone arch A flat arch with a keystone
at its center.

SOLDER

forming a flat seam

flat skylight A skylight which is essentially
horizontal; has only enough slope to allow rain-
water to run off.

flat slab A concrete slab which is reinforced in
two or more directions, usually without beams or
girders to transfer the loads to supporting members.

flat spot An imperfection on a glossy painted
surface; a spot lacking gloss, usually caused by a
porous spot on the undercoat.

flat spray sprinkler In a fire protection sys-
tem, a sprinkler providing a parabolic water dis-
tribution which directs 60 to 80 percent of the
total water flow initially in a downward direc-
tion toward the floor; some water is sprayed
toward the ceiling.

415

flatting

flatting l.Same as flat cutting; also see ripsaw-
ing. 2. Same as flatting down.

flatting agent A substance which lowers gloss
of paints or varnishes to which it is added.

flatting down, rubbing Rubbing abrasive
powder or similar material on a surface to lower
the gloss and make it more uniform.

flatting oil A thin solution which is added to
glossy paint or varnish so that a semigloss or
matte finish may be obtained.

flat truss Same as parallel-chord truss.

flat top truss Same as Howe truss.

flat varnish, matte varnish A varnish which
dries either without gloss or with a low gloss.

flat wall brush, flat paintbrush A paintbrush
usually 4 to 6 in. (10 to 15 cm) in width, with
long, stiff bristles, usually made of synthetic fiber.

flaunch Same as flanch.

fleaking Same as thatching.

fleche A spire, usually comparatively small and
slender, above the ridge of a roof, particularly
one rising from the intersection of the nave and
transept roofs of Gothic churches.

fleck A small spot, mark, or figure in wood, usu-
ally caused by wood rays, or other irregular
growth characteristics, e.g., natural deposits of
gummy matter.

fleet angle In hoisting gear, the maximum
angle between the rope (as it comes off the drum
on which it is wound) and a perpendicular to the
axis of the drum.

Flemish bond A brick pattern in which each
course consists of headers and stretchers that are
laid alternately; each header is centered with
respect to the stretchers above and below it.

Flemish bond

Flemish cross bond Similar to Flemish bond

but with two additional headers in place of a
stretcher at intervals.
Flemish diagonal bond A bond in which a
course of alternate headers and stretchers is

followed by a course of stretchers, resulting in

a diagonal pattern.
Flemish eaves Same as flared eaves.
Flemish gable A gable having a pediment

whose outline contains two or more curves on

each side of its apex.

Flemish gable

Flemish gambrel roof Same as Dutch gam-
brel roof.

Flemish garden-wall bond Similar to Flem-
ish bond but with three stretchers between each
header instead of a single stretcher.

Flemish garden-wall bond

fletton An English brick made from Oxford
clay; manufactured by the semi-dry-press
process; represents over 40% of current British
brick production.

416

flexible metallic hose

fleur»de-lys The French royal lily, conventional-
ized as an ornament in Late Gothic architecture.

fleuri cut A mottled effect obtained by cut-
ting stones parallel to their natural bedding
planes.

fleuron l.The small flower at the center of
each side of the Corinthian abacus. 2. Any small
flower-like ornament in general.

FLEURON

fleuron, 1

flexibility The property of a material that
allows it to bend without damage (and without
losing its strength) and then to return to its orig-
inal shape.

flexible cable See cable, 1 and cable, 2.

flexible conduit See flexible metal conduit,
flexible nonmetallic tubing, flexible metallic
hose, flexible seamless tubing.

flexible connector l.A nonmetallic airtight
connection in ductwork, between a fan and a
duct or between ducts, to prevent the transmis-
sion of vibration along the duct. 2. In a piping
system, a connector, usually fabricated of a com-
bination of metallic mesh and a nonmetallic
material; used to minimize the transmission of
vibration along the piping system (as between
pipes or between a pipe and a pump, etc.) or to
reduce pipe misalignment. 3. An electric con-
nection that permits the contraction, expan-
sion, or relative motion between connected
parts of rotating machinery.

flexible connector, 1

flexible coupling A coupling, used in rotating
machinery, having high transverse or torsional
compliance.

flexible drop-chute A heavy elastic or rub-
berized canvas collapsible tube which serves as a
drop chute.

flexible duct connector In an air-condition-
ing system, a short length of flexible non-porous
material that is inserted between metal duct-
work and a metal air diffuser (or air register);
prevents the transmission of vibration between
these components of the system.

flexible ductwork Round flexible ducts in an
air-conditioning system used to reduce the trans-
mission of vibration along the ductwork; used in
place of sheet-metal ductwork both to transfer
air from one location to another and to reduce
installation costs.

flexible joint A joint between two conduits,
ducts, or pipes that permits one of them to be
deflected or moved without significantly dis-
turbing the other.

flexible metal conduit A flexible raceway
which is circular in cross section, esp. constructed
for the pulling in or withdrawing of cables or wires,
after the conduit and its fittings are in place.

flexible metallic hose Hose made from a con-
tinuous coil of strip metal; embodies an interlocked

flexible metallic hose

417

flexible-metal roofing

construction with a packing wound continuously
into the grooves in the interlocked joint; suitable
for use with water, oil, and gases at low pressure.

flexible-metal roofing Roof coverings of flat
sheet metal such as aluminum, copper, or galva-
nized iron.

flexible-metal sheeting See sheet metal.

flexible mounting A flexible support be-
tween rotating machinery and the foundation or
slab on which it is mounted; used to reduce the
transmission of vibration from machinery to the
foundation or slab.

flexible nonmetallic tubing A mechanical
protection for electric conductors; consists of a
flexible tubing having a smooth interior and a
wall of nonconducting fibrous material.

flexible pipe connection Same as flexible
connector.

flexible seamless tubing A flexible metal
tubing made from seamless, welded, or soldered
tubing; commonly made from steel, bronze,
stainless steel, and a variety of alloys; not suscep-
tible to leakage; esp. used for gases under pres-
sure and volatile gases; sometimes enclosed
within a flexible braid.

flexible seamless tubing

flexural bond In prestressed concrete, the stress
between the concrete and the tendon which
results from the application of an external load.

flexural center See shear center.

flexural rigidity A measure of stiffness of a
structural member; the product of modulus of
elasticity and moment of inertia divided by the
length of the member.

flexural strength That property of a solid
which is an indication of its ability to withstand
bending.

flexure The bending of a member, as under a load.

FLG On drawings, abbr. for flooring.

flier, flyer l.Any of the steps in a straight
flight of stairs, each tread of which is of uniform
width (as distinguished from the treads in a
winding stair). 2. A flying shore.

flies, fly loft The space over a theater stage for
hanging scenery or other equipment by means of
movable rigging.

flight A continuous series of steps with no inter-
mediate landings.

flight header A horizontal structural member
used in stair construction, at a floor or platform
level, to support the end(s) of one or more
strings, 1.

flight rise The vertical distance between the
floors or platforms connected by a flight of stairs.

flight run Same as run, 3.

flint A dense, fine-grained stone; a form of silica;
naturally occurs in the form of nodules; usually
gray, brown, black, or otherwise dark in color, but
nodules and other chunks tend to weather white
or light shades from the surface inward. Broken
"flints," as the nodules are called, are used in cob-
ble size, either whole or split (knapped) in
mortared walls, esp. in England.

flint glass 1. A soda-lime-quartz glass having a
high transparency. 2. A glass that contains lead.

flitch 1. A portion sawn from a log and normally
manufactured into veneer or lumber. 2. Sheets of
veneer, stacked in sequence, as cut from the log. 3.
A thick timber cut with bark on one or more edges.
4. A board which forms part of a flitch beam.

flitch beam, flitch girder, sandwich beam
A beam built up of structural timbers which are
bolted together with a steel plate sandwiched
between them.

flitch beam

flitch plate The steel plate which is sand-
wiched between the timbers in a flitch beam.

float A flat tool with a handle on the back;
used on cement or plaster surfaces for smooth-
ing or for producing textured surfaces. Also
see angle float, bull float, carpet float, rotary
float.

float check A type of check valve; as water
flows into a atmospheric-type vacuum breaker,

418

float trap

float

the float check rises and seals against the air inlet
port, permitting water to flow through. When the
water is turned off, the float check falls, opening
the air inlet port, thereby preventing backflow.

float coat A finish coat of cement applied with
a float.

float-controlled valve See float valve.

floated coat, topping coat A plaster coat
which has been applied with a float, usually over
the scratch coat.

float finish A rather rough concrete or mortar
surface texture obtained by finishing with a
float; rougher than a trowel finish.

float glass 1. A glass plate, formed by pouring
molten glass continuously from an oven onto a
shallow bath of molten tin on which it floats,
thus spreading out and producing level parallel
surfaces on both sides of the glass. The surfaces
of the glass make no contact with rollers or other
surfaces until the molten glass has solidified.
2. See plate glass.

floating Smoothing newly applied mortar, plas-
ter, or concrete with a trowel or float.

floating brick A type of very lightweight brick.

floating coat Same as brown coat.

floating floor In sound-insulating building con-
struction, a floor slab (or floor assembly) which is

PLYWOOD
(TAPED JOINTSI

PREC0MPRE5SEO

INSULATION
3SARD

PRE COMPRESS ED

FLOOR INSULATION
BOARD

completely separated from (and mechanically iso-
lated from) the structural floor by a resilient
underlayment, such as fiberglass floor-isolation
board, or by resilient mounting devices; used to
isolate the vibration of machinery mounted on
the floating floor from the building structure.

floating foundation A reinforced concrete
slab used to support and distribute the concen-
trated load from columns in a soil having low
bearing capacity; also called a raft foundation or
mat foundation.

floating rule A long straightedge used as a float.

floating slab A reinforced concrete slab which
rests on vibration isolators or on a layer of resilient
material, as illustrated under floating floor.

floodwall A wall that is capable of protecting
an area from floodwater.

floating wood floor A floating floor consist-
ing of wood flooring floating on a resilient layer
of material which completely separates it from
the building structure.

float scaffold A scaffold hung from overhead
supports by ropes and consisting of a substan-
tial platform having diagonal bracing under-
neath, resting upon and securely fastened to two
parallel plank bearers at right angles to the span.

floatstone In bricklaying, a stone used to rub
curved work smooth and remove ax marks.

float switch An electric switch which is actu-
ated automatically when a float on the surface
of a liquid reaches a preset level.

High-water level

Round copper float
Low-water level

float switch

i a water tank

concrete floating floor construction of fiberglass
insulation board

float trap A mechanical buoyancy-operated
steam trap in which a ball float changes level as
the quantity of steam condensation in the trap

419

float valve

varies, thus controlling the discharge of steam
through the trap.

float valve, float-controlled valve A valve

which controls the flow of water; its opening or
closing depends on the position of a float which
rides on the surface of water in a tank, as in a
water closet.

flock spraying, flocking The creation of a
textured effect similar to suede or felt by blowing
fibers of cotton, silk, nylon, or other material
onto a tacky film of varnish.

flood coat 1. See flow coat. 2. In an aggregate-
surfaced, built-up roof, the top layer of bitumen,
which is poured on the surface.

flooding l.The stratification of different-
colored pigments in a paint film. 2. Introduc-
ing water, by gravity, into the backfill
surrounding a pipe in order to compact the
backfill. 3. A temporary condition of partial
or complete inundation of normally dry land
areas resulting from (a) the overflow of inland
or tidal waters, or (b) the unusual and rapid
accumulation of runoff of surface waters from
any source.

flood level In a plumbing fixture, the level at
which water begins to overflow the top or rim of
the fixture.

flood-level rim The edge of a plumbing fixture
or receptacle over which water would flow if it
were full.

f
[-

FLOOD LEVEL RIM

floodlight l.A projector type of luminaire;
designed for lighting a large area or an object to
a level of illumination which is considerably
greater than that of its surroundings. 2. In stage
lighting, a unit of one or more lamps in a metal
housing, usually nonfocusing and used to illumi-
nate a large area diffusely.

LAMP

WIDE DIFFUSE
BEAM

flood-level rim

floodlight

flood plain Any land area susceptible of being
inundated by water from any source.

floor 1 . In a room, the surface on which one walks.
2. A division between one story and another; one
story of a building. Also see blind floor, counter-
floor, earth floor, finish floor, ground floor, lowest
floor, threshold floor, underfloor, upper floor.

floor anchor Same as base anchor.

floor arch l.A flat concrete slab supported by
beams. 2. An arch which has a flat extrados.

floor area See gross floor area; net floor area.

floor area ratio The ratio of the total floor
area of a building (excluding areas such as
mechanical rooms or the areas of floors used
exclusively for mechanical equipment) to the
area of the lot on which the building is built.

floor batten A batten which is fixed to a con-
crete subfloor and to which flooring is nailed.

floor beam A beam supporting the floor of a
building or the deck of a bridge.

floorboard One of the boards or planks used as
the finish floor, forming the walking surface of
the room.

floor box A metal outlet box providing for out-
lets from conduits concealed in the floor.

420

floor joint

floor brick Smooth, dense brick, highly resis-
tant to abrasion; used for finished floor surfaces.

floor chisel A steel chisel having a broad blade
and a long shank; esp. used for ripping up floor
boards.

floor clamp, floor cramp, floor dog A
clamp used to force floorboards together while
nailing them to the joists.

floor clearance The distance between the
bottom of a door and the finish floor or saddle.

floor clip Same as sleeper clip.

floor closer A door-closing device which is
installed in a recess in the floor below the door
to regulate the opening and closing swing of the
door.

floor closer

floorcloth A heavy canvas used as carpeting;

may be decorated.
floor decking Same as decking, 1.
floor dog Same as floor clamp.

floor drain A fixture providing an opening in a
floor to drain water into a plumbing system; in
homes, usually fitted with a deep seal trap.

floor framing Framing consisting of common
floor joists, cross bridging, solid bridging, and
other members which provide support for flooring.

floor furnace See floor-type heater.

floor furring Wood furring strips fixed to a
subfloor to provide clearance for piping or con-
duit laid directly on the subfloor.

floor guide A groove in a floor or surface-
mounted hardware on the floor, used to guide a
sliding door.

floor hanger A stirrup, 2.

floor hatch A hinged panel unit which pro-
vides access through a floor.

floor hinge Same as floor closer.

floor hole According to OSHA: any opening
measuring less than 12 in. (30.5 cm) but more
than 1 in. (2.5 cm) in its least dimension in any
floor, roof, or platform through which materials
but not persons may fall, such as a belt hold, pipe
opening, or slot opening.

flooring Any material used as the finish surface
of a floor, such as boards, bricks, planks, or tile.

flooring block One of many closely-fitting
pieces of wood used in laying a floor; often the
wood pieces are of different colors, forming a
decorative pattern.

flooring brick A dense, hard brick that is espe-
cially resistant to heavy surface wear.

flooring cement Same as Keene's cement.

flooring nail A steel nail with a mechanically
deformed shank, often helically threaded, hav-
ing a countersunk or casing head and a blunt
diamond point.

Sadinunt
bucket

typical floor drains

floor fill A filler between the structural floor

slab and the finish floor.
floor flange Same as escutcheon, 2.

flooring nail

flooring saw A handsaw which tapers to a
point, with teeth on its upper edge as well as
along the bottom; used for cutting holes in wood
floors.

flooring strips See strip flooring.

flooring tiling See floor tile.

flooring underlayment See underlayment.

floor joint A joint between the sides of boards
or planks which are continuous from end to end.

421

floor joist

floor joist Any joist which carries a floor.

floor light A window in the floor which trans-
mits light to the room below it; of heavy glass,
designed to support the normal floor loads.

floor line A line, or series of short lines, as on a
wall, establishing the level of the finish floor.

floor lining paper See building paper.

floor load The live load for which a floor of a
building has been designed, and which may be
applied safely; usually expressed as a uniformly
distributed load, except where there are concen-
trations of heavy machinery.

floor molding See base shoe.

floor opening According to OSHA: an open-
ing measuring 12 in. (30.5 cm) or more in its
least dimension in any floor, roof, or platform,
through which persons may fall.

floor outlet Same as floor receptacle.

floor panel A prefabricated unit consisting of
flooring, subflooring, and reinforcing joists; sup-
ported by columns, walls, or beams.

floor pit A recess below a floor which provides
access to parts beneath a machine, as an elevator
pit.

floor plan A drawing; a horizontal section taken
above a floor to show, diagrammatically, the
enclosing walls of a building, its doors and win-
dows, and the arrangement of its interior spaces.

floor plate 1. A flat metal plate which is set in
a floor; usually provided with slots into which
equipment can be fastened. 2. A steel plate hav-
ing a raised pattern which provides a nonslip
wearing surface.

floor plug See floor receptacle.

floor pocket A stage pocket set into a theater
stage floor.

floor receptacle In an electric circuit, a recep-
tacle which is mounted in an outlet box, set
flush with the floor.

floor receptacle

floor register A register which is set flush with
a floor.

floor sealer A sealer, 1, in liquid form when
applied, which seals the pores of a floor surface
such as cement or wood.

floor slab A structural slab serving as a floor;
usually of reinforced concrete. Also see slab, 1.

floor sleeve A hollow metal tube which pene-
trates, and is set into, a floor.

floor socket outlet Same as floor receptacle.

floor stilt A device attached to a doorframe
jamb to hold the bottom of the frame above the
finished floor level.

floor stop A doorstop which is set into the floor.

floor strutting Same as bridging.

floor surfacing The grinding or sanding of a
floor surface to provide a clean, level surface.

floor system 1 . The system of structural com-
ponents which separate the stories of a building.
2. In a building, the structural floor assembly
between the beams and girders.

floor tile 1. A resilient material such as asphalt,
vinyl-asbestos, rubber, vinyl, cork, or linoleum
manufactured in modular units; laid on a floor as
the finish flooring. 2. Structural tile units for
floor and roof slab construction.

floor trap In a burglar alarm system, a device
which includes a thread or very thin electrical
conductor which extends across a floor space
that activates an alarm when moved or broken.

floor-type heater, floor furnace A heater
consisting of a burner, air-heating radiator, and
valves which are suspended from a floor (usually in
a single-story house) beneath a grille which is
flush with the floor; warm air rises from the center
of the grille, and return air descends around its
perimeter.

floor varnish, finishing varnish A tough,
durable high-gloss, wear-resistant varnish used
on wood flooring.

floor ventilation The passage of air, between
openings in a foundation wall, beneath a building.

Florentine arch A semicircular arch having
its extrados struck from a higher point than its
intrados so that the length of the voussoirs is
longer nearer the top of the arch.

Florentine lily Same as giglio.

Florentine mosaic A kind of mosaic made
with precious and semiprecious stones, inlaid in
a surface of white or black marble or similar

422

flowing tracery

material, generally displaying elaborate flower
patterns and the like.

floriated, floreated Decorated with floral pat-
terns.

floriated Romanesque capital

florid Highly ornate; extremely rich to the
point of overdecoration.

flounder house A two- or three-story house
that is one room deep and several rooms wide; its
roof is in the shape of an inclined plane that runs
the full length of the house, giving it the appear-
ance of one-half of a gable roof.

flounder roof Same as shed roof.

flow 1. See cold flow. 2. A measure of the consis-
tency of freshly mixed concrete, mortar, or cement
paste in terms of the increase in diameter of a
molded truncated-cone specimen after jigging a
specified number of times. 3. That characteristic
of a paint which enables it to form a uniform,
smooth surface without showing brush marks or
other evidence of the method of application.

flow chart A graphical representation of the
steps taken in defining, analyzing, and solving a
problem or undertaking an activity.

flow coat A coating obtained by completely
drenching an object with streams of paint and
allowing the excess to drain off. Also called a
flood coat.

How cone A device for measuring grout consis-
tency; after a predetermined volume of grout is

permitted to flow through an orifice of known
size, the time of efflux (called the flow factor) is
an indication of the consistency.

flow-control device In a controlled-flow roof
drainage system, a device that controls the rate at
which rainwater is permitted to drain off a roof.

flow factor See flow cone.

Flowing style An old term for the later phases
of the English Decorated and the French Flam-
boyant styles of Gothic architecture; a term
derived from the flowing quality of the tracery.

flowing tracery, curvilinear tracery, undu-
lating tracery Tracery in which continuous
curvilinear patterns (largely ogees) dominate. A
characteristic feature of the Decorated and Flam-
boyant styles.

flowing tracery: Little St. Mary's, Cambridge (c. 1350)

423

flow pressure

flow pressure The pressure in the water-supply
pipe near a faucet or water outlet while the faucet
or water outlet is wide open and water is flowing.

flow promoter A substance added to a coating
to enhance brushability, flow, and leveling.

flow slide The failure of a sloped bank of soil in
which the soil movement does not take place
along a well-defined surface of sliding.

flow test A standardized laboratory test to deter-
mine flow, 2.

flow trough An open channel used to convey
concrete by gravity flow from a receiving hopper
or truck mixer to the point of placement.

flown Said of scenery that is suspended from the
gridiron of a theater, in contrast to scenery that
stands on the stage.

flue An incombustible, heat-resistant enclosed
passage in a chimney to control and carry away
products of combustion from a fireplace to the
outside air. Often, several fireplaces within a home
are connected to a single large flue, but it is also
common to carry up one flue for each fireplace.

flue block See chimney block.

flue effect See chimney effect.

flue gathering See gathering.

flue grouping The inclusion of several flues in
one chimney or stack to minimize the number of
vertical shafts up through a building.

flue lining, chimney lining In a chimney flue,
a lining consisting of special heat-resistant fire-
brick or other fireclay units, heat-resistant glass
units, or special concrete block; used to prevent
fire, smoke, and gases in the flue from spreading to
surroundings.

-FLUE LINING

-=E

CONCRETE
CAP

jl:

flue lining

flue pipe An airtight conduit which conveys
the products of combustion from a furnace to the
atmosphere or to a chimney stack.

flue surface In boiler flues, the total surface area
which is exposed to high temperature or hot gases.

flue terminal Same as chimney cap.

flueway The clear space (free open area) for
the passage of flue gases within a chimney.

fluid-applied roofing See asphalt-prepared
roofing.

fluid-filled column A hollow structural-steel
column which is filled with liquid; if exposed to
flame, the liquid absorbs heat and rises within the
closed-loop system, being replaced with cooler
fluid.

fluidifier An admixture employed in grout to
decrease the flow factor (time of efflux from a stan-
dard orifice) without changing its water content.

fluidity The quality of being fluid, or capable of
flowing; that quality of a body which renders it
incapable of resisting tangential stresses.

fluing Expanding or splaying, as the splayed
jambs of a window.

flume An open channel for carrying water; usu-
ally constructed of metal, concrete, or wood.

FLUOR On drawings, abbr. for "fluorescent."
fluorescence The emission of visible light
from a substance (such as a phosphor) as the
result of, and during, the absorption of radiation
of shorter wavelengths.

fluorescent lamp A low-pressure electric-
discharge lamp; ultraviolet-light radiation is
generated by the passage of an arc through
mercury vapor; the inner surface of the lamp
tube is coated with a phosphor which absorbs
the ultraviolet and converts some of it into vis-
ible light.

LAMPHOLDER

BASE PINS

BALLAST INSIDE
CHANNEL

fluorescent lamp

424

flushing tank

fluorescent lighting fixture A luminaire, usu-
ally complete with fluorescent lamps, sockets, bal-
last, reflector, and a louver or diffusing medium.

fluorescent-mercury lamp See phosphor
mercury- vapor lamp.

fluorescent paint See luminous paint.

fluorescent pigments Pigments of excep-
tional brilliance which absorb ultraviolet radi-
ant energy and reemit it as visible light.

fluorescent reflector lamp A fluorescent
lamp having reflective powder between the
phosphor and the tube wall over part of the cir-
cumference; this directs a larger percentage of
the light flux to one side.

fluorescent snaking The apparent swirling
and twisting of the arc in a fluorescent lamp; a
common phenomenon in a new lamp until it has
been turned on and off a few times.

fluorescent strip A fluorescent luminaire in
which the lamp(s) are mounted on a wiring
channel containing the ballast and lamp sock-
ets, usually without light reflectors or lenses.

fluorescent tube See fluorescent lamp.

fluorescent U-lamp A tubular fluorescent
lamp whose bulb has a 180° bend at the center,
forming a U-shaped lamp.

fluosilicate A salt, usually of magnesium or zinc,
used on concrete as a surface-hardening agent.

flush Having the surface or face even or level
with the adjacent surface.

flushed Said of a stone having damaged arrises
as a result of improper handling.

flush bead See quirk bead, 2.

flush bolt A door bolt so designed that when
applied it is flush with the face or edge of the door.

flush bolt backset The distance from the ver-
tical center line of the leading edge of a door to
the center line of the bolt.

flush bushing In plumbing, a bushing which
has no shoulder; fits flush into the fitting with
which it is connected.

flush chimney An interior chimney whose
outer surface is flush with an exterior wall.

flush-cup pull A door pull which is mortised
flush into a door, having a recess to receive fin-
gers to actuate the slide of the door.

flush-cut joint, flush joint In brickwork, a
masonry joint in which an excess of mortar is
applied; then a trowel is held flat against the
brick surface and moved along the surface, so as
to cut away the excess mortar. The resulting
joint is flush with the wall, and is usually not
watertight as a result of small hairline cracks
produced by the cutting action as the trowel
removes the excess mortar.

flush bolt

flush-cut joint

flush door A smooth-surfaced door having
faces which are plane and which conceal its rails
and stiles or other structure.

flush eaves Eaves where there is no roof pro-
jection requiring a plancier piece; instead, the
eaves fascia is against the wall surface and is
attached directly to it.

flush girt A girt that runs parallel to joists and
is placed at the same level as the joists.

flush glazing Glazing in which glass is set in a
recess in a frame; stops (if any are used) also are
recessed; the glazing is flush with the frame jamb
surface.

flush-head rivet A rivet having a countersunk
head.

flushing cistern See flush tank.

flushing tank See flush tank.

425

flushing-type floor drain

flushing-type floor drain A floor drain,
equipped with an integral water supply that
enables the drain receptor and trap to be flushed.

flushing valve See flush valve.

flush molding Molding whose surface is in the
same plane as that of the wood member or
assembly to which it is applied.

flushometer, flushometer valve A valve
designed to supply a fixed quantity of water for
flushing purposes; is actuated by direct water pres-
sure, without the use of a cistern or flush tank.

Valve body

Vacuum breaker

flushometer

flush panel A panel whose surface is in the
same plane as the face of the surrounding frame.

flush paneled door A paneled door in which,
on one or both faces, the panels are finished
flush with the rails and stiles.

flush pipe A straight pipe which conveys flush-
ing water from the source of supply to a water
closet.

flush plate A metal or plastic cover for a flush
wiring device in a wiring box, providing a neat
covering for an outlet or switch; supported by

screws in tapped holes in the metal housing for the
device; holes in the plate accommodate handles
for switches or plugs for flush outlet receptacles.

flush pointing In brickwork, the troweling of
mortar into joints by scraping a trowel against
the wall surface to remove excess mortar.

flush ring A flush door pull which is mortised into
a door; has a ring pull that folds flat into the cup of
the pull when not in use.

dR3

flush ring

flush siding A wood exterior covering on the
walls of a colonial New England house of wood-
frame construction; commonly made of pine
boards that have been sawn and planed smooth.
These boards, applied horizontally, are usually
wider than ordinary clapboard and are nailed flat
against the studs; the upper edge is often beveled
and may be overlapped by the board above.

flush soffit The smooth underside in a flight of
spandrel steps.

flush sprinkler A fire sprinkler (head) in
which all or part of the body is mounted above
the lower plane of the ceiling.

flush switch In electric wiring, a switch which
is mounted in a flush wall box so that only its
front face is visible.

flush tank A tank which holds a supply of water
for flushing of one or more plumbing fixtures.

flush plate

flush tank

426

flying form

flush tracery Said of tracery that is flush with
the face of the wall in which it is set.

flush valve l.A special valve located at the
bottom of the tank of a water closet, or the like;
provides the discharge through which the fixture
is flushed. 2. A diaphragm-type flushometer.

flush wall box A wall box which houses an
electric device, embedded in a partition, ceiling,
or floor so that the face is flush with the surface.

flush water See wash water.

flushwork (Brit.) 1. Masonry which contrasts
smooth ashlar with knapped flint; the split side
is set flush with the wall face. 2. Masonry of two
different types, such as flint and dressed stone,
laid so as to produce a pattern whose finish is
essentially in the same plane.

flute A groove or channel, esp. one of many
such parallel grooves, usually semicircular or
semielliptical in section; used decoratively, as
along the shaft of a column.

fluted rolled glass Flat sheet glass, one surface
of which is impressed with a pattern of narrow
parallel flutes.

fluted 'work A surface finish that consists of a
series of concave grooves, as opposed to cor-
duroy work which consists of a series of narrow
convex reeds.

fluting A series of flutes, as on a column.

innnpr

fluting

flutter echo A rapid succession of echoes
caused by the reflection of sound back and forth
between two parallel walls; initiated by a single,
sharp pulse of sound.

flux l.A fusible substance used in oxygen cut-
ting, welding, brazing, or soldering operations;
assists in the fusion of metals and the prevention
of surface oxidation. 2. A bituminous material,

generally liquid, used for softening other bitumi-
nous materials.

flux-cored arc welding Any one of a group
of welding processes in which coalescence is pro-
duced by the heating of an arc; the arc is
between the work being welded and a continu-
ous filler metal electrode.

flux oil A thick, relatively nonvolatile fraction
of petroleum used as flux, 2.

fly ash The finely divided residue resulting from
the combustion of ground or powdered coal,
transported from the firebox through the boiler
by flue gases.

fly ash concrete Concrete that contains fly
ash as the aggregate.

fly bridge On a theater stage, a platform for
supporting lights or other equipment which is
hung by means of rigging.

fly curtain A theater curtain which can be
raised into the flies.

flyer See flier.

fly floor, fly gallery In a theater, a narrow
balcony above the stage floor, usually on both
sides of the stage, sometimes with an intercon-
nection across the back wall.

fly gallery See fly floor.

flying bond Same as monk bond.

flying buttress A characteristic feature of Gothic
construction, in which the lateral thrusts of a roof
or vault are taken up by a straight bar of masonry,
usually sloping, carried on an arch, and a solid pier
or buttress sufficient to receive the thrust.

flying buttress: A

flying facade See false front.
flying form A large prefabricated unit of form-
work designed for reuse.

427

flying formwork

flying formwork Slabs of formwork so large
that they must be moved by crane.

flying gallery See fly floor.

flying gutter Same as a Dutch kick.

flying rib A rib, 2 that is free of its masonry
shell.

flying scaffold Suspended staging which is
hung from outrigger beams at the top of a struc-
ture by means of ropes or cables.

flying shelf A mantel or shelf above the fire-
place opening which is cantilevered from the
chimney construction.

flying shore A timber which provides tempo-
rary support between two walls; a horizontal sup-
porting shore.

fly ladder A ladder, at the side or rear of a the-
ater stage, providing access to the fly floor.

fly line In a theater stagehouse, a rope or wire line
used to hang scenery or equipment from the flies.

fly loft See flies.

fly rafter A rafter in the projecting portion of a
gabled roof.

RIDGE
RAFTER

TOP PLATES

fly rafter

fly rail, pinrail, working rail In a theater
stagehouse, a railing on the stage side of the fly
floor; used for tying off lines when scenery is
hauled into the flies.

flyscreen Same as screen, 2.

fly screen door Same as screen door.

fly stair A stairway from the stage of a theater
to the fly floor and above.

fly wire screening Same as insect wire screen-
ing.

FMT Abbr. for "flush metal threshold."

foam concrete See foamed concrete.

foam core The rigid foam material that is used
in sandwich panel construction.

foamed adhesive An adhesive, the density of
which has been decreased substantially by the
presence of numerous gaseous cells dispersed
throughout its mass.

foamed blast-furnace slag See expanded
blast-furnace slag.

foamed concrete, foam concrete A very
light, cellular concrete; made by the addition of
a prepared foam or by the generation of gas
within the unhardened mixture.

foamed-in-place insulation A plastic foam;
prepared by mixing the ingredients with a foam-
ing agent immediately before placement, either
by pouring the material into enclosed cavities or
by application with a spray gun; used for thermal
insulation.

foamed-in-situ plastics See foamed-in-place
insulation.

foamed plastic, plastic foam l.A plastic
expanded chemically, mechanically, or thermally,
to form a lightweight closed-cell structure; used as
thermal insulation. Also see chemically foamed
plastic. 2. A resin in a sponge form, either flexible
or rigid, with cells that are either closed or inter-
connected.

foamed polystyrene A foamed plastic weigh-
ing about 1 lb per cu ft (0.016 gm per cu cm);
grease-resistant, low in cost, high in thermal
insulation value.

foamed slag See expanded blast-furnace slag.

foam fire-extinguishing system A fire-
extinguishing system employing a special means
to discharge foam, made from concentrates, over
a protected area.

foam glass, cellular glass, expanded glass
A thermal insulation made by foaming softened
glass to produce many sealed bubbles; has a
closed-cell structure. Molded into board and
blocks, usually with a density of about 9 to 10 lb
per cu ft (14-4 to 16 kg per cu m).

foaming agent A substance that is added to a
material in the plastic state to generate gases
within the material and cause it to assume a
lightweight, foamy structure; used with concrete
mixtures, gypsum, plastics, rubber, etc.

foam rubber Same as sponge rubber.

FOB Abbr. for "free on board."

fodder house A small shedlike structure for
storing coarse food for livestock.

428

folding partition

fog curing The curing of concrete products in
a room having very high humidity (achieved
by the atomization of water). Also see moist
room.

fogon In Spanish Colonial architecture, a cook-
ing stove or fireplace with a chimney; usually
constructed of adobe brick and finished with
adobe plaster. It was commonly located across
one corner of a room.

fog room Same as moist room.

fog sealed Said of a surface which has received
a light surface treatment of asphalt, without a
mineral cover.

FOHC In the lumber industry, abbr. for "free of
heart centers."

foil 1 . In tracery, any of several rounded lobes
that meet each other in points called cusps;
widely used in Gothic architecture, Gothic
Revival architecture, and Collegiate Gothic; see
trefoil (three lobes), quatrefoil (four lobes),
cinquefoil (five lobes), and multifoil (usually
greater than five lobes). 2. A metallic substance
formed into very thin sheets, usually by a rolling
process.

foils

foil arch An arch with cusps or foils on its
intrados.

foil-backed gypsum board, insulating
plaster»board Gypsum board having an alu-
minum foil on one of its surfaces providing a
vapor-resistant membrane and increased resis-
tance to heat flow.

foil-backed gypsum lath A plain gypsum
lath, the back surface of which is covered with a
continuous sheet of aluminum foil.

foil-backed gypsum wallboard A gypsum
wallboard, the back surface of which is covered
with a continuous sheet of aluminum foil.

foiled Decorated with foils.
foiled arch Same as cusped arch.

FOK Abbr. for "free of knots."

folded-plate construction, hipped-plate
construction Construction consisting of
thin, flat elements of concrete, steel, timber, etc.,
which are connected rigidly at angles with each
other (similar to accordion folds), forming a stiff
cross section which is capable of carrying a load
over a long span.

folding casement l.One of a pair of case-
ments, 1, with rabbeted meeting stiles which is
hung in a single frame having no mullion. 2.
One of two or more casements, 1 , which are
hinged together so that they can open and fold
in a confined space.

folding casement

folding door 1 . One of two or more doors
which are hinged together so that they can open
and fold in a confined space. 2. One of a pair of
doors hung from the jambs of a single opening.
Also see accordion door, multifolding door.

folding partition A movable door or parti-
tion comprised of a number of individual sec-
tions that are hinged and folded against each
other, but can be pulled open to form a contin-
uous vertical surface that divides a large space
into two smaller ones. Compare with falling

429

folding rule

wainscot; also see accordion partition, operable
partition, and sliding door.
folding rule A rule which is jointed at fixed
intervals for convenience in carrying.

folding rule

folding shutter See boxing shutter.

folding stair A disappearing stair.

folding wall An operable partition. Also see

accordion partition.
foliage capital A foliated, 2 capital.
foliated 1. Adorned with foils, as on tracery. 2.

Decorated with conventionalized leafage, often

applied to capitals or moldings.

foliated, 1: arches

foliated, 2: capital

foliated arch An arch having foils; a foil arch.

foliated joint A joint between two boards
made by overlapping two rabbeted edges, so as to

form a continuous surface on each face; a form of
joggle.

foliation l.The cusps or foils with which the
divisions of a Gothic window are ornamented.
2. Leaf-like decoration.

Folk architecture An imprecise term for
architecture intended to provide only basic
shelter suitable for the surrounding terrain and
climate, with no pretense of following current
styles of architecture. Such houses were built
using local materials and available tools, often
by the people who planned to live in them.

Folk Victorian architecture Same as Gin-
gerbread Folk architecture.

follow current The current that flows through
a surge arrester to ground, following the passage
of discharge current.

follow spot A theater spotlight used to follow a
performer on the stage.

folly, eye-catcher A functionally useless struc-
ture, often a fake ruin, sometimes built in a land-
scaped park to highlight a view.

fonar In early Russian architecture, a type of
lantern consisting of a cupola having many small
windows.

fons A fountain made by covering and decorat-
ing a natural spring with a structure or sculpture,
or by employing a jet of water that plays into an
artificial basin.

font A basin, usually of stone, which holds the
water for baptism.

food display counter A unit for the display
of food, esp. prepared food; usually temperature-
controlled.

food tray rail One of several rails, forming a
continuous shelf, installed at the front of food
dispensing units, as in a cafeteria.

food waste disposer Same as waste-disposal
unit.

foot base A molding above a plinth.

foot block A mat of concrete, steel, or timbers
used to distribute the load of a post or shore on
the soil that supports it.

foot bolt A bolt which is fixed at the bottom of
a door and can be operated by foot; usually when
the door is unbolted, the bolt head is held up by
a spring.

footbridge, pedestrian bridge A narrow
bridge designed to carry pedestrians only.

430

footstall

foot bolt

footing stop A board, temporarily inserted in a
concrete form as a stop for concrete at the end of
a day.

footlambert 1 . A unit of luminance equal to
1/n candela per sq ft. 2. The uniform luminance
of a perfectly diffusing surface emitting or
reflecting light at a rate of 1 lumen per sq ft.

footlight One of a row of lights set in a trough,
in a theater stage floor, which runs across the
width of the stage in front of the curtain.

footcandle A unit of illuminance in US Cus-
tomary units; equal to 1 lumen per square foot;
equals 10.76 lux.

footcandle meter Same as illumination meter.

foot cut See seat cut.

footer Same as footing.

footing That portion of the foundation of a struc-
ture which transmits loads directly to the soil; may
be the widened part of a wall or column, the
spreading courses under a foundation wall, a foun-
dation of a column, etc.; used to spread the load
over a greater area to prevent or reduce settling.

footing

footing beam Same as tie beam, 2.

footing course One of the courses of masonry at
the foot of a wall, broader than the courses above.

footing piece In staging, one of the horizontal
transverse members which support the platform.

footing stone A broad flat stone used as the
base or bottom course of a wall.

- - <•(.;<?)•

footlights

footlight spot A spotlight small enough to be
mounted in the footlights.

foot-meter rod A stadia rod, marked in feet and
tenths on one side and meters and hundredths on
the other side; used to determine distances and
elevations in one unit of measurement and to
check them by readings in the other system.

footpace 1 . A dais . 2 . A halfpace.

footpath A British term for sidewalk.

footpiece In a heating, ventilating, or air-con-
ditioning system, a piece of ductwork which pro-
vides a change in direction of air flow.

footplate 1 . In wood-frame construction, a tim-
ber used to distribute concentrated loads, as a
plate beneath a row of studs. 2. A hammer beam.

footprint The area on a plane directly beneath
a structure (or piece of equipment), that has the
same perimeter as the structure (or piece of
equipment).

foot run 1 . Same as board measure. 2. A foot of
length of any material.

foot scraper Same as boot scraper.

foot scraper

footstall l.The plinth or base of a pillar or
pier, usually having a distinctive architectural

431

footstone

treatment. 2. A pedestal which supports a pillar,
statue, etc.
footstone A kneeler, 1 ; a gable springer.

footway 1. A pedestrian walk or footpath. 2. A
sidewalk.

force account A term used when work, 1 is
ordered to be done without prior agreement as to
lump sum or unit price cost thereof and is to be
billed for at cost of labor, materials and equipment,
insurance, taxes, etc., plus an agreed percentage
for overhead and profit.

force cup Same as plumber's friend.

forced»air furnace A warm-air furnace equipped
with a blower to circulate the air through the
furnace and ductwork.

forced-air heating system A conventional
heat distribution system in which heat is circu-
lated by means of a blower (fan).

forced circulation Circulation of air, water,
etc., by mechanical means, such as a fan or
pump.

forced-circulation register A register for use

with a duct system conveying air under pressure;
permits the control of the discharged air in two
or more directions simultaneously.

forced-circulation boiler A boiler that uses
a mechanical pump to circulate water flowing
through the boiler's water tubes.

forced convection Heat transfer resulting
from the forced circulation of air, water, etc., as
by a fan, jet, or pump.

forced draft In a furnace, a draft of air which is
mixed with fuel before being fed into the com-
bustion chamber.

forced-draft boiler A boiler having a power-
operated fan which furnishes the burner and
boiler with air, and also forces the products of
combustion out through the chimney.

forced-draft fan A blower (fan) that creates a
positive pressure, forcing air into a combustion
chamber.

forced-draft water-cooling tower A water-
cooling tower having one or more fans located
in the air stream entering the tower.

forced drying A process for speeding up the
drying of paint, using a moderate heat, up to
150°F (65°C).

forced fit The joining of two parts, members,
etc., without the use of fasteners, by forcing the
two together.

forced ventilation The circulation of air by a
fan or blower.

forebay An integral part of a structure's upper
story that significantly overhangs the story
below; see forebay barn.

forebay barn A barn, often on a hillside, hav-
ing a forebay (usually on its downhill side) that
may be supported by a series of heavy posts or
pillars.

forebuilding An outer defense work of a castle
that was attached to a keep, protecting the stair-
way and entrance.

fore choir Same as antechoir.

forechurch A consecrated extension in front
of a larger church.

foreclosure The depriving of the right to a
property by legal transfer of title, esp. because of
failure to maintain mortgage payments.

foreclosure sale The optional right of the
mortgagee to resort to the sale of the mortgaged
property in the event of default in mortgage pay-
ments, and to apply the net proceeds realized
from its disposition to the unpaid debt.

forecourt A court forming an entrance plaza for
a single building or several buildings in a group.

forend British term for lock front.

fore plane A carpenter's plane, intermediate
in length, used between a jack plane and a
jointer, 4.

forestage 1. That part of a theater stage which
is on the audience side of the proscenium or
stage curtain. 2. See apron, 8.

foreyard An exterior court in front of a building.

forging A metal part, worked to a predeter-
mined shape by one or more of such processes as
hammering, upsetting, pressing, or rolling.

foris One of the two leaves of a door to a sacred
Classical edifice; often used in the plural
(fores).

fork-and-tongue joint A mortise-and-tenon
joint used to join timber rafters at the peak of a
roof.

forklift truck A power-operated vehicle hav-
ing heavy steel prongs which can be moved in
position under a load on a pallet, 2 and then

432

form nail

forklift truck

raised; esp. used in construction for moving
material around a job site.
form Temporary boarding, sheeting, or pans of
plywood, molded fiberglass, etc.; used to give
desired shape to poured concrete, or the like.

YOKE

form for

a concrete column

formaldehyde, methylene oxide A color-
less, pungent, volatile liquid, readily soluble in
water, widely used in the manufacture of plastics
and resins and as a disinfectant.

formal garden A garden whose plantings,
walks, pools, fountains, etc., follow a definite, rec-
ognizable plan, frequently symmetrical, emphasiz-
ing geometrical forms.

form anchor A device used to secure form-
work to previously placed concrete of adequate
strength.

format An AIA standardized arrangement of
the contents of the project manual, including
bidding information, contract forms, conditions
of the contract, and specifications (which are
subdivided into the sixteen divisions illustrated
under contract documents).

formation level Same as grade level.

form board, form liner, form lumber A
board or a sheet of wood used in formwork.

form coating A liquid coating applied to con-
crete formwork to promote ease of release of the
form from the concrete.

form deck Sheet metal which has been rolled
into parallel ridges and furrowed to provide addi-
tional mechanical strength; may serve as form-
work for reinforced concrete decking, 2.

formed plywood Curved plywood; manufac-
tured by being pressed between rigid forming dies.

formeret, wall rib One of the ribs against the
walls in a ceiling vaulted with ribs.

form hanger A hanger used as a support for
formwork which is hung from a structural frame-
work.

Formica A proprietary name for a durable sheet
of tough laminated plastic.

forming A process of shaping metal by
mechanical action other than machining, forg-
ing, or casting.

form insulation Thermal insulation which is
applied to the outside of concrete forms between
studs and over the top; used in sufficient thick-
ness, with an airtight seal, to retain the heat of
hydration so that the concrete is maintained at
the required temperature for proper setting in
cold weather.

form lining A lining on the concrete-face side of
formwork either: (a) to absorb water from the con-
crete, (b) to impart a patterned finish or smooth
finish to the concrete surface, or (c) to apply a set-
retarding chemical to the formed surface.

form nail See double-headed nail.

433

form oil

form oil An oil which is applied to the interior
surfaces of concrete formwork so as to promote a
clean break when the forms are removed.

form of agreement A document setting forth
in printed form the general provisions of an
agreement, 3, with spaces provided for insertion
of relevant data.

form of contract See conditions of the con-
tract.

form»pieces A medieval term for tracery.

form pressure In concrete construction, the
lateral pressure which acts on the vertical or
inclined surfaces of the formwork as a result of
the fluid-like behavior of the unhardened con-
crete within the formwork.

form release agent See release agent.

form scabbing The removal of the surface of
concrete as a result of the lack of a clean break
when the forms are removed; some of the con-
crete adheres to the form and is pulled away.

form spreader Same as spreader, 2.

form stop In concrete formwork, a temporary

wood piece used to limit the flow of concrete at

the end of a day's work.

form stripping agent Same as release agent.

form tie Any tie, in tension, which is used to
prevent concrete forms from spreading as a result
of fluid pressure of freshly placed, unhardened
concrete.

formwork A temporary construction to con-
tain wet concrete in the required shape while it
is cast and setting.

formwork nail A double-headed nail.

forniciform In the shape of a vaulted roof or
ceiling.

fornix In ancient Roman construction, a
vaulted surface.

Forstner bit A bit used for drilling blind holes
in wood.

fort A defensive work, exclusively military in
nature, that is strengthened for protection
against enemy attack and commonly incorpo-
rates a series of bastions (i.e., projections from
the outer wall of the fort) to defend the adjacent
perimeter; usually occupied by troops. See bas-
tion, battlement, breastwork, casemate, embra-
sure, loophole, rampart.

fortalice, fortilage A term used in the Middle
Ages chiefly for the word fort; since then, occa-
sionally used for a relatively small fort.

fortress 1 . A fortification of massive scale, gen-
erally of monumental character and sometimes
including an urban core; also called stronghold.
2. A protected place of refuge.

45° pipe lateral A pipe fitting similar to a pipe
tee except that the side opening is at a 45° angle.

forum A Roman public square surrounded by
monumental buildings, usually including a basil-
ica and a temple; the center of civic life. A forum
sometimes was purely commercial in aspect.

forum of Trajan, Rome, circa 110 A. D.

forward-curved fan A fan having forward-
curved blades; used primarily for HVAC appli-
cations where high-volume flow rates and low-
pressure characteristics are required.

foss A moat or ditch.

fosse A ditch that serves as a barrier against an
enemy.

fossil resin Naturally occurring hard resins
such as copal and amber, which are mined and
purified for use in varnishes.

foul drain See soil drain.

foul sewer See soil drain.

foul water A combination of waste and soil
water.

foundation l.Any part of a structure that
serves to transmit the load to the earth or rock,
usually below ground level; the entire masonry
substructure. 2. The soil or rock upon which the
structure rests. 3. The structure on which the
base of a machine rests or to which the feet are
fastened.

434

foxtail wedge

foundation bolt See anchor bolt.

foundation course Same as base course, 1.

foundation drainage tile Tile or piping for
the collection of subsurface drainage, dispersion
of septic tank effluent, and the like.

foundation engineering That aspect of
engineering concerned with the evaluation of
the ability of the earth to support a load, and
with the design of a substructure or transition
member to transmit the load of the superstruc-
ture to the earth.

foundation failure See differential settlement.

foundation investigation A subsurface inves-
tigation.

foundation mat See mat foundation.

foundation pier A column embedded in the
soil that extends from the lowest floor of a
building down to the top of a footing or pile
cap; where the pier, 1 bears directly on the soil
with intermediate footings or pile caps, the
foundation pier is considered to be the entire
length of the column below the lowest floor
level.

foundation pile A relatively long column,
driven in the ground, which supports a load by
bearing on firm material and/or by friction along
its periphery.

foundation planting Plants massed close to
the foundation of a structure.

foundation soil That part of the earth mass
which carries the load of a structure; founda-
tion, 2.

foundation stone l.One of a number of
stones in a foundation. 2. Same as cornerstone.

foundation wall That part of the foundation
for a building which forms the permanent
retaining wall of the structure below grade.

founding, casting Producing metal products in
a foundry by pouring melted metals into molds.

fountain l.See architectural fountain. 2. See
drinking fountain. 3. See soda fountain. 4. See
wash fountain.

four-centered arch An arch whose intrados
is struck from four centers.

four-centered pointed arch See Tudor arch.

four-crib barn See crib barn.

four-leaved flower An ornament used in hol-
low moldings, resembling a flower with four petals.

COUHSED RANDOM

HUBBLE RUBEkE

BUBBLE
MASONRY

foundation walls

four-over- four 1. Descriptive of a double-
hung window having four panes in the upper
sash over four panes in the lower sash; see pane.
2. A floor plan having four rooms on each of
two floors, with a central hall on each floor.

four-part vault A vault formed by the inter-
section of two barrel vaults.

four-piece butt match See diamond matching.

four-square house A one-and-a-half or two-
and-a-half-story house having a square plan with
one room in each corner; a central stairway; usu-
ally a steeply pitched hipped roof or pyramidal
roof; often a kitchen attached to one of the
rooms; also called an American four-square
house.

four-square plan A floor plan for a house hav-
ing four rooms that form a square or rectangle.

four-way reinforcement A system of rein-
forcing bars in flat-slab reinforced concrete con-
struction; consists of bands of bars parallel to two
adjacent edges, and other bands parallel to both
diagonals of a rectangular slab.

fox bolt A bolt having a split end to receive a
foxtail wedge; used as an anchor bolt.

foxtail Same as foxtail wedge.

foxtail saw Same as dovetail saw.

foxtail wedge, fox wedge, fox tenon A
small wedge used to secure the split end of a
tenon in a mortise, the split end of a bolt in a
hole, or the like, by spreading the end as the
wedge is driven in.

435

foxy timber

foxy timber Timber having a reddish cast indi-
cating the onset of decay.

foyer l.An entranceway or transitional space
from the exterior to the interior of a building. 2.
The area between the outer lobby and an audi-
torium. 3. The lobby itself.

FPRF On drawings, abbr. for fireproof.

fps Abbr. for "feet per second."

FPT Abbr. for fan-powered terminal.

fractable A coping on the gable wall of a build-
ing, when carried above the roof; esp. when bro-
ken into steps or curves forming an ornamental
silhouette.

fractables on a coped gable

fracture load See breaking load.

fracture toughness A measure of a member's
ability to absorb energy without fracture.

frake Same as limba.

frame The timberwork or steelwork that
encloses and supports structural components of a
building; see bent frame, doorframe, space
frame, window frame, framing.

frame anchor See doorframe anchor.

frame building Same as framed building.

frame clearance The clearance between a

door and the doorframe.
frame construction Any building primarily

supported by wood or steel structural members,

or some combination thereof; see steel-frame
construction and wood-frame construction.

framed, ledged, and braced door A framed
and ledged door with the addition of one or more
diagonal braces.

framed and braced door Same as framed,
ledged, and braced door.

framed and ledged door A door having rails
and stiles framed together; filled in on one face
with vertical boarding having a thickness less
than the surrounding framing; the vertical board-
ing covers the middle and bottom rails, which are
of less thickness than the top rail and stiles.

framed building A type of building construc-
tion in which the loads are carried to the ground
by a framework, rather than through load-
bearing walls.

framed building

framed door Any door having a rigid frame
made up of a top rail, lock (center) rail, bottom
rail, hanging stile, and lock stile.

framed floor See double floor.

framed ground One of the wood members
fixed around an opening, with a tenon joint
between the head and jambs, level and plumb to
wall faces; used for attaching a wood door casing.

framed house A house of wood-frame con-
struction; also see timber-framed house.

framed joist A joist which has been notched or
otherwise cut to receive other timbers.

436

framing square

framed overhang The projection of an upper
story of a house beyond the story immediately
below it; see overhang, false overhang, hewn
overhang.

DOUBLE
PLATE

framed overhang

framed partition, trussed partition A par-
tition consisting of a covering applied to framing
of studs, struts, and braces which form a truss.

framed square See square-framed.

frame gasket A resilient material, in strip
form, which is attached to doorframe stops to
provide tight closure of the door.

frame-high In masonry, as high as the lintel of
an opening or the top of a door or window frame.

frame house A house of wood frame construc-
tion, usually sheathed and covered with lap or
panel siding or shingles.

frameless partition A partition not having a
supporting frame; for example, a partition of
tempered glass.

frame pulley A pulley, installed in a window
frame, which carries a sash cord.

frame saw Same as gang saw.

frame tie Same as wall tie.

frame wall A wall of wood frame construction.

framework An assemblage of structural ele-
ments or members fitted together to form a struc-
ture, as a multistory building, a rigid-frame shed,
or a truss.

framing 1 . A system of structural woodwork.
2. The rough timber structure of a building,
such as partitions, flooring, and roofing. 3.
Any framed work, as around an opening in an

framing, 2 around an exterior wall opening

exterior wall. See balloon framing, braced
framing, iron framing, platform framing, post-
and-beam framing, post-and-girt framing, post-
and-lintel framing, skeleton framing, western
framing. Also see illustration under timber-
framed house.
framing anchor A metal device used in light
wood-frame construction for joining studs, joists,
rafters, etc.

framing anchor

framing chisel See mortise chisel.
framing drawing See erection drawing.

framing plan A plan of each floor of a building
showing the makeup of beams and girders on
that floor, and their connections, using a simpli-
fied system of symbols and drafting linework.

framing square See carpenter's square.

437

framing table

framing table Same as rafter table.

framing timber One of the structural mem-
bers of a timber-framed house; in colonial Amer-
ica, such massive timbers were usually made of
hand-hewn oak.

Francois I (Premier) style The culmination
of the early phase of French Renaissance archi-
tecture named after Francis I (1515-1547),
merging Gothic elements with the full use of
Italian decoration. Fontainebleau is an out-
standing example. (See illustration p . 439.)

Franco-Italianate style Same as Second
Empire style.

frank To form a miter joint in a sash frame at

the intersection of a crosspiece.
Franklin An obsolete term for a lightning rod.

Franklin stove A freestanding, enclosed, cast-
iron stove, set on short legs with provision for air
circulation around, over, and under its exterior
surfaces; serves the function of a fireplace incor-
porating a grate; usually attributed to Benjamin
Franklin. It is fuel efficient and superior to a fire-
place as a means of heating a house because it is
more fuel efficient and the source of heat is
brought out into the room itself. The amount of
heat the stove radiates can be controlled by reg-
ulating the draft through the stove by means of
an adjustable opening in its front door.

frass A powdery residue in holes bored in wood
by insects, usually by powder-post beetles.

frater A common eating room in a monastery.

fraternity house A building used for social
and residential purposes by an association of
male students called a "fraternity."

F»rating A fire performance rating of a fire-
stopping system, measured in terms of period of
time that the system will limit the passage of fire
through it when tested according to the applica-
ble code.

free area The total minimum area of the open-
ings in an air inlet or outlet (e.g., air diffuser,
grille, or register) through which air can pass;
usually expressed as a percentage of the total
area.

freeboard In a water tank, the vertical distance
between the maximum water level and the top
of the tank.

free convection Same as natural convection.

free delivery-type unit A device which
takes in air and discharges it directly to the space
to be treated without ductwork or other ele-
ments which impose air resistance.

free facade A building's facade that is not
attached to load-bearing columns.

free fall l.The descent of freshly mixed con-
crete into forms without dropchutes or other
means of confinement. 2. The distance through
which such descent occurs. 3. The uncontrolled
fall of aggregate.

free»field room Same as anechoic room.

free float In CPM terminology, the amount of
extra time available for an activity if every activ-
ity in the project starts as early as possible; the
amount of float that can be allocated to an
activity without interfering with subsequent
work.

free-flying staircase A staircase with no
apparent means of support.

free haul The distance within which excavated
material is to be moved without additional com-
pensation.

freehold 1 . A form of tenure of property held in
fee simple, fee tail, or for life. 2. Property so held.

free moisture Moisture not retained or ab-
sorbed by aggregate.

free-span roof A roof that spans from wall to
wall without interior columns or pillars.

freestanding Said of a structural element which
is fixed by its foundation at its lower end, but not
constrained throughout its vertical height.

freestone Fairly fine-grained stone that works
easily; has no tendency to split in any preferen-
tial direction; esp. suitable for carving and elab-
orate milling; usually a sandstone or a granular
limestone.

free stuff See clear lumber.

free tenon A piece of timber having a tenon at
each end; used to join individual timbers by fit-
ting the tenons into corresponding mortises in
the two individual pieces.

free water l.See surface moisture. 2. Water
that is free to move, under the influence of grav-
ity, through a soil mass.

freeze-and-thaw tests A procedure (ASTM
Test Method C666) for evaluating the resistance
of concrete specimens to freeze rapidly in water

438

freeze-and-thaw tests

Francois I
(Premier)

style:
house of

Agnes

Sorel,

Orleans

439

freezer

and then thaw in water, and then to freeze
rapidly in air and thaw in air.

freezer A mechanically refrigerated room or
cabinet for the storage of frozen foods; usually
maintained at a temperature of about 10°F
(approx. — 12°C).

freight elevator, (Brit.) goods lift An ele-
vator used for carrying freight, on which only
the operator and the persons necessary for
unloading and loading the freight are permitted
to ride.

French arch A Dutch arch.

French basement Same as raised basement;
the main entrance to the house is one floor above.

French Canadian architecture See Cajun
cottage and galerie house.

French casement window Same as French
window.

French Colonial architecture A term
descriptive of architecture developed by French
colonists in New Orleans and the Louisiana Ter-
ritory from about 1699 onward. Their architec-
ture persisted until about 1830 — many years after
the territory was no longer French. French Colo-
nial architecture usually characterized by a raised
basement used for utility or commercial purposes;
a symmetric facade with a centrally located front
door; a porch (galerie); typically, a steeply
pitched hipped roof, pavilion roof, or a shingle-
covered bonnet roof supported by wood posts
and/or brick columns; a brick chimney. In New
Orleans, wrought-iron balconies, surrounding
the upper stories and extending over the side-
walk; French doors, with battened or paneled
shutters; transom lights or fanlights above the
front doors of the more elegant homes. Also see
Cajun cottage, Creole architecture, Creole house,
plantation house, raised house. (For a description
of architecture that exhibits the strong ethnic
influences of the immigrant populations of the
Acadians and the Creoles, see French Vernacu-
lar architecture.)

French door, casement door, door window
A door having a top rail, bottom rail, and stiles,
which has glass panes throughout (or nearly
throughout) its entire length; often used in pairs.

French drain, boulder ditch, rubble drain
l.A drain consisting of a trench filled with
loose stones and covered with earth. 2. Same as
drain tile.

French Colonial architecture: Spanish Customs House,
New Orleans

H- ■' . ^V ■:}

M{]

• WW .

— : — ™n~ — ~ '

French door

French drain

440

frequency

French Eclectic architecture Domestic
architecture that emulates many of its French
antecedents, combining elements and characteris-
tics of a wide range of historic style of its
antecedents. Typical characteristics include: a wall
cladding of brick, stone, or stucco; quoins at the
wall intersections; occasionally, decorative half-
timbering; a cylindrical stair tow having a steep
conical roof; a small porch having a balustrade
over the door; a porte cochere; a tall, steeply
pitched, hipped roof with one or more gables,
often tiled or shingled; flared eaves; one or more
massive chimneys; arched dormers, gabled dorm-
ers, or hipped wall dormers that break the line of
the cornice; French windows or double -hung win-
dows; upper-story windows that break the roof
line; an entry door having a stone or terra-cotta
door surround or having pilasters on each side.

French embossing A method of etching glass
with acid to produce lettering or ornamentation.
As many as four strengths of hydrofluoric acid
(or acid plus a buffering alkali) may be employed
to produce an equal number of different surface
textures.

French flier, French flyer A flier of a three-
quarter-turn stair, around an open well.

Frenchman A tool used for pointing mortar
joints.

French method of application A method
of applying roofing shingles; at least three cor-
ners are clipped so that they form a hexagonal
pattern when laid with their diagonals perpen-
dicular to the eaves of the roof; they lap both at
the top and sides.

French Norman style A style of architecture
based on the architecture of houses in Nor-
mandy and Brittany after about 1920; usually
characterized by steep, conical roofs or hipped
roofs, stucco walls, round stair-towers, and an
asymmetrical plan.

French polish 1 . A furniture polish or finish con-
taining shellac mixed with alcohol or oil; French
varnish. 2. A hand-rubbed high-gloss finish,
achieved by multiple applications of such varnish.

French Revival See French Eclectic architec-
ture.

French roof A term sometimes used for a
mansard roof whose sloping sides are nearly per-
pendicular.

French roof

French sash See French window.

French Second Empire style See Second
Empire style.

French stuc An imitation stone formed by
plasterwork.

French tiles A type of interlocking roof tiles.

French truss See Fink truss.

French varnish See French polish, 1.

French Vernacular architecture In America,
architecture found primarily in Louisiana and in
many early settlements along the Mississippi River;
it exhibits the influences of two major French-
speaking immigrant populations. The first group,
from Canada, the Acadians, whose descendants are
now known as Cajuns, settled in the bayou districts
of Louisiana during the last half of the 18th century
in modest houses known as Cajun cottages. The
second major ethnic group consisted of the Creoles,
persons of European ancestry born in the Missis-
sippi Valley, the Gulf Coast, or the West Indies,
who usually spoke a French patois; their dwellings
are known as Creole houses. For specific aspects of
this architecture see abat-vent, banquette cottage,
barreaux, bluffland house, bonnet roof, bousillage,
briquette-entre-poteaux, cabanne, columbage,
faux bois, faux marbre, piece sur piece construc-
tion, pierrotage, pilier, plaunch debout en terre
construction, poteaux-en-terre house, poteaux-
sur-solle house, raised house.

French Victorian style See Second Empire
style in the United States.

French white See silver white, 2.

French window A casement window extend-
ing down to the floor; also called a French door.

French-window lock See cremone bolt.

frequency The number of oscillations per sec-
ond (a) of the current or voltage in an alternat-
ing-current electric circuit, or (b) of a sound wave,

441

fresco

or (c) of a vibrating solid object; expressed in hertz
(abbr. Hz) or in cycles per second (abbr. cps).

fresco, buon fresco The technique of
painting water colors on plaster when it is
almost but not quite dry; in such work, water-
based colors unite with the base; any retouch-
ing is done when the plaster is dry (i.e., fresco
secco).

fresco secco, secco A mural, often fugitive,
painted with water-based colors on dry plaster.

fresh air Air taken into a building from the out-
doors.

fresh»air inlet A vent connection to a house
drain, on the building side of the main drain
trap.

fresh»air intake Same as outside-air intake.

fresh concrete Unhardened concrete capable
of being consolidated.

Fresnel lens In lighting, a lens that concen-
trates light from a small source such as an incan-
descent filament; similar to but thinner and
lighter than a plano-convex lens owing to steps
on the convex side; used in many types of lumi-
naires, esp. downlights and spotlights.

fresnel lens

lie

Fresno scraper Same as buck scraper.

fret l.An ornament, sometimes painted,
incised, or raised and formed of short fillets,
bands, or reglets variously combined, frequently
consisting of continuous lines arranged in rect-
angular forms; a meander; a Greek key. 2. Sim-
ilar ornamentation in which the fillets intersect
at oblique angles, as often in Oriental designs.

fretsaw A fine-toothed saw having a narrow
blade which is held under tension, in a frame;
used to cut thin wood, esp. ornamental designs.

fretty A series of knots used as a decorative
element.

fretwork Ornamental openwork or interlaced
work in relief, esp. when elaborate and minute
in its parts, and of patterns of contrasting light
and dark.

fret patterns

friable Easily crumbled or pulverized; easily
reduced to powder.

F.R.I.B.A. Abbr. for "Fellow of the Royal Insti-
tute of British Architects."

friary A monastery of friars, especially those of a
mendicant order.

friction The resistance to relative motion, slid-
ing or rolling, of the surfaces of bodies in contact.

friction brake A device for slowing down or
stopping a moving mechanism by friction
between two surfaces which rotate or slide over
each other.

friction catch Any catch which, when it
engages a strike, is held in the engaged position
by friction.

friction catch

friction-grip bolt See high-tension bolt.

friction head In a piping system, the pressure

drop expended in overcoming frictional resis-
tance to flow.

friction hinge A door or window hinge which
will remain open at any selected position,
because of friction in the hinge.

friction loss In concrete construction, the
stress loss in a prestressing tendon resulting from

442

front

friction between the tendon and other devices
during stressing.

friction pile, floating pile foundation A
pile that transfers its load to the soil through
friction with the earth surrounding it; the point
of the pile carries no load.

friction shoe An adjustable or preloaded fric-
tion device used to hold a sash in any open
position.

friction tape A fibrous tape which is impreg-
nated with a sticky moisture-resistant com-
pound; used in electric wiring as a protective
covering for insulation.

friction welding A method of welding ther-
moplastic materials whereby the heat necessary
to soften the components is provided by friction.

frieze l.In Classical architecture and deriva-
tives, the middle horizontal member of three
main divisions of an entablature, above the
architrave and below the cornice. 2. A decora-
tive band at or near the top of an interior wall
below the cornice. 3. In house construction, a
horizontal member connecting the top row of
the siding with the underside of the cornice.
Also see cushion frieze.

frieze, 1

frieze-band window One of a series of small
windows that form a horizontal band directly
below the cornice, usually across the main
facade of a building; found especially in Greek
Revival architecture.

frieze-band windows

frieze panel The topmost panel in a multipan-
eled door.

frieze rail A door rail which is just below the
frieze panel.

frigidarium The cold section of a Roman bath,
sometimes including a swimming pool (piscina).
Also see bath, 3.

frit Small friable particles produced by quench-
ing a molten glassy material.

frithstool A seat, usually of stone, placed near
the altar in some churches as a sacred refuge for
those who claimed the privilege of sanctuary.

froe A riving knife.

frog, panel A depression in the bed face of a
brick or building block; used to provide a better
key for mortar.

a brick having a frog

stage waLl in an

from the frieze, 2 of the Parthenon

frons scaenae The front
ancient Roman theater.

front 1 . The most prominent face of a building
and/or that face which contains the main
entrance. 2. The face of a lock through which the
bolt or bolts move. It is usually mortised in so as to
be flush with edge of door; also called a lock front.

443

frontage

frontage The length of a lot line or a building
site along a street or other public way, or along a
body of water forming a boundary.

frontage line Same as frontage.

frontal The textile or panels which form the
decorative front of an altar.

frontal

front curtain See act curtain.

front door The main entrance to a building or
to an apartment in a building; an entrance
door.

front elevation The facade or principal eleva-
tion of a building.

front-end loader l.A bucket and lift-arm
assembly designed for use on the front of a
tractor; hydraulic cylinders, which raise and
lower the lift arms, tip the bucket so that it
may be dumped in the elevated position. 2.
The entire machine using the above assembly.

front-end loader

3. A self-propelled machine mounted either
on wheels or on crawlers and equipped with a
front-mounted bucket to dig, lift, haul, and
dump into stockpiles, haulers, etc.; a variety of
attachments are available enabling such a
machine to do other types of work, such as rip-
ping, scraping, or ditching.

front foot A foot measured along the front
property line.

front-gabled, front-facing gable Said of a
house having a gable on its facade.

front girt A structural horizontal member (girt)
or beam in an early timber-framed house along
the front face of the house; see illustration under
timber-framed house.

front hearth, outer hearth That part of the
hearth or hearthstone which is on the room side
of the fireplace opening.

frontispiece 1 . The decorated front wall or bay
of a building. 2. An ornamental porch or chief
pediment. 3. A fancy rendering prefacing an
architectural presentation, esp. a student project
in architectural school.

frontispiece entrance The decorative front
wall of a building, often flanked by columns or
pilasters.

front light 1. A lighting unit mounted on the
auditorium side of the proscenium. 2. A light-
ing fixture mounted at dead center of an open
stage.

front lintel A lintel that supports the outer leaf
of a cavity wall.

front of the house Those parts of a theater
which are on the audience side of the fire
wall.

fronton See pediment.

front putty Same as face putty.

front stage The forepart of the stage in a the-
ater, nearest the footlights.

front yard A yard of a plot of ground facing the
street; extends from the front line of the building
to the front property line, and across the full
width of the plot.

frost The action (or result of such action) of the
freezing of water vapor on a surface (e.g., the
ground) that is colder than 32°F (0°C).

frost action The freezing and thawing of
moisture in materials and the resultant effects
on these materials and on structures of which

444

full-cell process

they are a part or with which they are in
contact.

frost boil 1. A defective spot on a concrete sur-
face resulting from swelling and subsequent dis-
integration caused by the action of frost on
entrapped moisture. 2. The softening of soil dur-
ing a period of thaw, owing to the liberation of
water.

frost crack A lengthwise split in a growing tree
caused by frost, usually confined to the base.

frosted 1. Rusticated, with formalized stalac-
tites or icicles. 2. Given an even, granular
surface to avoid shine; matted. 3. Closely reticu-
lated or matted to avoid transparency.

frosted finish See caustic etch.

frosted glass Glass which has been surface-
treated to scatter light or to simulate frost.

frosted lamp bulb A lamp bulb that is chemi-
cally etched or sandblasted to diffuse the emitted
light. Incandescent lamps usually are frosted on
the inside; tungsten-halogen lamps are frosted
on the outside.

frosted 'work A type of ornamental rusticated
work, having an appearance like that of frost on
plants.

agigsffla

IPsSSiB

frosted work

frost heave The raising of a soil surface due to

the accumulation of ice in the underlying soil.
frosting l.A surface haze on the surface of a

paint film caused by very fine wrinkling. 2. A

lusterless finish of metal or glass.
frost line An imaginary line indicating the

depth of frost penetration in the ground.

frostproof closet A hopper, 4 which has no
water in the bowl and has the trap and the con-
trol valve for its water supply installed below the
frost line.

frost-protection blanket Same as curing
blanket.

frow A riving knife.

frowy Descriptive of soft and brittle timber.

frt Abbr. for "freight."

FS On drawings, abbr. for "Federal Specifications."

fsp Abbr. for fire standpipe.

FSTC Abbr. for field sound transmission class.

ft On drawings, abbr. for "foot."

ft-C Abbr. for footcandle.

FTG l.On drawings, abbr. for footing. 2. On
drawings, abbr. for fitting.

FT-LB On drawings, abbr. for "foot-pound."

fuel bunker A receptacle for the storage of
solid fuel.

fuel contribution rating A measure of the
amount of heat energy that building materials
can add to a fire.

fuel-fired boiler Automatic mechanical equip-
ment which utilizes heat from combustion of solid,
liquid, or gaseous fuels to heat water or generate
steam, and having all components including
burner, boiler controls, and auxiliary equipment
assembled in one unit, either at the factory or on
the site.

fuel load The quantity of potential fuel
within a building, including its contents and
fabric.

fugitive Changing in color as a result of lack of
permanency in a colored pigment or medium
when exposed to air, light, etc.

fugitive color Said of the color of a painted
surface that is not colorfast; e.g., color changes
can occur with exposure to sunlight, weather,
and/or with cleaning.

full Of a dimension, slightly oversize.

full bond In masonry, a bond in which all
bricks are laid as headers.

full-bound Descriptive of a sash having stiles
and rails of equal width.

full Cape house A Cape Cod house which has
two double-hung windows on each side of the
front door. (See illustration p . 446.)

full-cell process Same as Bethell process.

445

full-centered

*j=-^

full Cape house

full-centered Applied to an architectural
feature the outline of which follows an arc of a
circle.

full coat A paint film of optimum thickness.

fuller's earth A naturally occurring earthy sub-
stance, somewhat similar to potter's clay but
lacking its plasticity; used as a poultice to
remove stains from stonework on a building.

Fuller faucet A faucet, the flow through
which is controlled by means of a rubber ball
that is forced into the opening of the pipe.

full-facade portico A portico that extends
the full width of a house and its full height.

full-facade portico

full-flush door A door of hollow-metal con-
struction, formed from two sheets of steel. The
top and bottom of the door may be either flush
or closed by end channels; seams are visible on
door edge only.

full frame See braced frame.

full glass door A door having glass (usually
heat-strengthened or tempered) in the entire
area between the rails and stiles; may have hori-
zontal muntins dividing the glass area.

full gloss A very high gloss.

full header A brick course consisting entirely
of headers, 1.

full-height porch A roofed porch, on the
front of a house, that extends the full height of
the house but not necessarily the full width.

full house A house having rooms symmetrically
located on both sides of a chimney; for example,
see the illustration under full Cape house.

full-louvered door A type of door having lou-
vers the entire height and width of the area sur-
rounded by rails and stiles.

fullness A measure of the amount of gather of a
drape or curtain covering an opening; expressed
as a percent by which the total area of the drape
exceeds the area of the opening. For example,
100% fullness indicates that the drape is 100%
wider than the width of the opening.

full-open valve A shutoff valve whose cross
section, in the open position, equals at least 85%
of the cross-sectional area of the connecting pipes.

full-penetration butt weld A butt weld
between two members in which the depth of the
weld is equal to the thickness of the smaller of
the two members.

full size A drawing at the same size as the object
shown.

full splice A splice equal to the full strength of
its members.

full-surface hinge A hinge designed for
attachment on the surface of the door and jamb
without mortising.

® T

: ©

JAMB
LEAF

DOOR
LEAF

full-surface hinge

446

furring nail

full torching See torching.

full-way valve See gate valve.

full-width porch A porch that extends the
full width of a house, but not the full height.

fully- tempered glass Glass that has been
tempered, 3, as specified in ASTM CI 048 or an
equivalent document. As a result of tempering,
it may be as much as five times stronger than
annealed glass of the same thickness.

fully welded seamless door A door having
all joints on its faces and vertical edges continu-
ously welded and finished flush and smooth, so
as to be completely invisible.

fumed oak Oak which has been darkened by
exposure to ammonia fumes.

fume hood A partial enclosure through which
air is drawn to remove gases and odors within
the enclosed area.

functional spaces The spaces and rooms
within a building that house the major activities
for which the building or facility was intended.

functionalism A philosophy of architectural
design asserting that the form of a building
should follow its function, reveal its structure,
and express the nature of its materials, construc-
tion, and purpose, minimizing or eliminating all
purely decorative effects. See Louis H. Sullivan's
1896 statement on this subject, ". . . form ever
follows function," under Sullivanesque.

fundula In ancient Rome, a blind alley; a cul-
de-sac.

fungicide A substance that is poisonous to
fungi; retards or prevents the growth of fungi.

fur To apply furring.

furnace l.That part of a boiler or warm-air
heating plant in which combustion takes place.
2. A complete heating unit for transferring heat
from fuel being burned to the air supplied to a
heating system.

furnace slag Same as blast furnace slag.

furnish By-products from primary wood manu-
facturing such as planer shavings, sawdust, and
slabs; used as a raw material in fabricating parti-
cleboard, fiberboard, etc.

furniture See door furniture.

furniture wall A hollow metal partition con-
taining vertical and horizontal slots through
which electrical cables can be run.

furred Provided with furring strips so as to leave
an air space, as between plastering and a wall or
between flooring and the subfloor.

furring 1. Spacers such as wood strips or metal
channels which are fastened to the joists, studs,
walls, or ceiling of a building so that the finish
surface may be leveled. Also see wall furring. 2.
Grillage for the attachment of gypsum or metal
lath. 3. A method of finishing the interior face
of a masonry wall to provide space for thermal
insulation, to prevent moisture transmission, or
to provide a level surface for finishing. 4. Same
as scale, 8.

PLASTER

FURRING
CHANNELS

METAL
LATH

furring

furring brick A hollow brick used for furring
or lining the inside face of a wall; usually the size
of an ordinary brick and grooved or scored on
the face to afford a key for plastering; carries no
superimposed load.

furring channel A steel channel used as fur-
ring, 1.

furring channel clip Same as channel clip.

furring nail A galvanized, low-carbon steel nail,
usually having a flat head and a diamond point,
with a washer or spacer on the shank for fastening
wire lath and spacing it from the nailing member.

fc®

furring nails

447

furring strip

furring strip A wood strip used as furring, 1;
also see batten, 3.

furring tile Tile designed for lining the inside
of exterior walls and carrying no superimposed
load; has a corrugated surface to receive plaster.

furring tile

furrowed Said of (margin drafted) ashlars

which have vertical grooves cut in the face.
furrowing A technique used in bricklaying to

increase the speed of work; the bricklayer creates a

furrow in the mortar bed with the tip of his trowel.
fus Abbr. for "fusible."
fusarole A molding of convex rounded section,

commonly carved into beads and the like.

fuse An overcurrent protective device consist-
ing of a metal strip, ribbon, or wire which is

fuse of the cartridge type

designed to open an electric circuit by melting if

a predetermined current is exceeded.
fuse block Same as fuse board,
fuse board A panel on which fuse holders

(such as "fuse clips") are mounted.
fuse box A cutout box containing the fuses for

an electric circuit.
fuse lighter A special device for the purpose of

igniting safety fuses.

fusible-element sprinkler In a fire protec-
tion system, a sprinkler which opens under the
influence of heat by the melting of a component
(e.g., a fusible plug).

fusible link A metal chain link made of a low-
melting-point alloy; in case of fire, the chain
breaks, thereby closing a damper, door, or the like.

fusible metal An alloy having a low melting
point; esp. used to release fire-protection devices
in the event of fire.

fusible plug Same as fusible link.

fusible solder An alloy, usually containing bis-
muth, having a low melting point — below that
of tin-lead solder, i.e., below 361°F (183°C).

fusible switch An electric switch with fuse
holders.

fusible tape See joint tape.

fusion In welding, the melting together of filler
metal and base metal, or of the base metal alone,
which results in coalescence.

fust The shaft of a column or pilaster.

fuzzy texture A defect in a porcelain enamel
surface characterized by a myriad of minute bub-
bles, broken bubbles, and dimples.

FW Abbr. for flash welding.

448

G l.On drawings, abbr. for "gas." 2. On draw-
ings, abbr. for girder.

ga. Abbr. for gauge or gage.

gabbro Igneous rock similar to diorite, predom-
inantly composed of ferromagnetic minerals
with crystals visible to the eye; has the same
mineral composition as basalt.

gabion A cylindrical wicker or metal basket
that is filled with stones; used in the construc-
tion of foundations.

gable 1. A vertical surface commonly situated
at the end of a building, usually adjoining a
pitched roof; its shape depends on the type of
roof and parapet, although most often it is tri-
angular; often extends from the level of the
cornice up to the ridge of the roof. If the gable
is on the facade rather than the back end, the
building is said to be front-gabled. 2. A similar
end that is not triangular in shape; for example,
a gambrel end (US). For definitions and illus-
trations for particular types see bell gable, bro-
ken gable, clipped gable, corbie gable,
corbiestep gable, cross gable, crowfooted gable,
crowstep gable, curvilinear gable, docked
gable, Dutch gable, end gable, facade gable,
Flemish gable, front-gabled, hanging gable,
intersecting gable, multicurved gable, parapet
gable, segmental gable, side gable, stepped
gable, straight-line gable, truncated gable, turn-
bled-in gable, wall gable.

gableboard See bargeboard.

gable coping The protective cap covering a
gable wall that projects above the line of the roof
finish.

gable dormer, gabled dormer Same as tri-
angular dormer.

gable elbow A single step at the base of a

straight-line gable.
gabled roof See gable roof.

gabled tower A tower finished with a gable on
two sides or on all sides, instead of terminating
in a spire, or the like.

gable end A wall of a building having a gable at
its end; a gable wall; also called a gable-end wall.

1M »

gable end

gable finish The molding or cornice around a
gable end, usually on the eaves of a building.

gable front A facade that is front-gabled.

gable-front-and-wing plan The plan of a
house having its long side perpendicular to the
street and having a gable on the end facing the
street; a wing is added at the rear of the house.

gable-fronted Same as front-gabled.

gable-on-hip roof A hipped roof in which the
hips are not carried all the way to the ridge;
instead, each end roof surface turns vertically
near the top so as to form a small gable that is
perpendicular to the ridge.

gable-on-hip roof

gable ornamentation Any type of decorative
element on the face of a gable, such as spindle-
work, near the apex of a gable.

gable post A short post located at the peak of a
gable into which the bargeboards are fixed.

449

gable roof

gable roof A roof having a single slope on each
side of a central ridge; usually with a gable at one
or at both ends of the roof.

gable shoulder Projecting brickwork or masonry
which supports the foot of a gable.

gable springer, skew block, skew butt A

kneeler, 1 (esp. a projecting one) which is at the
foot of a gable or the like.
gablet A small ornamental gable.

gable vent A louvered opening in the gable of
a roof; used to exhaust air from an attic.

gable 'wall A wall which is crowned by a gable.

gain joint

gaine A decorative pedestal, esp. one tapered
downward and square in section. Also see estipite.

gal On drawings, abbr. for "gallon."

galena In Spanish Colonial architecture, an
open, covered porch, usually arcaded, either fac-
ing a patio or the street.

galerie A gallery or porch. In French Vernacu-
lar architecture of Louisiana, a roofed porch,
usually open-sided, often extending across the
entire front, across the front and one or more
sides, or completely around the building on the
upper level.

gable wall

gable window l.A window in a gable. 2. A
window shaped like a gable.

gaboon, okoume A wood resembling African
mahogany but softer and lighter in weight.

gadroon, godroon An ornament composed
chiefly of ovoid or more elongated bosses regu-
larly repeated, side by side.

gage See gauge.

gaged See gauged.

gaged brick See gauged brick.

gaging See gauging.

gag process The process of bending structural
shapes in a gag press.

gain In carpentry, a groove or notch in one
piece into which another piece is fitted.

derie surrounding a raised h<

galerie house, gallery house In French Ver-
nacular architecture, a farmhouse or plantation
house evolved by French-speaking settlers in the
Louisiana Territory; usually has a roofed galerie
either across the facade or across the facade and
one or both sides of the house; typically has
gabled dormers with windows. Also see Cajun
cottage and Creole house.

450

gambrel end

galilee A narthex or chapel at the entrance of a
church; often used for worship.

galilee porch A galilee that has direct commu-
nication with the exterior of a church; can be
considered as a vestibule to the principal part of
the church.

gall Unusual growth of plant tissues; a result of
the introduction of a foreign substance such as a
chemical or fungus, or a result of mechanical
injury.

gallery 1. A long, covered area acting as a cor-
ridor inside or on the exterior of a building, or
between buildings. 2. An elevated area, interior
or exterior, e.g., minstrel gallery, music gallery,
roof gallery. 3. An elevated section of the seat-
ing area of an auditorium, esp. the uppermost
such space. 4. In buildings for public worship, a
similar space, sometimes set apart for special
uses. 5. A service passageway within a building,
or linking a building underground to exterior
supplies or exits. Some service galleries also
serve sightseers, e.g., the lighting gallery in the
base of the dome at St. Peter's, Rome. 6. A long,
narrow room for special activities like target
practice, etc. 7. A room, often top-lit, used for
the display of art works. 8. A building serving
such art needs. 9. See long gallery. 10. Any
raised working platform at the side or rear of a
theater stagehouse. 1 1. An arcade, 2. 12. (Brit.)
A device, attached to a lampholder, for support-
ing a reflector, shade, etc.

| | GREAT HALL j J

Bp T GALLERY^

gallery, 1

gallery apartment house An apartment
house having external passageways which pro-
vide entry to individual apartments on each
floor.

gallery grave A prehistoric burial place con-
sisting of a long stone-lined gallery without a
tomb chamber, and covered by an artificial
mound.

gallet A stone chip or spall.

galleting, garreting l.The insertion of stone
chips into the joints of rough masonry to reduce
the amount of mortar required, to wedge larger
stones in position, or to add detail to the appear-
ance. 2. Pieces of tile used to provide a suitable
bed for ridge tile or hip tile. 3. The insertion of
small pieces of flint or colored stone in soft mor-
tar; serves as a decorative element.

gallows bracket A triangularly shaped bracket
fixed to a wall, such as one to support shelving.

GALV On drawings, abbr. for "galvanize."

galvanic anode See sacrificial anode.

galvanic corrosion An electrochemical action

which takes place when dissimilar metals are in
contact in the presence of an electrolyte, result-
ing in corrosion.

galvanize To coat steel or iron with zinc, as, for
example, by immersing it in a bath of molten
zinc.

galvanized iron Sheet metal of iron coated
with zinc to prevent rusting; used extensively for
flashings, roof gutters, gravel stops, flexible
metal roofing, etc.

galvanized pipe A steel pipe or wrought-iron
pipe, of standard dimensions, which has been
galvanized by coating it with a thin layer of zinc.

galvanizing The process of coating steel or
iron with zinc by immersing it in a bath of
molten zinc.

gambrel end An end wall of a structure having
a gambrel roof.

gambrel end

451

gambrel roof

gambrel roof, gambrel 1 . ( VS ) A roof which
has two pitches on each side; in Great Britain
called a mansard roof. 2. (Brit.) A roof which
has a small gable near the ridge on one end; the
part of the roof below the gable is inclined. Also
see Dutch gambrel roof, English gambrel roof,
Flemish gambrel roof, New England gambrel
roof, Swedish gambrel roof.

game room A room used primarily for recre-
ation, often downstairs in a dwelling.

gamma protein Protein obtained from soya
beans; used as a thickener in water-base paints.

gang boarding See cat ladder.

ganged form Prefabricated panels which are
joined to make a much larger unit, for conve-
nience in erecting, stripping, and reusing; usu-
ally braced with wales, strong-backs, or special
lifting hardware.

Gang Nail A registered trademark of Gang-
Nail Systems, Inc. A type of timber connector
consisting of a metal plate having a series of
spikes at right angles to it.

gang saw A powered assemblage of parallel rec-
iprocating saw blades; used to cut a quarry block
into slabs; generally utilizes a loose abrasive
material with water, or diamond or tungsten car-
bide blade inserts, to effect the cutting.

gangway l.A platform or boardwalk erected
over an unfinished building section to provide
access for men and materials carriers. 2. British
term for aisle.

ganister A product made by mixing ground
quartz with a bonding material such as fireclay.

gantry A framework, usually of heavy timbers,
to support building equipment or to provide a
working platform.

gantry crane A revolving crane, positioned
atop a movable pedestal that travels along tracks;

can reach a more extensive area of a construction
site than a stationary crane of similar size.

gap An opening, as in a wall; an open joint.

gap-filling glue A glue used to join surfaces
which cannot be closely fitted together.

gap-graded aggregate Aggregate having a
particle-size distribution characterized by gap
grading.

gap-graded concrete Concrete which con-
tains gap-graded aggregate.

gap grading A particle-size distribution for
material such as an aggregate in which particles of
certain intermediate sizes are substantially absent.

gar. Abbr. for garage.

garage 1. Building or part thereof where motor
vehicles are kept. 2. Place for repairing and
maintaining such vehicles. Also see attached
garage, detached garage.

garage door See overhead door.

garbage Animal and vegetable waste from
restaurants, hotels, markets, and like installa-
tions; contains up to 70% moisture and up to 5%
incombustible solids. Also see refuse, rubbish,
and trash.

garbage chute See refuse chute and gravity-
type refuse chute.

garbage-disposal unit Same as waste-disposal
unit.

garconniere A bachelor apartment. In French
Vernacular architecture, a bachelor's residence
that is separate from the main house.

garden A plot of ground used principally for
growing vegetables, fruits, or flowering and/or
ornamental plants.

garden apartment 1. Ground-floor apart-
ment with access to a garden or other adjacent
outdoor space. 2. Two- or three-story apartment
buildings with communal gardens, generally
located in the suburbs.

garden arch An archway in a garden, often of
lattice construction, that serves as a decorative
structure on which to grow vines, roses, or other
climbing plants.

garden city A residential development having
parking areas; esp. planned to provide consider-
able open space that is well planted with trees
and shrubs.

garden flat Same as garden apartment.

452

gaseous discharge lamp

garden house A structure for shelter in a gar-
den, usually small.

garden tile Structural ceramic units made in
molds and placed as stepping stones through a
garden or patio.

garden wall bond See English garden wall
bond, Flemish garden wall bond, mixed garden
wall bond.

garden wall cross bond In brickwork, a bond
in which a course of headers alternates with a
course consisting of a header followed by three
stretchers.

garderobe l.See wardrobe. 2. A small bed-
room or study. 3. Euphemism for a latrine in
medieval buildings.

garetta Same as garretta.

gargoyle A waterspout projecting from the roof
gutter of a building, often carved grotesquely.

gargoyle

garland An ornament in the form of a band,

a wreath, or a festoon of leaves, fruits, or flowers.
garland drain A shallow ditch or trench for

draining surface or subsoil water before it

reaches an excavation.
garner Same as granary.
garnet A mineral having many varieties in color

and constituents but the same general chemical

formula, with an isometric crystal structure.
garnet hinge Same as cross-garnet hinge.
garnet paper An abrasive paper coated with

finely powdered garnet; used in finishing and

polishing surfaces.

garret 1. Space within a roof structure; some-
times called an attic. 2. A room, usually with
sloping ceilings, just beneath the roof of a house.

garreting See galleting.

garric bolt A tempered-steel device having a
wedge-shaped termination that is fitted into a
dovetailed recess in a stone block or other
masonry unit for the purpose of lifting it; similar
to, but smaller and stronger than, a lewis bolt.

garrison house l.An early fortified house
generally constructed of stone or hewn logs,
commonly with a second-story overhang; com-
monly fitted with loopholes; provided a family
with a safe haven of refuge in times of emer-
gency and served as a one-family dwelling in
times of peace. 2. A modern term sometimes
applied to any Colonial Revival house having an
overhanging second story.

garrison house, 1

garth The open courtyard of a cloister, often
a lawn.

gas burner One or more holes through which a
combustible gas flows and burns.

gas checking A wrinkling in a paint or var-
nish finish which, as it sets, is exposed to burnt
coal gas.

gas concrete Lightweight concrete produced
by developing voids by means of gas gener-
ated within the unhardened mix (usually from
the action of cement alkalies on aluminum
powder used as an admixture). Also see aerated
concrete and foamed concrete.

gas distribution piping All piping from the
house side of the gas meter to the consumer
service pipes used to supply fuel or illumination
to a building.

gaseous discharge The emission of light from
gas atoms excited by an electric current.

gaseous discharge lamp A lamp that pro-
duces light by means of an electrical discharge of

453

gas-filled lamp

gas inside the bulb; the most commonly used

gases are neon, helium, and xenon.
gas-filled lamp An incandescent lamp in

which the filament operates in an inert gas

atmosphere within the bulb.
gas-fired Heated by the combustion of gaseous

fuel.
gas-fired water heater A direct-fired water

heater using natural gas, manufactured gas, or

propane gas as its source of fuel.

PRESS AND TEMP VALVE

COLD INLET

ANTI-SIPHON
HOLE
DIP TUBE

INSULATION

GAS SUPPLY

THERMOSTATIC
CONTROLLER

THERMOCOUPLE
AND PILOT BUHNER

COCK
MAIN BURNER

COMBUSTION
CHAMBER

gas-fired water heater

gas flow meter An instrument for measuring
the velocity or volume of flowing gases.

gas furnace A furnace which uses gas as a fuel.

gasket 1. A continuous strip of resilient material
attached to a door or doorframe to provide a tight
seal between the door and frame; acts as weather
stripping and as a light and sound seal. 2. Any
ring of resilient material, used at a joint to prevent
leakage.

gasket glazing Glazing which is set into an
opening and held in place by an elastomeric
gasket.

gasketed joint A joint utilizing a gasket under
compression to join cast-iron soil pipe and
ductile-iron sewer and pressure pipe. The end of
each pipe must be of a type suitable for the indi-
vidual joint.

gas main The line from the public utility which
supplies gas to the consumer service pipes.

VENT PIPE

gasketed joint

gas metal-arc welding An arc-welding process
in which coalescence is produced by heating with
an arc between a consumable electrode (of filler
metal) and the work.

gas meter A mechanical instrument for measur-
ing the amount of gas volume passing a given point.

gas-meter piping The piping from the gas
service-line valve to the outlet of the gas-meter
regulator in a building.

454

gate valve

gas piping system The collective gas service
piping, gas meter piping, and gas distribution
piping.

gas pliers Sturdy pliers having concave jaws
with serrated faces; esp. useful for gripping pipe
or other round objects.

gas pocket, blowhole A hole or void, as in a
casting, which results from entrained air.

gas pressure regulator A device for control-
ling and maintaining a uniform gas pressure;
required when (a) the pressure of the gas supply is
higher than the pressure at which the branch sup-
ply line or gas-utilization equipment is designed
to operate, or (b) the pressure varies beyond
design limits of the utilization equipment.

gas refrigeration Refrigeration involving the
use of machinery in which the refrigerant is
heated by a gas flame.

gas room A fully enclosed room, separately
ventilated, in which toxic and highly toxic com-
pressed gases and associated equipment and sup-
plies are used or stored.

gas service-line valve The valve located at
(or below) grade on the supply side of a gas
meter or service regulator.

gas service piping The gas supply piping from
the street gas main up to and including the gas
service-line valve.

gas station A building or stand where fuel for
motor vehicles is sold. Facilities for motor vehi-
cle repair are often a part of the station.

gas vent A vent pipe leading to the outside air
from a gas furnace or other gas-fired equipment
for removal of gaseous products of combustion.

gas 'welding Any one of a group of welding
processes in which coalescence is produced by
heat from one or more gas flames; sometimes a
filler metal is used; pressure may or may not be
applied to the materials being welded.

gatch Plaster as used in Persia for decorative
purposes.

gate A passageway through a fence, wall, or
other barrier, which slides, lowers, or swings
open or shut.

gate contact See car door contact.

gatehouse A building, enclosing or accompa-
nying a gateway for a castle, manor house, or
similar buildings of importance.

gatehouse

gate operator An electro-mechanical device
which opens or closes a gate when a switch sup-
plies it with voltage.

gate pier A brick, concrete, or stone gatepost.

gatepost A post, usually one of a pair, between
which a gate swings or slides; see hanging post.

gatepost

gate tower A tower containing a gate to a
fortress. (See illustration p. 456.)

gate valve, full-way valve A flow control
device consisting of a wedge-shaped gate which
can be raised to allow full, unobstructed flow or
can be lowered to restrict the flow passage; not
intended for close fluid flow control nor for very
tight shutoff. (See illustration p . 456.)

455

gateway

gate tower

Stem

Disc

Body

Wheel

Bonnet

gate valve

gateway 1. A passage through a fence or wall.

2. A frame, arch, etc., in which a gate is hung.

3. A structure at an entrance or gate designed for
ornament or defense.

gather See fullness.

gathering A transition between two sections
(as in a chimney, flue, or duct) which have dif-
ferent areas.

gauge box Same as batch box.

gateway: Merton College, Oxford (1416)

gauge, gage 1. The thickness of sheet metal or
metal tubing, usually designated by a number.
2. The diameter of wire or a screw, usually desig-
nated by a number. 3. The distance between two
points, such as parallel lines of connectors. 4. A
strip of metal or wood used as a guide to control
the thickness of a bituminous or concrete
paving; called a screed when used in plastering.
5. A measuring instrument, esp. one for measur-
ing liquid level, dimensions, or pressure. 6. See
mortise gauge. 7. In roofing, the length of a
shingle, slate, or tile that is exposed when laid.
8. The quantity of gauging plaster used with
common plaster (lime putty) to hasten its set-
ting, etc. 9. To mix gauging plaster with lime
putty, to effect better control of the set, to pre-
vent shrinkage of the lime putty, and to increase
its strength. 10. To cut, chip, or rub stone or
brick to a uniform size or shape.

gauge board l.Same as gauging board. 2. A
pitch board.

gauged Descriptive of a material which has
been ground so that various pieces are of the
same thickness or of a desired shape.

456

gelling

gauged arch An arch of wedge-shaped bricks
which have been shaped so that the joints radi-
ate from a common center.

gauged arch

gauged brick 1. A brick of special shape that
has been cut with a chisel or saw and then
ground (for example, on coursed sandstone) to
accurate dimensions. 2. A tapered arch brick.

gauged mortar Mortar consisting of a mixture
of cement, lime, and sand in specified propor-
tions.

gauged skim coat In plastering, a very thin
final coat of gauging plaster and lime putty,
troweled to a smooth, hard finish.

gauged stuff A term occasionally used for lime
plaster or for lime mortar.

gauged work 1 . A precise brickwork in which
bricks are cut or sawn to shape and then rubbed
to an exact size and smooth finish. 2. Plastering,
such as the application of moldings or orna-
ments, which is done with gauged plaster.

gauge glass A device which indicates the level
of a liquid in a tank, vessel, or the like.

gauge pile See guide pile.

gauge pressure The pressure, of a gas or liq-
uid, minus the value of atmospheric pressure.

gauge rod A measuring stick for checking the
accuracy of the gauge in brickwork; called a
story rod if used to mark floor and sill levels.

gauge stick See scantle.

gauging The addition of a measured quantity of
material to lime mortar in order to modify its
properties.

gauging board A board on which cement,
mortar, or plaster is mixed.

gauging box A batch box.

gauging plaster A special gypsum plaster
mixed with lime putty; used as a finish coat.

gaul A hollow spot or area in a coat of plaster,
mortar, or the like.

gault brick A brick made from a mixture of a
heavy thick clay soil and sand that produces a
color of brick between white and pale yellow,
depending on the percentage of clay.

gauze l.Any thin, open-weave, woven fabric;
usually transparent. 2. A fine wire cloth; also
called lawn.

gazebo A small ornamental structure, such as a
pavilion, often providing a splendid view; usu-
ally built in a garden, in a park, or along a
stream; same as belvedere or summerhouse.

gazebo

gazophylacium A place where precious items
were deposited, as a treasury in a palace or in a
church.

GB Abbr. for glass block.

GC Abbr. for "General Contractor."

G-cramp A large C-clamp, used by joiners.

geison A projection from the face of a wall such
as from a cornice or coping.

gel A semisolid material, somewhat elastic, com-
posed of matter in a colloidal state that does not
dissolve; remains suspended in a solvent. Also
see cement gel.

gelatin mold A semirigid mold made from
gelatin; used in making plaster casts.

gel coat A thin, outer layer of resin, sometimes
containing pigment, applied to a reinforced plas-
tic molding to improve its appearance.

gelling Any process whereby paint or varnish
thickens to jelly-like consistency. Also see
livering.

457

gemel

gemel, chymol, gimmer, gymmer, jimmer

Two corresponding elements of construction
considered as a pair.

gemel window A window built into a pair of
openings; a window having two bays.

geminated Coupled, as in coupled columns.

general bid A bid by a person seeking to
become the contractor or general contractor on

a project, as opposed to someone seeking to
become a subcontractor.

general conditions That part of the contract
documents (of the contract for construction)
which sets forth many of the rights, responsibili-
ties, and relationships of the parties involved.
Also see conditions of the contract.

general contract 1. Under the single con-
tract system, the contract between the owner
and the contractor for construction of the
entire work, 1. 2. Under the separate contract
system, that contract between the owner and a
contractor for construction of architectural and
structural work.

general contractor The prime contractor

who is responsible for most of the work at the
construction site, including that performed by
the subcontractors.

general diffuse lighting Lighting from
luminaires which distribute 40% to 60% of the
emitted light upward and the balance down-
ward.

General Grant style A term occasionally
used in the United States for the Second Empire
style of architecture because of the number of
public buildings in this style erected when he
was president of the United States (1869-
1877).

general hospital An institution, consisting
of a building or buildings, in which patients,
irrespective of sex and age, receive diagnostic
and therapeutic medical and surgical services
for most forms of illness, injury, or disability.

general industrial occupancy The use of

a building of conventional design for all types
of manufacturing operations, except high-
hazard.

general lighting Lighting designed to provide
a substantially uniform level of illumination
throughout an area.

generally accepted standard A specifica-
tion, code, rule, guide, or procedure in the field
of construction, or related thereto, recognized
and accepted as authoritative.

general requirements The title of Divi-
sion 1 of the AIAs uniform system for con-
struction specifications, data filing, and cost
accounting.

generator A machine that converts mechani-
cal power into electric power.

generator set A unit consisting of an electric
generator driven by an engine.

genets In Early English style architecture, cusps
in the arch of a doorway.

gentriflcation The upgrading of urban prop-
erty in a deteriorated area, usually resulting in
the dispersal of the current residents and their
replacement by a more affluent population.

geodesic dome A structure consisting of a
multiplicity of similar, light, straight-line ele-
ments (usually in tension) which form a grid in
the shape of a dome.

geodetic survey A land survey in which the
curvature of the earth is considered; applicable
for large areas and long lines; used for the precise
location of basic points suitable for controlling
other surveys.

geometrical stair A stair constructed around a
stairwell without the use of newels at the angles
or turning points.

geometrical stair

Geometric style The early development of
the Decorated style of English Gothic archi-
tecture, in the first half of the 14th cent., char-
acterized by the geometrical forms of its
window tracery.

458

Georgian style

Geometric style

geometric tracery Gothic openwork in the
form of simple geometrical patterns, princi-
pally circles and multifoils.

geometric tracery

Georgian arch Same as camber arch.

Georgian glass See wire glass.

Georgian plan A floor plan of a Georgian-
style house; often two rooms deep, one on each
side of a central hall, with a kitchen added at the
rear of the house. The chimneys are usually
located in the walls on each side of the house.

Georgian Revival See Colonial Revival.

Georgian style In Great Britain, the term
"Georgian" is usually applied to the prevailing

Georgian architecture: typical facade

architectural style during the reigns of George I
through George IV, from 1714 to 1830; derived
from classical, Renaissance, and Baroque forms.
In America, it is applied to a similar architectural
style that emerged about 1700 and flourished
until about 1 780. Georgian architecture is often
characterized by a rectangular plan, often with
symmetrical wings flanking each side; a symmet-
rical brick or stone facade; pedimented gable;
projecting central pavilion or a portico often
with two-story columns; monumental pilasters
extended the full height of the facade; a belt
course; a slate-shingled hipped roof (often trun-
cated and enclosed with a balustrade); a deco-
rated classical cornice; five-ranked rectangular
double-hung windows; lintels above rectangular
windows; front windows on the ground floor,
often pedimented; frequently a Palladian win-
dow; an elaborate front entrance; either a single
door or a double door, with multiple panels in

Georgian architecture: example of a doorway

459

geotechnical investigation

each leaf; often decoratively crowned; a pedi-
ment over the door; often, a projecting hood
above the door; a fanlight or transom light above
the door, often with sidelights on each side of it;
decorative pilasters or engaged columns flanking
the doorway. In elegant homes, the front door
opened into a spacious entrance hall.

The introduction of the Georgian style in
America varied with geographical region. In
New England, two-story timber-framed houses
with central chimneys predominated. In the
South, brick and stone construction were widely
used, with fireplace chimneys at the ends of the
house; in large houses, a raised basement was
common. Although initially relatively unpre-
tentious, Georgian-style homes became larger,
wider, and more elaborate over time. An arbi-
trary distinction is sometimes made by some
architectural historians between Early Georgian
and Late Georgian, considering the year 1750 as
the approximate time of transition. However,
the changes occurred gradually and at different
times in different colonies.

geotechnical investigation A soil boring
and sampling process (together with associated
laboratory testing) required to establish the sub-
surface profiles and relative strengths of the
strata encountered at depths likely to have an
influence on the design of a building project.
Also called a subsurface investigation.

German barn, Swiss barn Any one of a vari-
ety of barns, often serving as a combination barn
and home, built during the 18th and 19th cen-
turies by German-speaking immigrants to the
New World; especially characterized by a shin-
gled gambrel roof or gable roof; a second floor
overhanging one side of the barn, well beyond
the foundation; usually an inclined driveway pro-
viding direct entry to the threshing floor where
wheat was threshed, hay was stored, and where
the family lived. The basement was used as a sta-
ble for horses, cattle, and sheep; often of stone
construction or masonry up to the threshing floor
and wood construction above. Many stone barns
had long, narrow, vertical slots in the walls for
supplying the barn with fresh air. Also see bank
barn, forebay barn, grundscheier, Pennsylvania
barn, Sweitzer barn, slit ventilator.

German Colonial architecture Architec-
ture attributed to German-speaking immigrants

to America primarily in the years from about
1680 to 1780. Many of these early settlers first
built a log house of hewn square timbers as a tem-
porary home until they could construct more
substantial housing. Common characteristics of
their permanent houses included: a symmetrical
facade, thick stone walls, a steeply pitched end-
gabled roof usually covered with wood shingles or
clay tiles; an attic story with windows at the gable
ends and shed dormers on the roof, a porch at the
gable end of the house or at the front of the
house; small casement windows with battened
shutters, later replaced by double-hung windows.
If it was built into a hillside, it was called a bank
house. Also see fachwerk, grundscheier, Pennsyl-
vania Dutch, rauchkammer, springhouse.

German siding Drop siding with a concave
upper edge which fits into a corresponding
groove in the siding above.

gesso A mixture of gypsum plaster, glue, and whit-
ing; applied as a base coat for decorative painting.

geyser An instantaneous-type water heater.

GFCI Abbr. for ground fault circuit interrupter.

ghost trap Same as grave trap.

GI On drawings, abbr. for galvanized iron.

giant arbor vitae Same as thuya.

giant order See colossal order.

giant pilaster Same as colossal pilaster.

gib l.A steel strap used to clasp two members
together. 2. Same as gib or jib door.

gib-and-cotter joint A joint in timber con-
struction, formed with a steel strap tightly drawn
in position by steel clips and wedges.

Gibbs surround The framing of a door or
window by a head composed of a (usually
triple) keystone and by jambs that are bor-
dered by protruding rectangular blocks of
stone.

gib door See jib door.

giglio A Florentine emblem such as a fleur-de-lys.

gig Stick A radius rod.

gild See guildhall.

gilding 1. Gold leaf, gold flakes, brass, etc., applied
as a surface finish. 2. The surface so produced.

gilding metal An alloy containing nominally
95% copper and 5% zinc. Generally available as
flat products, rod, and wire.

460

girdle cornice

Gibb;

•s surround

gilloche See guilloche.

Gilmore needle A device used for determin-
ing the setting time of hydraulic cement.

gilsonite, uintahite A naturally occurring
grade of asphalt used in floor tile, paints, paving,
and roofing.

gimlet A small tool with a pointed screw at one
end; used to bore small holes in wood by turning
it with one hand.

gimmer Same as gemel.

gin block A simple form of tackle block with a
single wheel, over which a rope runs.

gingerbread Highly decorative, elaborate
woodwork, usually turned on a lathe and/or fash-
ioned on a jigsaw.

Gingerbread folk architecture A style of
folk architecture widely applied to homes in
America from about 1870 to 1910; especially
characterized by the heavy use of gingerbread,
spindlework, and ornate bargeboards. Often,
these elaborate embellishments were added to
an older house to update it or included in a new

Gingerbread folk architecture

house to make it appear to be au courant. Heav-
ily ornamented porches were common; in larger
houses, many were two stories high, with deco-
rative balustrades with spindlework balusters
and lacelike spandrels. Also see Carpenter
Gothic, Queen Anne style, Steamboat Gothic,
Victorian architecture.

Gingerbread style A richly decorated Ameri-
can building fashion of the 19th cent.

girandole A branched light holder, either
standing on a base or projecting from a wall.

girder A large or principal beam of steel, rein-
forced concrete, or timber; used to support con-
centrated loads at isolated points along its
length. (See illustration p. 462.)

girder bracket Same as trimming joist.

girder casing The material which totally
encloses a girder, as one that projects below a
ceiling.

girder post Any column or post which supports
a girder.

girding beam See side girt and end girt.

girdle A band, usually horizontal; esp. one ring-
ing the shaft of a column.

girdle cornice A cornice that encircles a
building like a girdle.

461

girt

■ ■s.-m-.-.*-.^'*srs^.*m • . - . - . U^ TT^

FINISH FIOOH

fioofi ;o r sr

■* - ■

/ * j

GIRDER

LEDGER

JOIST

GIRDER

girders supporting floor joists

girt A horizontal structural member in the fram-
ing, 3 of an early timber-framed house, typically
supporting the ends of the ceiling joists and act-
ing as the main horizontal support for the floor
above; often located about halfway between the
groundsill, 2 and the horizontal timber at the top
of the wall (the top plate) The term girt often is

JOIST

STUD

girt, 2

preceded by an adjective indicating its position;
for example, front girt denotes a heavy timber
that runs horizontally along the front of the
house; rear girt denotes a heavy timber that runs
horizontally along the rear face of the house;
chimney girt denotes a heavy timber that acts a
main horizontal support between chimney posts.
See illustration under timber-framed house.

girt board A timber girt.

girt strip Same as ledger board.

GL On drawings, abbr. for glass.

glacial till See till.

glacis A sloped embankment in front of a forti-
fication, so raised as to bring an advancing
enemy into the most direct line of fire.

gland joint In hot water piping, a joint that
permits movement resulting from thermal
expansion or contraction.

gland seal A seal used to prevent leakage
between a fixed part and a movable part.

glare The sensation produced by brightnesses
within the visual field that are sufficiently
greater than the luminance to which the eyes
are adapted to cause annoyance, discomfort, or
loss in visual performance and visibility.

glass A hard, brittle inorganic substance, ordi-
narily transparent or translucent, produced by
melting a mixture of silicates (such as sand) and
a flux (such as lime and soda). Molten glass may
be blown, cast, drawn, rolled, or pressed in a
variety of shapes. Centuries ago, window glass
was thin, generally of poor quality, often green
or violet in hue, streaked with air bubbles. After
about 1700, the manufacturing processes
improved significantly so that the price of glass
dropped significantly, the sizes of panes
increased, and the use of window glass became
more widespread. Also see annealed glass, art
glass, broad glass, crown glass, cylinder glass, fig-
ured glass, float glass, ground glass, insulating
glass, iridescent glass, jealous glass, laminated
glass, leaded glass, muff glass, opalescent glass,
organic-coated glass, painted glass, plate glass,
processed glass, rolled glass, sheet glass, solar
glass, stained glass, tempered glass, Tiffany glass,
tinted glass, toughened glass, wire glass.

glass block, glass brick A hollow block of
glass, usually translucent with textured faces;
has relatively low thermal-insulation and low

462

glazed door

fire-resistance value; used in non-load-bearing
walls.

glass bulb sprinkler In a fire protection sys-
tem, a sprinkler which opens under the influ-
ence of heat by the breakage of a glass bulb; the
bulb breaks as a result of the pressure exerted by
the expansion of the liquid which it contains.

glass cement Any binding material used to
cement glass to another piece of glass or other
material.

glass cloth A closely-woven cloth fabricated of
glass fibers; often used as a finishing jacket over
thermal insulation for piping.

glass concrete A concrete slab or panel in
which individual translucent glass lenses have
been set, usually in a geometric pattern, to per-
mit passage of light.

glass cutter A hand tool used for scoring or
cutting glass; consists of a small, sharp wheel of
hardened steel which is set in a handle, or a tool
with a diamond point.

glass door A door of thick, heat-strengthened
or tempered glass; there are no rails or stiles.

glass fiber, glass fibre See fiberglass.

glass house 1. British term for greenhouse. 2.

A residence having exterior walls which are
almost completely glass; an outstanding example
is Philip Johnson's glass house in Connecticut.

glass paper A type of fine sandpaper, made
with powdered glass as the abrasive.

glass pipe A pipe fabricated from a low-expan-
sion borosilicate glass having a low alkali con-
tent; used primarily for the drainage of various
corrosive liquids; very brittle and therefore used
only where protection is provided against
mechanical damage to the pipe.

glass reinforced concrete Concrete that has
been reinforced by the addition of glass fibers to
the concrete mix.

glass seam A fracture in limestone that has
been recemented and annealed by deposition of
transparent calcite; limestone containing such a
seam is structurally sound.

glass silk Same as glass wool.

glass size The size of a piece of glass required
for glazing a given opening, allowing suitable
clearance between the edge of the glass and the
rebate.

glass slate Same as glass tile.

glass stop 1. A glazing bead. 2. A fitting which
holds the lower end of a patent glazing bar; pre-
vents the pane from sliding down.

glass surface coating 1. A coating applied to
a glass surface, usually to tint the glass a desired
color or to control the amount of solar radiation
that is transmitted through the glass. The coat-
ing may be applied as the molten glass passes
along a long continuous oven; alternatively, the
coating may result from dipping the glass into a
chemical solution, and then drying and firing it.

2. A metal coating evaporated on a surface while
it is under a vacuum.

glass tile, glass slate Tile fabricated of translu-
cent or transparent glass; installed in a roof sur-
face to allow light to enter the room below.

glass wool, glass silk Spun glass fibers in bulk
form; resembles wool; used as thermal insula-
tion, in air filters, and in fabricating fiberglass
blankets, boards, and tile. Also see mineral wool,
fiberglass.

glaze 1. A ceramic coating, usually thin, glossy,
and glass-like, formed on the surface of pottery,
earthenware, etc. 2. The material from which
the ceramic coating is made. 3. To install glass in
windows, doors, storefronts, curtain walls, and
various other segments of building construction.

glaze coat l.In built-up roofing having a
smooth surface, the top layer of asphalt. 2. A
temporary coating of bitumen used to protect
the plies of built-up roofing when the applica-
tion of the top pouring and surfacing is delayed.

3. A layer of thin, almost transparent, colored
paint which allows an undercoat to show
through.

glazed 1 . Said of an opening that is filled with
sheets of glass, as in a window. 2. Said of a finish
that is composed of ceramic materials fused into
its surface, usually making it essentially impervi-
ous to moisture.

glazed block A concrete block that has been
glazed on one side, thereby providing the side
with a smooth, hard surface; often colored.

glazed brick A brick that has been fired in a
kiln hot enough to fuse the clay and sand on its
surface, usually forming a dark glassy coating.

glazed door 1 . Any door that has top and bot-
tom rails and is glazed. 2. A French door.

463

glazed interior tile

glazed interior tile A glazed ceramic tile hav-
ing a body that is suitable for interior use, usually
nonvitreous; not fabricated for use under condi-
tions of excessive impact or of freezing and
thawing.

glazed tile Ceramic tile having a fused impervi-
ous glazed surface finish (clear, white, or col-
ored) composed of ceramic materials fused into
the body of the tile; the body may be nonvitre-
ous, semivitreous, or impervious.

glazed 'work Brickwork built with enameled
brick or glazed brick.

glazement A waterproof surfacing applied on a
masonry surface.

glazier's chisel A putty knife shaped like a
chisel, used in setting glass.

glazier's point, sprig A thin small three- or
four-cornered piece of sheet metal, used to hold
a pane of glass in a window frame while putty is
applied.

glazing clip A metal clip used to retain a pane
of glass in a metal frame while glazing compound
is applied.

PUTTY ROLL

GLAZIER'S POINT

glazier's point

glazier's putty A type of glazing compound.

Also see putty.
glazing 1. Setting glass in an opening. 2. The

glass surface of a glazed opening.
glazing bar One of the vertical or horizontal

bars within a window frame which hold the

panes of glass; a muntin.
glazing bead, glass stop l.Same as bead, 3.

2. At a glazed opening, removable trim that

holds the glass firmly in place.
glazing block Same as setting block,
glazing brad Same as glazier's point.

GL» ZING C04P0LWD

glazing clip

glazing color A transparent wash, used to

cover a ground coat of paint.
glazing compound A putty-like material

used to seal window glass in place; differs from

putty, 1 in that it retains its plasticity for an

extended period of time.

glazing fillet A small strip of wood used to hold
glass in a rebate; a glass stop.

glazing gasket A prefabricated strip of mate-
rial used to seal and secure glass, or sealed
glazing units, into frames and openings by a
dry glazing method without using compounds or
tapes.

glazing molding 1. A molding which serves as
a glazing fillet. 2. A glass stop, 2.

glazing point Same as glazier's point.

glazing rabbet, glazing rebate A rabbet, 3

that receives the glass in a window frame or glaz-
ing bar.

glazing size See glass size.

glazing spacer block One of a number of
blocks used to support glass in its frame.

glazing sprig, glazing brad A headless nail
used as a glazier's point to retain a pane of glass
in a wooden opening while the putty is soft.

glazing stop Same as glass stop.

glazing tape A ribbon of resilient material for
sealing a glass pane or panes in a frame, sash, or
opening.

glebe house An archaic term for parsonage.

gliding window Same as sliding sash.

global illuminance The sum of light from all
natural sources: direct, the sky, and ground-
reflected.

globe, light globe l.A transparent or diffus-
ing enclosure (usually of glass) to protect a light
source, to diffuse and redirect the light, or to

464

glue line

change the color of the light. 2. An incandes-
cent lamp.

globe valve A valve in which the flow of water
is controlled by a movable spindle which lowers
to a fixed seat, thereby restricting the flow
through the valve opening; the spindle is fitted
with a washer to provide tight closure; usually
enclosed in a chamber having a globular shape.

Stem

Sonnet

Wheel

Disc

globe valve

glory The luminous halo encircling the head of
a sacred person and the radiance or luminous
emanation encompassing the whole.

glory

gloss The degree of surface luster; ranges from a
matte surface practically without sheen to an
almost mirror-like glossy finish; intermediate

conditions (in increasing order of glossiness) are:
flat, eggshell, semigloss, and full gloss or high gloss.

glossing up The appearance of glossy areas in a
matte surface when it is fingered or rubbed. Also
see burnishing.

glossy paint A paint that dries with a superfi-
cial shine or luster, in contrast to a flat paint.

glow discharge An electric discharge in a gas
at low pressure which produces a diffuse glow;
characterized by a low cathode temperature, a
low current density, and a high voltage drop.

glow lamp A glow discharge lamp which gen-
erates light in an ionized gas close to the elec-
trodes; commonly used as an indicating device
because of the low power consumption.

glue Any fluid adhesive substance used for join-
ing materials, often of substantial weight; gener-
ally refers to adhesives that cure without heat:
animal glue, fish glue, emulsion glue, etc.

glue block, angle block A block of wood, set
into an interior angle formed by two boards, and
glued in place to strengthen the joint.

glue down As applied to carpet, the installa-
tion of the carpet backing by adhering it directly
to the flooring with an adhesive.

glued-laminated timber A manufactured
product consisting of four or more wood layers,
none of which exceeds 2 in. (5 cm) in thickness,
bonded together with adhesive; may be com-
prised of pieces which are end-joined to form
any desired length, or which may be glued edge-
to-edge to give greater width.

glue-laminated timber

glued-up stock Pieces of wood (including
veneer or furniture) joined together by gluing.

glue line The line of adhesive between two sur-
faces that are glued, as between plies in plywood.

465

glycerol

glycerol, glycerin, glycerine Colorless, odor-
less fluid used in mixing synthetic and natural
resins for paints and varnishes; used for making
distempers more pliable; used in the manufacture
of some adhesives.

glyph l.A V-shaped, vertically oriented
groove used as an ornament in the Classical
Revival style and its derivatives; usually found
on a Doric frieze, as in triglyph. 2. A sculptured
pictograph.

glyptic Pertaining to carving or engraving.

glyptotheca A sculpture gallery.

GM Abbr. for "grade marked."

gneiss A coarse-grained metamorphic rock hav-
ing discontinuous foliation; usually dark; com-
posed mainly of quartz, feldspar, mica, and
ferromagnesian minerals. Generally classed as
trade granite in the building stone industry.

goblet pulpit In a church, a pulpit on a central
support that is often hexagonal or circular in
section, similar to a goblet.

go»devil A device used to clean a pipeline by
placing it at the pump end of the pipeline and
forcing it through the pipe by water pressure.

godown In India and the Far East, a storehouse
of any description.

godroon See gadroon.

going (Brit. ) 1 . The horizontal distance between
two consecutive risers of a step. 2. Of a stair or
flight, the horizontal distance between the first
and last risers, i.e., the run.

going rod A rod used in laying out the going, 1
of a flight of steps.

gold bronze A powdered copper alloy used in
the manufacture of gold or bronze paint; usually
contains copper, zinc, lead, and tin.

golden section The division of a line into two
segments so that the ratio of the whole line to
the larger segment equals the ratio of larger seg-
ment to the smaller one; often called the golden
section. This ratio was once considered by some
as having an inherent aesthetic value.

gold foil See gold leaf.

gold leaf Very thin sheets of beaten or rolled
gold, used for gilding and inscribing on glass;
usually contains a very small percentage of cop-
per and silver. Sometimes heavy gold leaf is clas-
sified as gold foil.

gold size A varnish used to attach gold leaf or
foil to a surface; it turns sticky quickly on appli-
cation, and then sets slowly.

golosniki In early Russian architecture,
acoustic resonators, made of clay, which were set
into the upper portions of the walls of some
churches; the mouth of the resonator faced the
interior of the church and was flush with the
wall surface. Similar resonators have been found
in some Greek Orthodox and early Scandina-
vian churches.

gonge The Anglo-Saxon term for a privy.

gont A thin wood shingle, used for roofing in
early Russian architecture.

good morning stairs In a full Cape house, the
front stairs leading from the front hall to the attic
rooms; at the chimney block, the stairs turn both
right and left, serving both sides of the house.

goods lift In Britain, a service elevator.

goose neck 1. Any section of pipe, curved like
the neck of a goose, or in a U-shape; some-
times flexible. 2. In ductwork, an inverted
U-shaped duct section with a screened opening;
used for air intake or exhaust. 3. A curved sec-
tion of a handrail which forms its termination at
the top of a newel post.

gopuram In Hindu architecture, a tall monu-
mental gateway.

gore Same as lune.

gore lot A small triangular lot.

gorge 1 . In some orders of columnar architecture,
a narrow band around the shaft near the top, or
forming part of the capital near the bottom; a fillet
or narrow member which seems to divide the
capital from the shaft. 2. A cavetto or hollow
molding. 3. A narrow entry into a bastion.

gorge cornice Same as Egyptian gorge.

gorgerin See hypotrachelium.

gorgoneion In classical decoration, the mask
of a Gorgon, a woman with snakes for hair, to
avert evil influences.

gospel hall House for Protestant Christian
worship.

gospel side The left side of a church as one faces
the altar.

Gothic arch A loose term often denoting any
arch with a point at its apex, such as a lancet
arch.

466

Gothic Revival

Gothic architecture The architectural style
of the High Middle Ages in Western Europe,
which emerged from Romanesque and Byzan-
tine forms in France during the later 12th cent.

Gothic architecture showing construction of a Gothic

church, illustrating principles of isolated supports and

buttressing

Gothic architecture: Late type Gothic base, Rouen

11111=

f m ttti , i\l] \

Gothic architecture:

ult construction

Its great works are cathedrals, characterized by
the pointed arch, the rib vault, the development
of the exterior flying buttress, and the gradual
reduction of the walls to a system of richly deco-
rated fenestration. Gothic architecture lasted
until the 16th cent., when it was succeeded by
the classical forms of the Renaissance. In France
and Germany one speaks of the Early, High, and
Late Gothic; the French middle phase is referred
to as Rayonnant, the late phase as Flamboyant.
In English architecture the usual divisions are
Early English, Decorated, and Perpendicular.

Gothick See Neo-Gothic.

Gothic Revival A movement originating in the
18th century and culminating in the 19th century,
flourishing throughout Europe and the United
States, aimed at reviving the spirit and forms of
Gothic forms; applied to country cottages,
churches, some public buildings, and castlelike
structures. Gothic Revival buildings usually are
characterized by ashlar masonry, polychromed
brickwork, or wood walls, often extending into the
gables without interruption; Gothic motifs such as

Gothic architecture: Gothic pier

Gothic Revival: facade of house

467

Gothic sash

battlements, decorative brackets, finials, foils, foli-
ated ornaments, hood moldings, label moldings,
pinnacles, pointed arches, towers, turrets; often, a
porch with flattened Gothic or Tudor arches; a
symmetrical facade; steeply pitched gables often
decorated with ornate gingerbread bargeboards;
projecting eaves; decorative slate or shingle pat-
terns on the roof; occasionally, a flat roof with
crenelated and castellated parapets; ornamental
chimney stacks and chimney pots; a cast-iron dec-
orative strip at the ridge of the roof; windows
extending into the gables; often, an elaborately
paneled front door set into a lancet arch; the entry
door sometimes within a recessed porch or under a
door hood, occasionally bordered with sidelights.
The initial phase is sometimes called Early Gothic
Revival; the latter phase is sometimes called Late
Gothic Revival or Victorian Gothic. Also see Colle-
giate Gothic, High Victorian Gothic, and Carpen-
ter Gothic.

Gothic sash A term occasionally applied to a
lancet window.

Gothic survival The survival of Gothic forms
and construction techniques long after the
demise of Gothic architecture (for example, as
late as the 17th century); usually in a provincial
context, as distinct from Gothic Revival.

gouache l.A method of painting, using
opaque pigments pulverized in water and mixed
with gum. 2. A painting so made. 3. An opaque
color used in the process.

gouge 1 . A chisel with a longitudinal curved
blade, used to cut holes, channels, or grooves in
wood or stone. 2. A form of wear in resilient
floor coverings which is accompanied by
removal of material and penetration consider-
ably below the immediate floor surface.

gouge bit A bit shaped like a gouge, with the
piercing end sharpened to a semicircular edge for
shearing the fibers around the margin of the
hole; removes the wood almost as a solid core.

gouge slip, oilstone slip, slipstone A
shaped oilstone for sharpening gouges or shaped
chisels.

gouge 'work An ornamental wood surface hav-
ing decorative surface marks made with a chisel
whose blade is curved.

government anchor A type of steel anchor
which is inserted through a hole in the web of a

steel beam; used to anchor a wall-bearing beam
to masonry construction.
government house 1. Building for the offices
of the main departments of government, esp. in
English colonies or Commonwealth nations. 2.
Governor's state home, esp. in a Crown colony.

GOVT On drawings, abbr. for "government."

gpd Abbr. for "gallons per day."

gpm Abbr. for "gallons per minute."

gps Abbr. for "gallons per second."

GR On drawings, abbr. for "grade."

grab bar A hand grip, usually installed in a
shower, which may be used for steadying
oneself.

grab bar

grab bucket A clamshell.

grab crane A crane which is fitted with a
clamshell.

grab rail Same as grab bar.

grab set See flash set.

gradation See particle-size distribution.

grade 1. The classification of materials by qual-
ity. In lumber, plywood, and building boards, the
classification usually depends on the quality for
one face only. 2. The ground elevation or level,
contemplated or existing, at the outside walls of
a building, or elsewhere on the building site.
3. Rate of rise or fall of a roadway, often expressed
in feet per 100 ft, in meters per kilometer, or as a
percentage, ascending grades being plus, descend-
ing minus. 4. The slope of a line of pipe with
reference to the horizontal; usually expressed as
the fall in a fraction of an inch per foot (or cen-
timeters per meter) length of pipe. 5. The cut-off
elevation of a pile.

grade beam That part of a foundation system
(usually in a building without a basement)
which supports the exterior wall of the super-
structure; commonly designed as a beam which

468

grading curve

"WSjBmjWi^

■9 II -S^— GRADE BEAM
■ II. I

4 i!!

grade beam

bears directly on the column footings, or may be
self-supporting, as a long strap footing.

grade correction A correction applied to a
distance measured on a slope to reduce it to a
horizontal distance between the vertical lines
through its end points.

grade course The first course at grade level,
usually waterproofed with a damp check or damp
course.

graded aggregate Aggregate having a particle-
size distribution characterized by uniform grading.

graded sand Fine aggregate (diameter under
l A in., i.e., 6.4 mm) having a particle-size distri
bution characterized by uniform grading.

graded standard sand Ottawa sand, accu-
rately graded between the 600-ji (US Standard
No. 30) and 150-|I (No. 100) sieves; used in the
testing of cements. Also see Ottawa sand, stan-
dard sand.

grade hallway An enclosed passageway that
provides a protected path of escape in the event
of fire; terminates at a street or an open space or
court communicating with a street.

grade level The level of the surface of the
ground after the cut and fill process has been
completed.

grade line A line usually marked with stakes or
monuments, each having an elevation referred
to a common datum; by measurement or compu-
tation from such elevations and stakes, a grade is
established between the terminal points.

grade passageway Same as grade hallway.

grade plane A reference plane representing
the average of the ground level adjoining a
building at its exterior walls.

grader, towed grader A multipurpose ma-
chine used for leveling and crowning, mixing
and spreading, ditching and bank sloping, and
side casting material, or for light stripping oper-
ations; not intended for heavy excavation.

grader

grade ring A precast concrete ring at the top of
a manhole; used to adjust the top of the manhole
so that it is set at the proper angle.

grade school See elementary school.

grade slab A reinforced concrete slab, set
directly on the ground, which serves as the foun-
dation for the structure above.

grade stake In earthwork, a stake marking the
specified level.

grade strip A strip of wood which is nailed to
the inside of a concrete form to indicate the
upper line to which concrete is to be poured.

grade tto Same as annulet.

gradient 1 . The degree of inclination of a sur-
face, road, or pipe, often expressed as a percent-
age. 2. A rate of change in a variable quantity, as
temperature or pressure. 3. A curve representing
such a rate of change.

gradienter An attachment to an engineer's
transit with which an angle of inclination is
measured in terms of the tangent of the angle,
rather than in degrees and minutes.

gradinata The steps in a Classical amphitheater.

gradine 1 . A step. 2. A raised shelf above and at
the back of an altar.

grading l.The action of excavating or filling,
or a combination thereof. 2. See particle-size
distribution.

grading curve A graphical representation of
the proportions of different particle sizes in a
material; obtained by plotting the cumulative or
separate percentages of the material passing

469

grading plan

through sieves in which the aperture sizes form a
given series.

grading plan A plan which shows the pro-
posed finish of the ground surface of a given
site, usually by means of contours and grade
elevations.

grading rules Specifications by which lumber,
plywood, etc., are grouped according to quality.

grading timber The sorting of timber, logs, or
lumber according to the number and type of
defects.

graduated course One of a number of courses
of roofing slates that diminish in gauge from the
eaves to the ridge.

graecostasis In the Roman Forum, a platform
where the ambassadors from foreign states stood
to hear debates and attend ceremonies.

graffito Casual remark or depiction drawn on a
wall; not synonymous with sgraffito.

graft To join a scion, shoot, or bud to the stock
of another similar plant.

grain l.The direction, arrangement, or appear-
ance of the fibers in wood, or the strata in stone,
slate, etc. 2. The easiest cleavage direction in a
stone. 3. Any small, hard particle, as of sand.
4. A unit of weight measure in the English sys-
tem of units; 7,000 grains equals 1 lb; used as a
measure of the weight of moisture in air.

graining Simulating a grain such as wood or
marble on a painted surface by applying a
translucent stain, then working it into suitable
patterns with tools such as graining combs,
brushes, and rags. See false woodgraining, faux
bois, woodgraining.

grain size A measure of the size of mineral
particles of soil or rock; a physical characteris-
tic of the particles of a soil which affects its
mechanical properties; used in classification
and identification.

grain slope The angle of grain in a piece of
lumber relative to a line parallel to its length.
The angle for structural timber (as for beams) is
restricted to a slant of 1 part in 8.

granary A storehouse for grain, usually after it
has been threshed, or for the storage of corn after
it has been husked.

grandmaster key A key that operates locks in
several groups, each of which has its own master
key.

grandstand A structure, often with a roof, which
supports standing or seated spectators at a race-
course, ball field, stadium, or similar public places.

grand tier The tier immediately above the
parterre in an opera house, theater, etc.

grange l.A farm. 2. A farmhouse and its out-
buildings.

granite 1 . An igneous rock having crystals or
grains of visible size; consists mainly of quartz,
feldspar, and mica or other colored minerals.
2. In the building stone industry, a crystalline
silicate rock having visible grains; this includes
gneiss and igneous rocks that are not granite in
the strict sense.

graniteware A one-coat porcelain-enameled
article having a mottled pattern which is pro-
duced by the controlled corrosion of the metal
base prior to firing.

granitic finish A finish provided by a face mix
of granolithic concrete.

granolithic concrete Concrete suitable for
use as a wearing surface finish for a floor; made of
cement mixed with specially selected aggregate
(originally granite chips) of suitable hardness,
surface texture, and particle shape.

granolithic finish A surface layer of grano-
lithic concrete which may be laid on a base of
either fresh or hardened concrete.

granular-fill insulation A loose-fill ther-
mal insulation, such as vermiculite or perlite,
in the form of granules, pellets, nodules, pow-
der, or flakes; can be poured or placed by hand
without mechanical means. Also see loose-fill
insulation.

granular material Gravels, sands, or silts
which exhibit no characteristics of cohesiveness
or plasticity; more permeable than cohesive or
plastic soils.

granular soil Soil comprised of sediments or
other unconsolidated accumulations of particles
(such as gravel, sand, or silt) having no clay con-
tent; crumbles easily when dry.

granulated blast-furnace slag The non-
metallic product consisting essentially of sili-
cates and aluminosilicates of calcium which is
developed simultaneously with iron in a blast
furnace and is granulated by quenching the
molten material in water or in water, steam, and
air. Also see blast-furnace slag.

470

gravity-type refuse chute

granulated cork Small particles of cork used
as loose-fill thermal insulation, to make cork
tile, etc.

grapevine joint See scribed joint, 2.

grapevine ornament A running ornament
usually consisting of a grapevine with bunches of
grapes and grape leaves.

graphics The art of drawing, esp. of drawing
according to mathematical rules, as in perspec-
tive, projection, etc., associated with architec-
tural and engineering plans.

graphite, plumbago One of the forms under
which carbon occurs in nature; electrically
conductive; in powdered form, used as a lubri-
cant.

graphite paint A painting compound consist-
ing of powdered graphite and oil; used to coat
metallic structures to inhibit corrosion.

grapple A clamshell, 2 which has three or more
jaws; especially suitable for handling rocks such
as rip rap.

grappler A pointed spike that is driven into
masonry to provide an eye for support of the
brackets of a scaffold.

grass cloth, China grass cloth A loosely
woven fabric of vegetable fibers; used for wall
covering.

grass house Any primitive house built of nat-
ural materials such as grass, reeds, or fronds; usu-
ally having a round or rectangular shape and a
thatched roof; examples include palma hut and a
Hawaiian hale.

grass table Same as ground table.

grassed waterway A grass-surfaced channel
for water, usually used to carry away surface
runoff and reduce surface erosion.

grate A surface with suitable openings to sup-
port a fuel bed, such as coal, and permit passage
of air through the burning fuel. Designed to
permit removal of unburned residue, and may be
horizontal or inclined, stationary or movable.

grating l.A grate; also see coke grating. 2. A
grille. 3. Same as grillage. 4. See bar-type grat-
ing. 5. See plank-type grating.

gravel A coarse granular aggregate, larger than
sand; formed either naturally or by crushing
rock; will pass a 76.1-mm (3-in.) sieve and be
retained on a 4-76-mm (No. 4) sieve.

gravel board, gravel plank A board attached
near the lower edge of a wood fencing so that the
fencing does not touch the ground; prevents the
lower end of the fencing from rotting.

graveling-in The spreading of gravel on top of
a flood coat, 2 in built-up roofing.

gravel plank See gravel board.

gravel roofing See built-up roofing.

gravel stop, gravel strip, slag strip A flange,
usually of a metal strip, used to prevent gravel or
loose surfacing from washing off a roof; may also
provide a finished edge for built-up roofing.

gravel stop

grave trap On a theater stage, an oblong trap, 2
often located toward the front of the stage along
its center line.

gravitational water Same as free water, 2.

gravity convection The transfer of heat
resulting from differences in density of air or
water (because of differences in temperature),
that thereby causes the flow of air or water.

gravity drainage system See building grav-
ity drainage system.

gravity feed Said of a chute that transports
waste materials, soiled linen, etc., from one level
of a building to another by the force of gravity.

gravity flow The flow of water drawn through
a conduit under the force of gravity.

gravity hinge A hinge that closes automati-
cally as a result of the weight of a door to which
it is attached.

gravity main See building gravity drainage
system.

gravity supply, gravity water system A
water system in which the source of water is at a
higher elevation than the place where the water
is to be used. (See illustration p. 472.)

gravity-type refuse chute A refuse chute in
which waste material is conveyed down the chute
by the force of gravity. (See illustration p. 472.)

471

gravity wall

Gravity tank

GROUND SURFACE

Supply from

water main

Water
distribution"

system

Static
head

House pumps

gravity supply

tsSSIfiW

gravity wall

gravity water system See gravity supply.

gravity water tank, gravity tank A water
storage tank in which water is stored at atmo-
spheric pressure and distributed by gravity flow in
a downfeed system; the tank is usually elevated
above the roof of a building and is filled by a
house pump.

Chute

Joint

Automatic
sprinkler

Floor frame
(floor support)

Intake
door

Throat

Discharge
door

Discharge — p- -£?'
opening

gravity-type refuse chute

gravity wall A massive concrete wall that
resists overturning by virtue of its own weight.

Low-water
alarn

Domestic water
outlet

To domestic water
distribution system

Supply Emergency overflow outlet

gravity water tanks

gravel roofing See built-up roofing.
gray cast-iron pipe See cast-iron pipe.

gray scale A series of achromatic samples in
discrete steps in lightness from white to black.

gray water Waste water which may be a combi-
nation of liquid and water-carried wastes, with
the exception of human wastes.

472

Greek Revival style

Roof of tank

Steel
reinforcing

hoop

I tank
gravity water tanks

grazing light Light that is reflected from a
source placed close to a surface, usually to
emphasize the texture of the surface.

gre See grees.

grease extractor Equipment which traps
droplets of grease and greasy vapors from the
exhaust air of cooking equipment.

grease interceptor See grease trap.

grease trap, grease interceptor A device for
removing grease from waste water by allowing
the retained liquid to cool and the grease to
solidify; then the grease is separated by flotation;
it rises to the top of the trap, where it is held.

Vant

Outlet

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liiiT^sas!

fr"^j Air ri \>: :

, Inlet

"Baffle ;;

■ ... f

Removable \

M grease q
batkfcl ■;

■ A_W&ter
8 level

SSSSSSE

great chamber A chamber within the great
room of a manor house.

great house The main or central residence of
an estate or plantation.

great room The main room of a house of some
pretension; usually the room largest in size.

great tower See keep.

grece Same as grees.

Grecian style A 19th-century term for Greek
Revival style.

Greek cross A cross with four equal arms.

Greek key See fret.

Greek masonry See isodomum.

Greek Revival style An architectural style
based on the reuse of ancient Greek forms in
architecture. Public buildings in this style were
usually symmetrical in plan and rectangular in
shape. Buildings in this style are commonly char-
acterized by: asymmetrical plan, a symmetric
front-gabled facade with a classical pedimented
portico extending across the building; a facade of
brick, clapboard, or stone construction; a partial-
height porch, sometimes with the porch roof hav-
ing a raked cornice supported on round or square
columns with ornamental capitals; pilasters; a
frieze or a plain wide band of trim with a simple
architrave below a heavy cornice; walls that imi-
tate flat stonework, wood buildings often painted
white; typically sparse ornamentation, including
classical Greek decorative motifs; gabled or
hipped roof; widely spaced double-hung windows
trimmed with decorative crowns; a wide, imposing
entry way, framed by pilasters or engaged columns;
an entry door usually having raised panels with a
horizontal line of small lights above the door; a
vertical line of small lights on each side of the
door. In America, during the height of its wide-
spread popularity from about 1820 to the 1850s,
Greek Revival was frequently called the National
Style. Also see Classical Revival style and Neo-
classical style.

grease trap

Greek Revival style

473

Greek theater

Greek theater An open-air theater con-
structed by the ancient Greeks; usually built on a
hillside, with no outside facade. The orchestra, 1,
on which the actors and chorus performed, was a
full circle; behind it was the skene, a temporary
or permanent building for the actors' use. In the
classic theater, the seating area (around and fac-
ing the orchestra) usually occupied approx.
three -fifths of a circle. Also see Roman theater.

i*f«U'i

Greek theater: o, orchestra; I, logeion; £>, parascenium;
sk, skene; st, stoa

green 1 . See green concrete. 2. See green lumber.
3. See green mortar. 4. See undercuring. 5. An

open space or public park in the center of a town
or village. 6. A bowling green or putting green.
green architecture Architecture in which
the design is focused on making a building
energy-efficient, so as to reduce its energy con-
sumption, water consumption, operating costs,
and environmental impact. Such efficiencies
include the maximal use of natural lighting,
low-e glass, solar electric systems, energy-efficient
lighting systems, energy-efficient ventilation
systems including the use of the chimney effect,
and newer sustainable materials and techniques
that minimize heat loss in buildings.

greenbelt A wide area of parks, farmland, or
undeveloped land surrounding a community.

green concrete Concrete which has set but

not appreciably hardened.
green glass A low-grade glass which is green
because of impurities in its raw materials.

greenheart A British Guiana hardwood having
high density and strength; difficult to machine;
used for piles, planks, etc., where strength is
important.

greenhouse, glasshouse A glass-enclosed,
heated structure for growing plants and out-of-
season fruits and vegetables under regulated,

protected conditions. Also see conservatory,
hothouse, orangery.

green lumber Lumber which has not been
dried or seasoned.

green manure Green herbaceous plants
plowed under to benefit the soil.

green mortar Mortar that has set but yet not
dried.

green room A lounge near the stage of a the-
ater or concert hall where actors or musicians
may rest or receive visitors before or after a per-
formance.

green timber Freshly converted timber that
has not been dried in a kiln; has a high moisture
content, usually well above 50%.

greensand A resin used to oxidize the soluble
iron in water and then to filter it out.

greenstone A basic igneous rock having a
green color due to iron-bearing silicate minerals;
quarried and fabricated for structural and deco-
rative dimension stone.

greensward Turf, green with grass, usually
well-tended.

grees, gre, greese, gryse In medieval archi-
tecture, a step or flight of steps.

G/Rfg, G/R Abbr. for "grooved roofing."

grid 1. See gridiron. 2. See grillage. 3. In survey-
ing, closely-spaced reference lines which are per-
pendicular to each other; elevations usually are
taken at the intersections of these lines.

grid bearing The angle in the plane of the pro-
jection between a line and a north-south grid
line.

grid ceiling A ceiling with apertures through
which natural or artificial light can pass.

grid foundation A combined footing which is
formed by a number of intersecting con-
tinuous footings, loaded at their points of inter-
section; the area covered is less than 75% of the
total area within the outer limits of the assembly.

gridiron A framework (usually of steel) over a
theater stage and immediately below the stage-
house roof; used as the structural support from
which scenery and lighting equipment are hung.
Also called a grid.

grid plan A city plan in which the streets are
laid out in a rectangular pattern of lines forming
rectangles of uniform size.

474

grisaille glass

grid pulley, grid sheave A pulley, located on
a gridiron, through which a cable or rope of a rig-
ging system passes.

grid sheet system A system of soldier beams

and horizontal sheeting used to brace the lateral
face of a deep excavation or cut; the soldier
beams receive lateral support from wales and
braces.

grid system See exposed suspension system.

griffe See spur, 1.

griffin, griffon, gryphon A mythological
beast having a lion's body with an eagle's head
and wings; used decoratively.

grillage 1. A framework of heavy timbers, steel,
or reinforced concrete beams laid longitudinally
and crossed by similar members laid upon them
to spread a heavy load over a larger area, esp. for
use where the ground is not firm. 2. A series of
steel beams, bolted together and placed over a
footing; used to distribute a concentrated col-
umn load over the top of the footing.

J^,

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r ■[!■■■ Il :

ii- i [ - -■ i r - 1

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j -U

grillage, 2

grille 1 . A grating or openwork barrier, usually
of metal but sometimes of wood, stone, or rein-
forced concrete; used to cover, conceal, deco-
rate, or protect an opening, as in a wall, floor, or
outdoor paving. 2. A louvered or perforated cov-
ering for an air passage opening, which can be
located in the wall, ceiling, or floor.

grille, 1

grillroom, Brit, grille room A room for infor-
mal dining in a restaurant, club, or hotel.

grillwork Material which functions as, or has
the appearance of, a grille.

grinder pump A special type of solids-handling
pump, designed to grind sewage solids into a fine
slurry.

grindstone A rotating solid stone wheel (usu-
ally sandstone) used for grinding, shaping, sharp-
ening, or polishing.

grinning through l.The visible appearance
of lathing through a plaster coat. 2. The visible
appearance of an undercoat of paint through a
topcoat.

grip l.Of a mechanical fastener: the thickness
of the material or parts which the fastener is
designed to secure when assembled. 2. Of a rivet:
the thickness of the plates or parts through
which the rivet passes. 3. A channel that carries
away rain water from a foundation, during its
construction.

Q »« — P".]

h-CHIP — *t

grip, 2

grip handrail A handrail having a diameter
which is especially easy to grasp; often has a roll
molding along its upper surface.

grip length See bond length, development
length.

grisaille 1. A system of painting in grey tints of
various shades; used either for decoration or to
represent objects, as in relief. 2. A stained glass
window executed according to this method.

grisaille glass 1. A white glass coating that
produces an opalescent effect. 2. Glasswork

475

gristmill

having a light grey monotone color, often with
an enameled pattern.

gristmill A mill for grinding grain; in earlier
times powered by the wind, a stream, river, or by
tidal water.

grit A granular abrasive material (e.g., con-
sisting of particles of aluminum oxide or silicon
carbide) which is used to coat cloth, paper, or
wheels for sanding, grinding, or polishing; also
used to provide a nonslip finish to a surface.

gritblast See sandblast.

grit trap Same as catch basin.

grizzly A stationary screen or series of equally
spaced parallel bars set at an angle; used to
remove oversize particles in processing aggregate
or similar material.

grizzly brick Same as salmon brick.

grnd Abbr. for ground.

grog A crushed refractory material such as
crushed firebrick or crushed pottery; used in the
manufacture of products designed to withstand
extreme heat.

groin The ridge, edge, or curved line formed by
the intersection of the surfaces of two intersect-
ing vaults.

groins: A

groin arch, groined arch One arched divi-
sion of cross vaulting.

groin centering l.In groining without ribs,
the centering of timber extended during con-
struction under the whole surface. 2. In ribbed
or groined work, the centering for the stone
ribs, which need support until their arches are
closed, after which the supports for the filling
of the spandrils are sustained by the ribs them-
selves.

groined 1. Having groins. 2. Showing the
curved lines resulting from the intersection of
two semicylinders or arches.

groined rib A rib under the curve of a groin,
either to mask the groin or to support it.

groined rib: A shows an enlarged section

groined vault, groin vault A compound
vault in which barrel vaults intersect, forming
arrises called groins.

groined vault

groining Any system of vaulting implying the

intersection, at any angle, of simple vaults.
groin rib See groined rib.
groin vault Same as groined vault.

grommet A metal or plastic eyelet which pro-
vides a reinforced hole for attachment.

grommet

476

gross wall area

groove A long narrow cut in the edge or face of
a wood member; a groove across the grain is a
dado; one parallel with the grain is a plow.

grooved joint A joint used to connect two
steel pipes or ductile-iron pipes; employs an
inner elastomeric gasket and an outer split-
metallic sleeve with an integral bolt for tighten-
ing the assembly.

Split ring

metallic coupling

Elastomeric gasket
Grooved pipe

grooved joint

grooved seam A seam in which the edges of
two metal sheets are bent approximately 180°,
inserted in each other, flattened, and then
locked by pressure.

grooved seam

groove joint A construction joint formed by a
groove in a floor slab, wall, or pavement; used to
control random cracking.

groover A tool used to form grooves in a con-
crete slab before hardening; used to control
crack locations or provide patterns.

groove weld A weld made in a preformed
groove between two members to be joined.

TOE OF WELO V
FACE OF WELO
TOE OF WELO

TOE OF WELO

groove weld

grooving plane A plane, 1 used in carpentry,

esp. to cut grooves in wood.
gross area, gross cross-sectional area Of

a concrete masonry unit, the total area of a
section perpendicular to the direction of the
load, including areas within the cells of the
unit and within reentrant spaces, unless these
spaces are occupied by portions of adjacent
masonry.

gross building area The total area of a build-
ing; usually expressed in square feet or square
meters.

gross density of housing The maximum
number of dwelling units allowed per unit area
under applicable zoning regulations; often
expressed in dwellings per acre or dwellings per
hectare.

gross floor area The area within the perimeter
of the outside walls of a building as measured
from the inside surface of the exterior walls, with
no deduction for hallways, stairs, closets, thick-
ness of walls, columns, or other interior features;
used in determining the required number of exits
or in determining occupancy classification. Also
see net floor area.

gross leasable area The total floor area
designed for tenant occupancy and tenant use.

gross lease A lease in which the owner receives
the contractual rent out of which he or she must
pay all or most of the operating expenses of the
real estate.

gross load In heating, the net load plus
allowances for piping losses and for pickup.

gross output The available number of Btu at a
boiler outlet nozzle for satisfying the gross load
continuously, while the boiler is operating under
applicable code limitations.

gross section Of a structural member, the total
area of the cross section, making no deductions
for holes within the cross section.

gross volume 1. In a revolving-drum concrete
mixer, the total interior volume of the revolving
portion of the mixer drum. 2. In an open-top
mixer, the total volume of the trough, assuming
that no vertical dimension of the container
exceeds twice the radius of the circular section
below the axis of the central shaft.

gross 'wall area The area of a wall including any
openings, such as doors or windows, in the wall.

477

grotesque

grotesque Sculptured or painted ornament
involving fanciful distortions of human and ani-
mal forms, sometimes combined with plant
motifs, esp. a variety of arabesque which has no
counterpart in nature.

grotto A natural or artificial cave, often deco-
rated with shells or stones and incorporating
waterfalls or fountains.

ground 1. A nailing strip fixed in a masonry or
concrete wall as a means of attaching wood trim
or furring strips; also called a common ground,
rough ground, fixing, fixing fillet, fixing slip. 2. A
plaster ground. 3. The side of an electric circuit
connected to the earth, used as a common return.

ground, 2

ground anchor A device used to secure a
structure from lateral or vertical forces.

ground bar An electrical conductor which
forms a common junction for a number of
ground conductors.

ground beam 1. A groundsill. 2. A horizontal
heavy timber or reinforced concrete beam at or
near ground level for distributing a load which it
supports.

ground brush An oval or round paintbrush
used for covering large areas.

ground bus A bus to which grounds, 3 from
individual pieces of equipment are connected;
the bus, in turn, is connected to the ground at
one or more points.

ground casing The blind casing of a window.

ground coat 1. A first coat of paint or enamel,
particularly when designed to show through a
topcoat. 2. A porcelain enamel applied directly
to the base metal to function as an intermediate
layer between the metal and the cover coat.

ground conductor An electrical conductor
which provides an electrical connection between

(a) the frame of a piece of equipment or part of a
system and (b) a ground bar or ground electrode.

ground course The horizontal base course of
masonry on the ground.

ground cover l.Low planting, often mainte-
nance-free, used in masses. 2. A thin plastic
sheet, or the like, spread over the ground in a
crawl space to minimize moisture penetration.

grounded Said of an electrical device, piece of
equipment, or electrical system that is connected
to the earth or to some extended electrically con-
ducting body that serves as the earth, whether
the connection is intentional or accidental.

grounded conductor An electric system
or circuit conductor which is intentionally
grounded.

grounded system A system of electric con-
ductors in which at least one conductor is inten-
tionally grounded, either solidly or through a
current-limiting device.

grounded work Joinery, such as a chair rail,
which is attached to a metal or wood ground.

ground electrode An electrical conductor (or
group of conductors) in intimate contact with
the ground; used to provide an effective electri-
cal connection with the ground.

ground-faced block A concrete block whose
exposed surfaces are ground smooth.

ground fault l.An electrical short-circuit
involving one or more phase conductors and
ground. 2. An insulation fault between a con-
ductor and ground or the frame of a device.

ground fault circuit interrupter (GFCI)
A type of ground fault protection in areas where

ground fault circuit interrupter

478

ground plate

personnel are at high risk of receiving electrical
shocks (for example, in damp locations); makes
use of a device designed to trip at a ground cur-
rent in the milliampere range, i.e., very much
below currents that are normally harmful.

ground fault protection Protection against
short'Circuits produced by ground faults; may be
provided by circuit breakers, relays, or ground
fault circuit interrupters.

ground fill See fill, 1.

ground floor The floor of a building which is
nearest the surrounding surface of the ground;
usually the first floor in the US but sometimes a
floor between a basement or cellar and the first
floor.

ground glass Glass having a surface that has
been roughened, usually by sandblasting or by
acid, to make it nontransparent.

grounding conductor A conductor used to
connect electric equipment or the grounded cir-
cuit of an electric wiring system to a grounding
electrode or electrodes.

grounding electrode A conductor embedded
in the earth, used to maintain ground potential
on the conductors connected to it.

grounding electrode conductor The elec-
trical conductor used to connect the grounding
electrode to the equipment grounding conduc-
tor and/or the grounded conductor of the circuit
at the service equipment.

grounding outlet An electric oudet which is
equipped with a receptacle of the polarity type
with an additional contact for the connection of
an equipment grounding conductor.

grounding plug, grounding-type plug A
plug, 5 having a blade which provides a ground
connection for an electric device.

grounding system A system of intercon-
nected grounds, 3.

ground investigation Same as site investiga-
tion. Also see geotechnical investigation.

ground joint l.A closely fitted joint in
masonry, usually without mortar. 2. A machined
metal joint which fits tightly without packing or
a gasket.

ground joist A joist which rests on sleepers
laid on the ground, stones, or dwarf walls; used
in basements or ground floors.

ground-key faucet A faucet through which
flow is controlled by a slightly tapered plug with
a hole in it; when the faucet is on, the fluid flows
through the hole; when the plug is turned
through 90°, the flow is stopped.

ground-key valve A valve which controls fluid
flow in a manner similar to a ground-key faucet.

-GROUNDING BLADE
grounding plug

ground-key valve

ground lease A legal contract for the lease of
land; contains an agreement that the lessee is
obligated to pay rent each year for the use of the
land for the duration of the contract; the lessee
usually builds on the land but the buildings so
constructed must be turned over to the land's
owner at the termination of the contract.

ground level See ground line.

ground light Visible radiation from the sun
and sky which is reflected by surfaces below the
plane of the horizon.

ground line The level of the surface of the
ground, above (or below) which the height of a
structure (or depth of excavation) is measured.

ground niche A niche whose base is on a level
with the floor.

ground plan, ground plot The plan of a

building taken at ground level.

ground plane The horizontal plane of projec-
tion in a perspective drawing; the horizontal
plane upon which the object in the drawing rests.

ground plate A groundsill.

479

ground rent

ground rent The legally-contracted rent paid
annually according to the terms of a ground
lease.

ground ring A bare copper wire, laid under-
ground in the shape of a loop around the exte-
rior of a building; at the corners of the building
and other appropriate locations, ground rods are
installed and connected to the loop.

ground rod A metal rod or pipe which is
driven into the ground to provide an electrical
connection to the earth. Usually, the deeper the
rod is driven beneath the earth's surface, the
lower its electric resistance to ground.

groundsel Same as groundsill.

ground sign A sign supported by uprights or
braces in or upon the surface of the ground.

groundsill, ground beam, ground plate,
mudsill, sole plate In a framed struc-
ture, the sill which is nearest the ground or
on the ground; used to distribute concen-
trated loads.

ground story Same as ground floor.

ground table, earth table, grass table A

projecting course or plinth resting immediately

upon the foundation; the lowest course visible

above the ground.
ground wall The foundation wall of a building.
groundwater Water, near the surface of the

ground, which passes through the subsoil.

groundwater

groundwater level At a particular site, the
level below which the subsoil and rock masses of
the earth are fully saturated with water.

groundwater recharge See recharge.

ground wire l.A conductor leading to an
electric connection to the earth. 2. A wire used
to establish line and grade, as in shotcrete work;
usually of small-gauge, high-strength steel.

groundwork Batten strips applied over roofing
boards or the like; used as a base for the applica-
tion of roofing materials.

grouped columns Three or more closely spaced
columns forming a group, often on one pedestal.

grouped pilasters Three or more closely spaced
pilasters forming a group, often on one pedestal.

group house, row house One of an unbro-
ken line of houses having a common wall or
party wall with its neighbors.

group relamping Replacing all lamps in a light-
ing system at one time. Also see spot relamping.

group vent In plumbing, a branch vent that
serves two or more traps.

grout 1. Mortar containing a considerable
amount of water so that it has the consistency of
a viscous liquid, permitting it to be poured or
pumped into joints, spaces, and cracks within
masonry walls and floors, between pieces of
ceramic clay, slate, and floor tile, and into the
joints between preformed roof deck units. 2. In
foundation work, mixtures of cement, cement-
sand, clay, or chemicals; used to fill voids in
granular soils, usually by a process of successive
injection through drilled holes.

grouted-aggregate concrete Concrete that
is formed by injecting grout into previously
placed coarse aggregate.

grouted frame A hollow-metal doorframe
which is completely filled with cement or mortar.

grouted masonry 1. Concrete masonry con-
struction composed of hollow units where the
hollow cells are filled with grout. 2. Multi-withe
construction in which space between withes is
solidly filled with grout.

grouting Filling the voids in or between aggre-
gate, block, or tile with grout.

grouting sand Sand which passes through an
841(0. (No. 20) sieve, and not more than 5%
through a 74|l (No. 200) sieve.

480

guide pile

grout pumping The placement of a liquid-like
grout under pressure.

grout slope The natural slope assumed by fluid
grout when injected into preplaced-aggregate
concrete.

growth rate Rate of wood growth expressed as
the number of annual rings per inch measured
from pith to bark; sometimes used to rate soft-
woods for strength.

growth ring See annual ring.

grozing iron A hot iron used by plumbers for
finishing soldered joints.

grub To clear a site by removing roots, stumps,
and the like.

grub axe A tool for digging up roots or shrubs;
a mattock.

grub saw A handsaw used for cutting stone,
such as marble, into slabs for shelves, mantel-
pieces, etc.

grub screw See setscrew, 1.

grummet Same as grommet.

grundscheier A barn constructed by early
German-speaking immigrants to America; of
varied construction, depending on available
materials and the terrain; usually built on
slightly sloping ground. See German barn.

gryphon A griffin.

gryse See grees.

GSA Abbr. for "General Services Administra-
tion."

guarantee 1 . A legally enforceable assurance of
the quality or duration of a product or of work, 1
performed. 2. A binding commitment by one
person that another will perform his contract
obligations satisfactorily.

guaranteed maximum cost An amount
established in an agreement between owner
and contractor as the maximum cost of per-
forming specified work on the basis of cost of
labor and materials plus overhead expense and
profit.

guaranty bonds l.See bid bond. 2. See labor
and material payment bond. 3. See performance
bond. 4. See surety bond.

guard bar Any bar serving as a protection or a
means of security, as a window bar, 3 or window
guard, 2.

guard bead 1 . A corner bead. 2 . A staff bead.

guard board A raised timber at the edge of a
scaffold that prevents workers or tools from
dropping off the edge of the platform.

clip to fix a guard board to a scaffold

guarded Enclosed, fenced, covered, shielded, or
otherwise protected, by means of suitable barri-
ers, rails, screens, covers or casings, mats, or plat-
forms, to prevent dangerous contact.

guard rail For an automatically operated door,
a railing used to separate and control traffic pass-
ing in opposite directions through the door.

guard post Same as bollard.

guardrail system A protective railing system
along the outer edges of locations of an accessi-
ble roof, balcony, landing, platform, or ramp.

guard system A system of building components
located near the open sides of elevated walking
surfaces, designed to minimize the possibility of
an accidental fall from the walking surface.

gudgeon A metal pin used to hold together two
blocks or slabs, as of stone.

guesthouse l.A separate residence for guests,
as a house on a private estate or a boarding house
of high standards. 2. A monastery building
specifically for receiving visitors.

guest room l.In a multiple-family dwelling,
a room occupied or intended to be occupied
for hire. 2. In a single-family or two-family
dwelling, a room in the main or an accessory
building occupied or intended to be occupied
by nonpaying guests.

guglia An elongated finial.

guide bead Same as inside stop.

guide coat A thin coat of paint which high-
lights the bumps or imperfections in a sealer or
filler beneath, and thus serves as a guide for rub-
bing them down.

guide pile A heavy, square timber which is
driven vertically downward to guide steel sheet-
piling.

481

guide rail

guide rail A track that acts as a guide for a slid-
ing window or door.

guide wire In a theater stagehouse: l.A steel
cable which guides the vertical movement of a
curtain. 2. A line which guides the movement of
a counterweight arbor.

guildhall A place of assembly for a society of
craftsmen or merchants for their mutual assis-
tance; an outgrowth of similar medieval organi-
zations or guilds.

guilloche An ornament formed by two or more
bands twisted over each other in a continuous
series, leaving circular openings which are often
filled with round ornaments.

guilloche

guillotine Same as bench trimmer,
guillotine window Same as double-hung
window.

gula l.A molding having a large hollow. 2. A
cyma. 3. A gorge.

gulbishche In early Russian architecture, a ter-
race which surrounds a building.

gullet The concave space between saw teeth.

gulley, gully In a drainage system, a fitting at
the upper end of a drain that receives the dis-
charge from waste pipes or rain water.

gum 1 . A moderately high-density hardwood of
the eastern and southern US; whitish to gray-
green in color and of uniform texture; used for
low-grade veneer, plywood, and rough cabinet
work. 2. Any of a class of colloidal substances
that are soluble or swell in water, exuded by or
prepared from plants; sticky when moist.

gum arabic, acacia, gum acacia A white,
powdery, water-soluble gum, extracted from cer-
tain acacia trees; used in the manufacture of
adhesives and transparent paints.

gum bloom A defect in a painted surface,
appearing as a lack of gloss or a haze, resulting
from the use of incorrect reducer.

gumbo A fine-grained clay; very sticky
when wet.

gum pocket See gum vein.

gum rosin See rosin.

gum seam In a piece of lumber, a check or
shake filled with gum.

gum streak See gum vein.

gum vein, gum pocket, gum streak In
hardwoods, a local accumulation or streak of
resin.

gumwood Wood of the gum tree, esp. eucalyp-
tus; used for interior trim.

gun 1. See spray gun. 2. A pressure cylinder for
delivering freshly mixed concrete pneumati-
cally. 3. Shotcrete material delivery equipment;
also see shotcrete gun.

gun consistency See gun grade.

gun finish A layer of shotcrete as it is applied,
without subsequent hand finishing.

gun grade, gun consistency A grade of
caulking or glazing compound which has the
proper softness for application by a caulking
gun.

gun hole, gun loop, gun port, gun slot A
type of embrasure in a structure designed to
provide protection in case of enemy attack; the
opening enables a defender to fire through a
wall, over a wide angle.

Gunite A proprietary name for shotcrete.

gunning Applying material, e.g., shotcrete,
with the use of a gun.

gun pattern The outline of material which is
discharged by a gun, as in a shotcrete operation.

gunshot house Same as shotgun house.

gun-stock post Same as musket-stock post.

gunstock stile A diminished stile in which
there is a gradual change in width between the
broader and narrower parts.

Gunter's chain A measuring device in land
surveying, consisting of 100 metal links, equiva-
lent to 66 ft in length.

gusset, gusset plate A plate, usually triangu-
lar in shape, used to connect two or more mem-
bers, or to add strength to a framework.

482

gymnasium

gutta (pi. guttae) In Classical architecture,
one of a number of pendant ornaments in a rect-
angular arrangement; each gutta is shaped like
an inverted frustum of a cone, i.e., a cone in
which the upper tip has been lopped off; usually
found on the underside of the mutules of a Doric
entablature.

IkikL

gutta: Top, guttae attached to mutules;
bottom, detail showing guttae

guttae band Same as regula in the Greek Doric
entablature.

gutter 1. A shallow channel of metal or wood
set immediately below and along the eaves of a
building to catch and carry off rainwater from
the roof. Also see box gutter, concealed gutter,
flying gutter, standing gutter, sunk gutter,
through gutter. Also called eaves gutter, eaves
trough, roof gutter. 2. In electrical wiring, the
space provided at the sides, top, or bottom
within an electric panel or switchboard to permit

TAL
ajTTEfi

gutter, 1

the installation of feeder and branch wiring
conductors.

gutter bearer A member to which gutter
boards are fixed.

gutter bed A sheet of flexible metal, over the
wall side of a gutter along the eaves, which pre-
vents overflow from penetrating the wall.

gutter board, gutter plank In a wood gutter
along the eaves of a roof, a board on which the
lining material of the gutter is laid.

guttered A term sometimes used to describe a
structural framing member (such as a corner
post) that is either encased or cut away to dis-
guise its appearance.

gutter hook A light metal strap used to secure

or support a metal gutter.
gutter plate 1 . One of the sides of a box gutter.

2. A beam which supports a lead gutter.

gutter spout Same as downspout.

gutter tool A tool used to give the desired
shape and finish to concrete gutters.

guy A supporting rope, cable, or wire which is
anchored at one end and tied to an object or
structure in order to stabilize it.

guy anchor A buried object used to secure a
guy

guy derrick A derrick comprised of a boom
and a mast supported by wire rope guys.

GV Symbol for gate valve.

gymmer See gemel.

gymnasium l.A large room or building
devoted to physical education or indoor games.
In addition to the playing floor, the building
form usually contains staff offices, locker and
shower rooms, and spectator facilities. 2. In con-
tinental Europe, a secondary school which pre-
pares students for university. 3. In Greek and
Roman architecture, a large open court for exer-
cise, surrounded by colonnades and rooms for
massage, lectures, etc.; a palaestra, ephebeion.

483

gynaeceum

gynaeceum That part of a Greek house or a

church reserved for women.
GYP On drawings, abbr. for gypsum.
gypsite Gypsum having a purity of from 60 to

90% and containing clay, loam, and sand.
gypsum A soft mineral consisting of a hydrated

calcium sulfate from which gypsum plaster is

made (by heating); colorless when pure; used as

a retarder in portland cement.

gypsum backerboard A gypsum board used
as a base on which to adhere tile or gypsum wall-
board; similar to, but less smooth than, wall-
board; is surfaced with a grayish paper.

gypsum block, gypsum tile, partition tile
1. A hollow or solid building block, fabricated of
gypsum; used in a nonbearing partition; serves as
a base for plastering. 2. A cast gypsum building
block.

gypsum board A wallboard having a gypsum
core. This noncombustible core has a paper
surface.

STUD

GYPSUM
BOARD

TAPERED EDGE

JOINT CEMENT
TAPE

—JOINT CEMENT
— FEATHER EDGE

gypsum board: detail showing joint treatment

gypsum cement See Keene's cement.

gypsum concrete A mixture of a calcined
gypsum binder and wood chips or other aggre-
gate; when mixed with water, sets to a con-
glomerate mass; used for poured gypsum roof
decks.

gypsum core board A gypsum board consist-
ing of either a single board or factory laminated
multiple boards for use as a gypsum stud or core
in semisolid or solid gypsum board partitions;
usually available in thicknesses from 3 /4 inch
(19.0 mm) to 1 inch (25.4 mm).

gypsum fiber concrete Gypsum concrete in
which the aggregate consists of shavings, fiber,
or chips of wood.

gypsum formboard A gypsum board used as a
permanent form for pouring gypsum roof decks.

gypsum insulation Gypsum in pellet form
used as loose-fill thermal insulation.

gypsum lath, board lath, gypsum plaster-
board, rock lath A base for plaster; a sheet
having a gypsum core, faced with paper, which
provides a good bond for plaster; usually manu-
factured in 16-in. by 48-in. (40.6-cm by 121.9-
cm) or 24-in. by 96-in. (61.0-cm by 243.8-cm)
panels, Vb or Vi in. (0.95 or 1.27 cm) thick with
round or square edges.

gypsum-lath nail A low-carbon steel nail
having a large flat head and a long diamond
point; esp. used to fix gypsum lath and plaster-
board.

<£

^W^WW

gypsum-lath nail

gypsum molding plaster A calcined gypsum
plaster used primarily for plaster casts or molds;
occasionally used for gauging plaster.

gypsum mortar A plastic mixture of gypsum,
water, and often sand; can be troweled in the
plastic state; hardens in place when the water it
contains evaporates.

gypsum neat plaster A calcined gypsum
plaster without an aggregate, often used as a base
coat.

gypsum panel A wallboard having a gypsum
core.

gypsum perlite plaster A gypsum base-coat
plaster containing perlite as an aggregate.

gypsum plank 1 . British term for gypsum lath.
2. A lightweight, fire-resistant, structural pre-
cast roof deck having a gypsum core reinforced
with galvanized-steel mesh.

!HS

gypsum wallboard

gypsum plaster Ground gypsum that has been
calcined and then mixed with various additives
to control its setting and working qualities; used,
with the addition of aggregate and water, for
base-coat plaster.

gypsum plasterboard See gypsum lath.

gypsum sheathing A wallboard having a gyp-
sum water-repellent core; surfaced with a water-
repellent paper; usually 2 or 4 ft (61 or 122 cm)
wide, 8 ft (243.8 cm) long, and Vi in. (1.27 cm)
thick; used as a base for exterior wall coverings.

gypsum tile l.A cast gypsum building unit.
2. See gypsum block.

gypsum trowel finish Various proprietary,
factory-mixed plasters used as a finish coat,
containing mainly gypsum which has been cal-
cined.

gypsum vermiculite plaster Gypsum base-
coat plaster containing vermiculite as an
aggregate.

gypsum wallboard A gypsum board used pri-
marily as an interior surfacing in a building.

485

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KH On drawings, abbr. for "quarter-hard."

Vii\ On drawings, abbr. for "half-hard."

H On drawings, abbr. for "hard."

h Symbol for "hour."

H&M In the lumber industry, abbr. for "hit and
miss."

habit, habit of growth The distinctive appear-
ance and pattern of growth of a plant.

habitable area The gross floor area of an occu-
pied dwelling, not including the basement,
garage, or crawl spaces.

habitable room A space used for living, sleep-
ing, eating, or cooking, or combinations thereof,
but not including bathrooms, closets, halls, stor-
age rooms, utility and similar spaces.

habitable space By code, a space occupied by
one or more persons for living, sleeping, eating,
or cooking (although a kitchenette is not usually
deemed to be a habitable space). Compare with
nonhabitable space.

habitacle l.A dwelling or habitation. 2. A
niche for a statue.

HABS Abbr. for Historic American Buildings
Survey.

hachure One of a series of parallel lines drawn
on topographic maps in the direction of the
slopes of hills or depressions to indicate relief
features. The steeper the slopes, the heavier and
more closely spaced the hachures become.

hacienda 1. A large estate in North and South
American areas once under Spanish influence.

2. The main house on such an estate or ranch.
hacking 1. Roughening a surface by striking

with a tool. 2. Laying brick so that the bottom
edge is set in from the plane surface of the wall.

3. In a stone wall, the breaking of one course of
stone into courses of different height.

hacking knife , hacking-out tool A knife used
to remove old putty from a frame before reglazing.

hacksaw A saw having a blade (typically fine-
toothed) which is supported in an adjustable
metal frame; used for cutting metals.

hafner ware In northern European decorative
arts of the Renaissance and derivatives, mod-
eled, lead-glazed earthenware often used for tiled
heating stoves.

haft The handle of a tool.

hagiasterium A sacred place; a baptismal font.

hagioscope Asquint, 1.

ha»ha A barrier in the form of a trench; usually
used to prevent livestock from crossing; a
sunken fence.

HAIA Abbr. for "Honorary Member, American
Institute of Architects."

haikal The central chapel of the three forming
the sanctuary of a Coptic church.

hair beater A tool formerly used by plasterers
to remove hair or fiber from plaster; made of two
pieces of wood lath, fastened at one end by wire.

hair checking Same as hairline cracking.

hair cracking See hairline cracking.

hair felt A non-woven felt usually made of cattle
hair; once used as thermal insulation in buildings.

haired mortar Mortar containing hair or fiber.

hair hook A tool now obsolete, having several
tines for mixing hair or fiber into plaster.

hair interceptor, hair trap A device used to
remove hair before it enters a drainage system.

Outlet

Body

Strainer

hair interceptor

487

hairline cracking

hairline cracking, hair cracking, plastic
shrink-age cracks Very fine cracks, in a ran-
dom pattern, which usually do not completely pen-
etrate a paint film, an exposed layer of concrete, etc.

hairline joint Between two abutting members,
a joint not more than %4 in. (0.38 mm) wide.

hair mortar A mortar (traditionally) contain-
ing a mixture of cow's hair, lime, and sand.

hairpin l.The wedge used to tighten some
types of form ties. 2. A hairpin-shaped anchor
set in place while concrete is plastic.

hale In Hawaii, a primitive house, especially
one consisting of a wood framework covered by
thatched grass.

half baluster An engaged baluster, projecting
about half of its diameter.

half baluster

half-bastion Same as demi-bastion,
half bat, half brick, snap header

cut to half its length.

A brick

half bat

— V

half bath A room containing a wash basin and

toilet (W.C.).
half-blind dovetail Same as lapped dovetail.
half bond Same as stretcher bond.
half-brick wall A wall having a thickness equal

to the thickness of a brick laid as a stretcher.
half Cape house A Cape Cod house that has

two double-hung windows on only one side of

the front door.

half column An engaged column projecting
approx. one half its diameter, usually slightly more.

half columns

half-cut notch A simple joint between the
timbers at a corner of a log house; formed by cut-
ting away the lower half of the end of one timber
and placing it over and at right angles to another
timber in which the upper half of the end has
been cut away; a spike or treenail is usually
driven through the two ends to secure the joint.

half -cut notch

half door The lower half of a Dutch door.

half dovetail A wood joint similar to a dovetail

but having only one side flared; the other side is
straight.
half-dovetail notch At a corner of a log
house, a notch in the shape of a half dovetail at

the end of a rectangular exterior timber; forms
an interlocking joint when mated with an

488

half-span roof

half-dovetail notch

appropriately notched timber at right angles to
it; compare with dovetail notch.

half-dugout A primitive shelter, often tempo-
rary, having a significant portion of its structure
dug below ground level; commonly has sod walls
and a sod roof; also see sod house.

half figure Same as terminal figure.

half-gabled Descriptive of a shed roof having
the shape of a flat inclined plane.

half-glass door A door having glass in the
panel above the lock rail.

half hatchet A tool similar to a lath hammer
but with a broader blade.

half header A brick, or cement block, either
cut longitudinally into two equal parts or cut into
four parts by cutting these halves transversely;
used to close the work at the end of a course.

half header

half-hipped roof Same as gambrel roof.

half house A Cape Cod house or saltbox hav-
ing two windows on one side of the front door
and none on the other.

half landing Same as halfpace.

half-lap joint, halved joint, halving joint
A joint at the intersection of two wood members
of equal thickness in which half the thickness of
each is removed so that they fit together to form
a flush surface.

half -lap joint

half-lattice girder See Warren truss.

half-moon A roughly crescent-shaped fortifi-
cation outwork. Also see ravelin.

half-mortise hinge A hinge, one plate of
which is mortised in the door leaf, the other
being surface -mounted on the jamb leaf.

halfpace, half-space landing A stair land-
ing at the junction of two flights which reverses
the direction of horizontal progress, making a
turn of 180°. Such a landing extends the width
of both flights plus the well.

halfpace stair A stair making a 180° turn, usu-
ally having a halfpace landing.

half-pitch roof A roof having a pitch of 45°.

half principal A roof member or rafter that
does not reach to the ridgepole but is supported
at its upper end by a purlin.

half- relief Same as mezzo-relievo.

half-ripsaw A handsaw similar to a ripsaw, but
with teeth that are more closely spaced.

half-round gutter A gutter, 1 having a half-
round cross-section.

half round, half-round molding A convex
strip or molding of semicircular profile.

half round

half-round file A file whose cross section is
convex on one face and flat on the other face.

half-shaft A roll molding on each side of an
opening such as a window.

half slating Same as open slating.

half-space landing See halfpace.

half-space stair Same as halfpace stair.

half-span roof A lean-to roof.

489

half story

half story A story within a sloping roof; usually
having dormer windows and occupying about
half the area of the floor or floors below. Also see
garret, attic.

half S-trap In plumbing, same as P-trap.

half-surface hinge A hinge which is applied
to the surface of the door leaf and to a mortised
jamb leaf.

half timber A piece of timber measuring not
less than 5 in. by 10 in. (12.7 cm by 25.4 cm) in
cross section.

half-timbered Descriptive of buildings of the
16th and 17th cent, which were built with
strong timber foundations, supports, knees, and
studs, and whose walls were filled in with plaster
or masonry materials such as brick.

half-timbered

half-timbered construction Building con-
struction in which all supporting and bracing
members are heavy timbers as in the medieval
system of braced timber framing of a house; to
provide additional rigidity and better thermal
insulation, the space between the structural tim-
bers is usually filled with brick or filled with plas-
ter, wattle-and-daub, or a nogging consisting of
clay (often taken from the cellar excavation)
mixed with chopped straw to act as a binder.
Also see columbage, fachwerk, false half-
timbering, pierotage.

half truss A jack truss whose shape is half that
of a normal roof truss; partly supported by a main
roof truss and at an angle to it.

half-turn Descriptive of a stair which turns
180° or through two right angles at each land-
ing. Also see dogleg stair.

halide lamp See metal halide lamp.

halide torch A test device for detecting halo-
carbon refrigerant leaks; usually uses alcohol and

burns with a blue flame; when the sampling tube
on the tester draws in refrigerant vapor, this is
indicated by a change in color of the flame.

hall l.The main room of a medieval or post-
medieval house that served as the center of family
life, usually combining the functions of a kitchen,
dining room, living room, and workroom for
activities such as spinning, sewing, and candle
making; often called a keeping room; also see
hall-and-parlor plan. 2. An imposing entrance
hall; also called a living hall. 3. A large room for
assembly, entertainment, and the like. 4. A small,
relatively primitive dwelling having a one-room
plan. 5. A manor house. 6. A corridor.

hall-and-parlor plan A common two-room
floor plan in early colonial New England; the
front door opened into a small vestibule, called a
porch, which contained two interior doors lead-
ing to the two rooms of the house. One room,
the hall, 1 , served as the center of activity for the
entire family; the other room, the parlor, con-
tained the best furniture, as well as a bed for the
parents. These rooms were separated by a wall
containing a massive chimney that served them
both. A loft space above was reached by a stair-
way in the hall. Also see center-hall plan.

^■mT —

r _^^^k_ hall

£w*

hall-and-parlor plan

hall bedroom A bedroom having the same
width as the hall, formed by sectioning off one
end of the hall.

hall chamber A bedroom directly above a hall, 1 .

hall church A church having aisles, no
clerestory, and an interior of approximately uni-
form height.

hall keep A rectangular keep in which the
great hall and bed chamber were adjacent.

hallway A corridor; a passageway.

halogen lamp See tungsten-halogen lamp.

490

hance arch

halon extinguishing system A fire protection
system employing halon gas as the means of extin-
guishing a fire used in areas of high monetary
value, but now of limited application because of
environmental concerns about the use of this gas.

halved-and-lapped notch Same as half-cut
notch.

halved-faced Same as fair-faced.

halved joint A half-lap joint.

halved splice Same as half-lap joint.

halving The cutting away of two wood mem-
bers at their ends, each to half its thickness;
when the two cut surfaces are placed together, a
lap joint or half-lap joint is obtained.

halving joint A half-lap joint.

hammam An establishment for bathing in the
Oriental way, with steam rooms, etc.; a Turkish
bath.

hammer A hand tool having a head at right
angles to the handle; used for driving nails,
pounding, flattening materials, etc.

hammer-beam roof A roof supported by
hammer beams.

NECK

-ACE
hammer: nomenclature

hammer ax A lath hammer.

hammer beam One of a pair of short horizon-
tal members attached to the foot of a principal
rafter in a roof, in place of a tie beam.

hammer-beam

roof

hammer beam: A

hammer brace A bracket under a hammer
beam to support it.

hammer-dressed Said of stone masonry
which has been shaped and brought to a rela-
tively smooth finish by means of a hammer only.

hammer drill A percussive-type pneumati-
cally powered rock drill.

hammered glass Translucent glass made by
embossing rolled glass on one side to resemble
beaten metal.

hammer finish A paint finish which appears
to have been applied over hammered metal; pro-
duced by the use of nonleafing metallic pigment
plus tinting pigments which are mixed in a spe-
cial binder.

hammerhead crane A heavy-duty jib crane
with a counterbalance, giving it a T-shaped
appearance.

hammerheaded Said of a chisel which is to be
struck with a hammer, rather than a mallet.

hammerhead key See double-dovetail key.

hammer post A pendant which is in the shape
of a pilaster; serves as an impost for a hammer
brace.

Hamm tip A type of nozzle for a gun which
delivers shotcrete; has a larger diameter at
the midpoint than at either the inlet or the outlet.

hance The curve of shorter radius which
adjoins the impost at each side of a three- or
four-centered arch.

hance arch Same as hanse arch.

491

hand

hand 1 . The direction, left or right, of the swing
of a door (when viewed from the side usually
considered the outside) or associated doorframes
or hardware. A left-hand door has hinges on the
left and the door swings away; a left-hand
reverse door swings toward the viewer. A right-
hand door has hinges on the right and swings
away. A right-hand reverse door swings toward
the viewer. 2. Of a spiral stair, designates the
direction of turn of the stair. Right-hand refers to
a stair on which the user turns clockwise as he
descends. Left-hand refers to a stair on which
the user turns counter-clockwise as he descends.

hand brace Same as brace, 3.

hand clamp Same as screw clamp.

hand-dressed stone Same as dressed stone.

hand drill A hand-driven drill, 1.

hand elevator A very small elevator driven by
manual power, once used to carry written com-
munications and light goods between floors.

hand file See file.

hand float A wooden tool used to fill in and
float a plaster surface; used to produce a level
base coat or a textured finish coat.

handhole Same as a manhole, except that it is
smaller in size; often located at the termination
of an underground service entrance.

handicap accessibility See Americans with
Disabilities Act (ADA).

hand level A hand-held surveying instrument
used for rough checks of elevations and leveling
work, usually limited in use to a radius of 200 ft
(approx. 60 m) from an established elevation.
Consists of a metal sighting tube (but no tele-
scope) in which a spirit level is observed oppo-
site the horizontal cross hair.

hand line A line used to hand-operate a coun-
terweight, curtain, or other component in the
rigging system of a theater stage.

handling reinforcement The reinforcement
of a product that is required or desirable to prevent
its damage during its moving, handling, unload-
ing, and storage, prior to its final installation.

handling rope Same as hand line.

hand plate See push plate.

handrail Same as rail, 1,2.

handrail bolt, joint bolt, rail bolt A metal
rod with threads and a nut at each end; used to
bolt together two mating surfaces in a butt joint.

handrail height The vertical distance between
the upper surface of a top rail and the finish floor.

handrailing l.Same as handrail. 2. Handrail
construction which includes the provision of
handrail scrolls about landings and winders.

handrail scroll A spiral handrail end.

handrail wreath Same as handrail scroll.

handsaw Any hand-held saw for cutting wood
having a handle at one end; operated manually.

BLADE

TOE

HEEL

hand:

saw: nomenc

lature

hand screw Same as screw clamp,
hand snips Same as tin snips.
hand-wrought nail See wrought nail.

hangar A shed or shelter, particularly a struc-
ture for the shelter, service, and repair of aircraft.

hanger l.A wire, strap, or rod attached to an
overhead structure, used to support a pipe, con-
duit, the framework of a suspended ceiling, or the
like. 2. A U-shaped, stirrup-like bracket used to
support the end of a beam or joist at a masonry

hanger, 1

492

hanging stile

hanger, 2

wall or girder. 3. Any device used to suspend one
item or object from another item or object.
hanger bolt A bolt having a machine-bolt
thread on one end and a tapered lag-screw thread
on the other; used in heavy timber construction.

hanger bolt

hanging 1 . The mounting of a door on its frame
on hinges. 2. The mounting of an operable win-
dow sash in its frame.

hanging buttress In later Gothic architecture
and derivatives, a freestanding vertical rib or
buttress which is supported from a wall by a cor-
bel rather than by its own foundation.

hanging gable A small extension of the roof
structure beyond the end wall, at the gable end
of a barn or house; usually located at the ridge;
encloses a heavy beam that supports the rigging
used to hoist materials to upper stories.

hanging gutter A metal gutter which is hung
from the eaves of a roof by metal ties, sometimes
with support from the fascia.

hanging jamb That part of a doorframe to
which the hinges are attached.

hanging pew A pew raised on posts and usu-
ally set apart from the less prestigious seating,
accessed by a private stair.

hanging post The post on which a gate or door
is hung.

hanging rail The rail of a door to which a
hinge is fastened.

hanging sash A hung sash.

hanging scaffold A scaffold that is suspended
by ropes and pulleys.

hanging shingling Shingling on vertical or
near-vertical slopes.

hanging stair, hanging step 1. A stone step
cantilevered from the wall and free at the other
end. 2. See cantilever steps.

hanging step A step usually constructed with-
out a continuous carriage, 1 for support; instead
the steps are bolted together so that each step
provides support for the one above and the one
below; used, for example, in architecture of the
Shakers, a religious sect of English origin that
settled in America in the late 18th century.

hanging stile See hinge stile.

hanging gable

hanging stile

493

hanse arch

hanse arch, haunch arch An arch having a
crown of different curvature than the haunches,
which are thus strongly marked; usually a basket-
handle or three-centered or four-centered arch.

hard asphalt Solid asphalt having a normal
penetration, 2 of less than 10.

hardboard A building material manufactured
of wood fiber compressed into sheets; used
extensively in building, e.g., as interior panels or
durable siding.

hard-burnt Nearly vitrified; said of clay prod-
uct which has been fired at a high temperature;
usually has relatively low absorption and high
compressive strength.

hard-burnt brick, hard-fired brick A clay
unit that has been molded to the desired shape
and then treated in a kiln at a high temperature
to increase its mechanical strength, moisture
resistance, and weather resistance. See brick.

hard-burnt plaster Same as Keene's cement.

hard compact soil According to OSHA: all
earth materials not classified as running or
unstable.

hard-dry Descriptive of a stage of dryness of a
paint film when hard twisting pressure of the
thumb will not mar the surface. It is then ready
for service, rubbing, or application of a topcoat.

hardened glass Same as tempered glass.

hardener 1. A chemical (including certain flu-
osilicates or sodium silicate) applied to concrete
floors to reduce wear and dusting. 2. A material
added to a paint or varnish vehicle to increase
the gum or resin content, or to increase rate of
oxidation, so as to cause an increase in hardness
of the drying film. 3. The chemical component
in a two-component coating or adhesive which
causes the resin component to harden.

hard finish A finish coat consisting of gypsum
plaster and lime troweled to a smooth, hard,
dense finish.

hard-finish plaster Same as Martin's cement.

hard gloss paint A high-gloss enamel, formu-
lated with a hard-drying resin vehicle.

hard lead See antimonial lead.

hard light Light which produces well-defined
shadows.

hardness l.The resistance of wood, rubber,
sealant, plastic, or metal to plastic deformation by
compression or indentation; in wood, hardness is

generally related to density. Common methods of
measurement include the Rockwell, Brinell, Scle-
roscope, and Vickers tests. 2. A property of a paint
or varnish film that is a measure of its ability to
withstand damage from marring, abrasion, etc.
3. The degree of hardness, applied to water, based
on the amount of calcium and magnesium salts in
the water, expressed as grains per gallon or parts per
million of calcium carbonate. 4. See Mohs' scale.

hard oil A hard-drying interior oil or varnish.

hardpan An extremely dense hard layer of soil,
boulder clay, or gravel; difficult to excavate.

hard pine Same as yellow pine.

hard plaster, gauging plaster, molding plas-
ter A quick-setting plaster to which retarder has
been added to control set; used in the finish coat.

hard rock Rock, which is found during excava-
tion, that can be removed only by pneumatic
tools or explosives.

hard solder Any solder having a melting point
above solders alloyed of lead and tin, e.g., silver
solder or aluminum solder; applied with a braz-
ing torch.

hard steel 1. Steel that has undergone the
process of hardening. 2. Same as high steel.

hard-top A hard-surfaced road.

hardwall A type of gypsum neat plaster; used as
a base coat.

hardware Metal products used in construction,
such as: bolts, nails, screws (see rough hard-
ware); fittings, such as catches, hinges, locks,
etc. (see finish hardware); tools.

hardware cloth Steel wire-woven screening;
usually has a mesh Vs to % in. (3.18 to 9.53 mm);
commonly galvanized.

hard water Water containing solutions of min-
eral salts (sulfates of calcium and magnesium,
carbonates, and bicarbonates). Also see water
softener.

hardwood l.A tree belonging to the angio-
sperms; usually broad-leaved and deciduous, such
as cherry, mahogany, maple, oak, etc. 2. Wood
cut from such trees.

hardwood dimension stock A hardwood

stock that has been processed so that maximum

waste is retained at the mill.
hardwood strip flooring Same as strip flooring.
harl, harling Same as rock dash.

494

haunched mortise-and-tenon joint

harling Same as rough cast.

harmonic A component of a sound containing
more than one frequency which is an integral
multiple of the lowest frequency.

harped tendons Same as deflected tendons.

harsh mixture A concrete mixture which
lacks desired workability and consistency owing
to a deficiency of mortar or aggregate fines.

harsh mortar Mortar that is difficult to spread.

Hartford loop, Underwriters' loop An
arrangement of the return piping connections to
a steam boiler; used to balance pressures
between the supply and return sides of the boiler
and thus prevent boiler water from backing out
of the boiler and into the return.

hasp A fastening device consisting of a loop and
a slotted hinge plate, normally secured with a
padlock.

hasp

hastarium In ancient Rome, a room in which
sales were made by public auction, under public
authority.

hatch An opening, equipped with an openable
cover, in a roof or floor of a building for passage
of people or goods from one level to another or
for ventilation.

hatched molding Same as notched molding.

hatchet A combination chopping and driving
tool which has a wooden handle and a steel
head, with a hammer face and a blade which is
notched for pulling nails.

hatchet

hatchet door Same as Dutch door.

hatchet iron A plumber's soldering iron hav-
ing a bit which is shaped like a hatchet.

hatchway See roof hatch.

Hathoric, Hathor-headed Pertaining to
an Egyptian column with a capital which
bears masks of the Egyptian cow-head goddess
Hathor.

Hathoric capital A column whose capital
bears masks of the Egyptian cowhead goddess
Hathor. Occasionally found in Egyptian Revival.

hathpace Same as halfpace.

haul, haul distance l.The distance that an
excavated material is moved from the cut to the
fill. 2. The distance along the most practical
route for trucks to carry excavated material from
its center of mass to the center of mass of the fill.

haunch 1. The middle part between the crown
and the springing of an arch. 2. The part of a
beam projecting beneath a roof slab or floor.
3. That portion of a pipe barrel extending from
the bottom to the springline. 4. The lower third
of the circumference of a pipe. 5. The deepened
section of a beam near a support.

haunch: A, haunches of an arch

haunch arch See hanse arch.

haunch board One of the boards on both sides
of a form for a concrete girder.

HAUNCH
BOARDS

ch bo

haunched beam A beam whose cross section

thickens toward its supports.
haunched mortise-and-tenon joint A joint

between two members, formed by fitting a

495

haunched tenon

haunched tenon at the end of one of the mem-
bers into a corresponding mortise in the other.
haunched tenon A tenon, part of which has a
smaller width than the full width of the wood
member on which it is formed.

haunched tenon

haunching 1. Placing bedding material around
the haunch of a pipe. 2. The concrete support
at the sides of a drain or sewer pipe above the
bedding.

hautepace, hautpace Same as halfpace.

haw-haw Same as ha-ha.

hawk A flat piece of metal or wood used by
plasterers to carry plaster or mortar; held by a
wooden handle on the underside.

hawkbill snips Tin snips having a curved jaw
which is shaped to facilitate cutting along a curve.

hawksbeak A beak molding, 2 .

hawksbell Same as ballflower.

hayband A straw rope.

hay barrack An open-sided structure for storing
an overflow of hay from the main barn; usually
had a four- or five-cornered roof that could move
up on poles as the hay was packed beneath it.

hay barrack

haydite A lightweight aggregate, used in con-
crete, having an expanded cellular structure;
produced by heating shale.

hay hood Same as hanging gable.

hayloft The upper part of a barn in which hay is
stored.

hazard assessment An evaluation of the
environmental dangers to which a site may be
subject, such as earthquakes, flooding, torna-
does, and hurricanes.

hazard of contents The relative danger of fire
starting and spreading, of smoke or gases being
generated, of explosion or other occurrences
which potentially endanger the lives and safety
of the occupants of a building or structure.

hazardous area 1. Within a building, an area
which houses highly combustible, highly flam-
mable, or explosive products or materials which
are likely to burn with extreme rapidity or which
may produce poisonous fumes or gases, including
highly toxic or noxious alkalies, acids, or other
liquids or chemicals, which involve flame, fume,
explosive, poisonous, or irritant hazards. 2. Any
area in which there are fine particles or dust sub-
ject to explosion or spontaneous combustion.

hazardous substance A substance which, by
reason of being explosive, flammable, poisonous,
corrosive, oxidizing, or otherwise harmful, is
likely to cause death or injury.

haze Dullness of a paint film resulting from for-
mation of very fine surface imperfections.

HB 1 . Abbr. for "hollowback." 2 . Abbr. for hose
bib.

H»bar A steel bar shaped like an H; used in
structural systems; one form of main runner in a
suspended acoustical ceiling.

H'beam A steel beam shaped like an H.

H»block A hollow concrete masonry unit having
both ends open in the form of one-half of a cell.

H»brick Horizontally perforated brick.

HD On drawings, abbr. for head.

H/D ratio The ratio of the height H, to the
diameter D.

HDW On drawings, abbr. for "hardware."

hdwd. Abbr. for hardwood.

head 1 . In general, the top or upper member of
any structure; the top or end (esp. the more
prominent end) of a piece or member. 2. The

496

header joist

upper horizontal cross member, between the
jambs, which forms the top of a door or window
frame; may provide structural support for con-
struction above if required, as a doorhead or win-
dow head. 3. A stone that has one end dressed to
match the face because the end will be exposed at
a corner or in a reveal. 4. A roofing tile of half the
usual length but of the same width; for forming
the first course at the eaves. 5. See static head.

headache ball See breaker ball.

head casing The horizontal casing, 1 across the
top of a window or door opening.

header 1 . A masonry unit, laid so that its ends
are exposed, overlapping two or more adjacent
withes of masonry and tying them together; a
bondstone; a bonder. 2. A header joist. 3. A
framing member which crosses and supports the
ends of joists, rafters, etc., transferring the
weight of the latter to parallel joists, rafters,
etc. 4. In plumbing, a pipe having many out-
lets which are parallel and frequently at 90° to
the center line of the pipe. 5. A chamber into
which a number of pipes open. 6. A platform
header. 7. A transverse raceway for electrical
conductors which provides access to a cellular
floor, thereby permitting the convenient
installation of electrical conductors. 8. The
structural member immediately over a door
opening.

header block A concrete masonry unit having
a portion of one face shell removed to facilitate
bonding with adjacent masonry such as brick
facings.

header bond A pattern of brickwork consist-
ing entirely of headers, 1; usually, each course of
headers is displaced by half the width of one
header with respect to the headers in the course
above and the course below.

header course, heading course In masonry,
a continuous course of headers.

header duct A main duct or feeder duct for
bringing electrical cable from a service closet to
distribution ducts.

header»high Having the height of a masonry
wall to the first header course.

header joist, header, lintel, trimmer joist

A short structural member (as used in framing
an opening) which is fastened between parallel
full-length framing members at right angles to

header, 1

header, 3

□□□□□□□□□a
□□□□□□□□□a
□□□□□□□□□□

header bond

header duct

497

header tile

headi

eader joist

them and supports cut-off members, e.g., the
common joists in framing around a rectangular
opening in a wood floor. Also see tail piece.

header tile Tile containing recesses for brick
headers in masonry-faced walls.

head flashing The flashing installed in a mas-
onry wall over a window opening or projection.

HEAD JAMB

head jamb

head flashing

head guard Cavity flashing over a window or
door frame.

heading l.Same as upsetting. 2. A classifica-
tion of related data used in the AI A filing system
(Part Two of the uniform system) as the first step
in subdividing each of the sixteen divisions and
corresponding generally to the sections used in
Parts One and Three.

heading bond Same as header bond.

heading chisel See mortise chisel.

heading course In masonry, a course consist-
ing entirely of headers; a header course.

heading joint 1 . A joint between two pieces of
timber which are joined in a straight line, end to
end. 2. A masonry joint formed between two
stones in the same course.

head jamb, yoke The horizontal member
forming the top of a door opening; a doorhead.

head joint, cross joint The vertical mortar
joint between ends of masonry units.

headlap In the lapping of roofing shingles, the
shortest distance between (a) the lower edge of
an overlapping shingle and (b) the upper edge of
the lapped unit in the second course below.

head lining The lining at the head of a door
opening.

head loss Same as pressure drop.

headmold, dripstone, head molding, hood-
mold, weather molding The molding car-
ried around or over the head of a door or window.

head nailing The nailing of slates through
holes near the heads of the slates.

head piece 1. The capping piece of a series of
upright timbers. 2. The uppermost horizontal
member of a wood partition.

head plate Same as wall plate.

headroom, headway l.The clear vertical
space (as from floor to ceiling), esp. the height
which is available for passage. 2. In the stage-
house of a theater, the clear height over the
gridiron.

headstock A supporting beam for a church bell.

headstone The principal stone in a founda-
tion, as the cornerstone of a building or the key-
stone of an arch.

head stop Same as label stop, 1.

head up To remove the lower branches from a
tree or large shrub.

498

heat

headwall A masonry or concrete retaining wall

at the outlet of a drain.
headway Same as headroom.

headwork The heads and other ornaments on

the keystone of an arch.
healing The outermost layer of the roof of a

building.

healing stone A roofing slate or roofing tile.

hearse 1. A framework of metal bars or rods
placed over a tomb or coffin of a noble or very
important person. 2. A canopy, usually of
openwork or trellis, set over a bier, or more
rarely over a permanent tomb; used especially
to support candles, lighted at times of cere-
mony.

hearse

heart The center portion of a log, usually refer-
ring to heartwood or duramen.
heart and dart See leaf and dart.

heart bond In masonry, a bond, 6 in a masonry
wall, in which two headers meet in the middle of
the wall and another header covers the joint
between them.

heart-face boards Boards which are sawn so
that the face side is free of sapwood.

hearth l.The floor of a fireplace (usually brick,
tile, or stone) together with an adjacent area of
fireproof material. 2. An area permanently
floored with fireproof material beneath and sur-
rounding a stove.

hearthstone 1 . A single large stone forming
the floor of a fireplace. 2. Materials such as fire-
brick, fireclay products, concrete, etc., used to
form a hearth.

hearth trimmer See trimmer.

hearting Masonry forming the interior of a
wall, pier, etc., as distinguished from facework.

heart plank See centerplank.

hearth

heart shake A radial crack originating at the
heart of a log; usually results from improper sea-
soning.

heart shake

heartwood, duramen Wood at the core of an
exogenous tree; normally darker and much more
durable than sapwood.

heartwood

heat The form of energy that is transferred by
virtue of a temperature difference between two
bodies, the transfer being from the warmer to
the cooler body.

499

heat-absorbing glass

heat-absorbing glass A faintly blue-green plate
or float glass, which absorbs 40% of the sun's
infrared (heat) rays and approximately 25% of the
visible rays that pass through it; must be exposed
uniformly to sunlight (without irregular shadows)
to avoid cracking due to nonuniform heating.

heat- activated adhesive A dry adhesive film
that is rendered tacky or fluid by application of
heat or of heat and pressure.

heat and smoke vent Same as smoke and
fire vent.

heat balance l.A procedure for determining
the efficiency of a combustion process: all heat
losses (expressed as percentages) are added
together; then their total is subtracted from
100%; the remaining figure represents the effi-
ciency. 2. The establishment of a condition of
thermal equilibrium in a space, wherein the heat
gains just equal the heat losses.

heat capacity, thermal capacity The amount
of heat necessary to raise the temperature of a
given mass by 1 degree; numerically equal to the
mass multiplied by the specific heat.

heat conductivity See thermal conductivity.

heat detector An alarm-initiating device in a
fire-detection system that detects abnormally
high temperatures or rates of rise in temperature.

heated space The space within a building with
a positive heat supply.

heat exchanger A device designed to transfer
heat between two physically separated fluids;
generally consists of a cylindrical shell with lon-
gitudinal tubes; one fluid flows on the inside, the
other on the outside.

heat filter An optical filter placed in a light path
to reduce heating effect of a light source; trans-
mits the visible spectrum of the light radiated by
the source, but rejects the near-infrared radiation.

heat flow See heat transfer.

heat-fusion joint A joint in which heat is
used to melt the end of a plastic pipe and the
socket of a plastic fitting into which the pipe is
inserted. When cooled, a solid joint is formed;
can be used only with plain-end plastic pipe and
with fittings manufactured specifically for this
purpose.

heat gain The net increase in heat within a
space.

heating cable See strip heater.

Plastic pipe

Fitting

X^^WWWMSgKS

Fused area

heat-fusion joint

heating capacity, recovery capacity The

capacity of a water heater to raise a given number
of gallons per hour (liters per hour) by a specified
number of degrees, for example, from 40 to 140°F
(4-4 to 60°C); usually expressed in Btu per hour
(kilowatts per hour); does not include the heat
losses in the system which the water heater serves.

heating degree-day Same as degree day.

heating element See electric heating element.

heating load See heat load.

heating medium Any solid or fluid (such as
water, steam, air, or flue gas) which is used to con-
vey heat from a heat source (such as a boiler fur-
nace), either directly or through a suitable heating
device, to a substance or space being heated.

heating plant A system for heating a building
or group of buildings; usually includes a boiler
and a piping system with radiators, or a furnace,
ducts, and air outlets.

heating rate The rate at which temperature is
raised, as for example in an autoclave or kiln;
usually expressed in degrees per hour.

heating system See forced-air heating system,
hot-water heating system, one-pipe system, radi-
ant heating system, sealed hot-water system,
solar heating system, steam heating system,
warm air-heating system.

heating unit See electric heating element.

heating, ventilating, and air-conditioning
system (HVAC system) A mechanical sys-
tem designed to satisfy the environmental condi-
tions within an air-conditioned space, usually
controlling the temperature, relative humidity, dis-
tribution and movement of air, and air cleanliness.

500

heat-transfer fluid

Types of systems differ, but a basic system often
includes an outside-air intake, chiller, preheater,
dehumidifier, heating coil, humidifier, fans, duct-
work, air outlets, and air terminals.

heat-insulating glass See insulating glass.

heat insulation See thermal insulation.

heat load, heating load The total heat per
unit time that must be supplied in order to main-
tain a specified temperature in any space, build-
ing, or group of buildings.

heat loss l.The net decrease in heat within a
space. 2. See building heat-loss factor.

heat of hydration Heat evolved by chemical
reactions with water, as during the setting and
hardening of portland cement.

heat of solution The heat which is liberated
by the solution of a material in a solvent.

heat pump A device that transfers heat from a
cooler reservoir to a hotter reservoir by means of
a heat exchanger, requiring the expenditure of

HtAT
SINK

Tart™

WATER
_0RAIR_

heat pump

mechanical energy in the process; used in an air
conditioner whose cooling cycle can be reversed
so that it can function as a heater.

heat quantity A measured amount of heat,
usually expressed in British thermal units (Btu)
or in kilocalories.

heat recovery The extraction of heat from any
heat source such as lights, engine exhaust, etc.

heat- reflective glass See reflective glass.

heat-release link See fusible link.

heat-resistant concrete Any concrete which
does not disintegrate when exposed to constant
or cyclic heating at any temperature below
which a ceramic bond is formed.

heat-resistant glass Glass able to withstand
higher temperatures than usual because of its
low expansion coefficient.

heat-resistant paint, heat-resistant enamel
A special paint (or enamel) for use in the tem-
perature range between about 250°F and 750°F
(approx. 120°C and 400°C).

heat-sealing A method of joining plastic
sheets or films by the simultaneous application
of heat and pressure to the areas in contact.

heat sink The medium or environment where
heat is discharged after it has been removed from
a heat source; usually the atmosphere or a body
of water.

heat source l.The place or the environment
from which heat is obtained. 2. The place from
which a refrigeration system removes heat.

heat storage The storage of solar energy during
the day, when it is often abundant, for use at a
later time.

heat- strengthened glass Annealed glass: (a)
that has been cut to size, (b) heated to near its
softening point, and (c) then cooled faster than
normal to place the outside surfaces and edges in
compression and the interior in tension; is about
twice as strong as annealed glass.

heat transfer The flow of heat from one body at
higher temperature to another body at a lower
temperature, until the two temperatures are equal.

heat transfer coefficient See thermal con-
ductance.

heat-transfer fluid Liquid which absorbs heat
energy at a heat source (for example, in a solar
collector) and then transports this energy to a
heat exchanger or to its point of use.

501

heat transmission

heat transmission The time rate of heat flow;
usually refers to the combined effects of conduc-
tion, convection, and radiation.

heat transmission coefficient Any one of
several coefficients used in the calculation of
heat transmission by conduction, convection,
and radiation, through various materials and
structures. Also see thermal conductance, ther-
mal conductivity, thermal resistance, thermal
resistivity, thermal transmittance.

heat transmittance Same as thermal transmit-
tance.

heat-treated glass Same as tempered glass.

heat treatment Heating and cooling a solid
metal or alloy in order to produce changes in its
physical and mechanical properties.

heave The upward movement of soil caused by
expansion or displacement resulting from phe-
nomena such as moisture absorption, the
removal of overburden, the driving of piles, and
the action of frost.

heave-off hinge See loose-joint hinge.

heavy-bodied paint A paint having a high
viscosity.

heavy concrete See high-density concrete.

heavy-duty scaffold According to OSHA:
a scaffold designed and constructed to carry
a working load not to exceed 75 lb per sq ft
(367.5 kg per sq m).

heavy grading The moving of large masses of
earth by deep cuts and fills.

heavy joist A timber usually at least 4 in. ( 10 cm)
thick and 8 in. (20 cm) or more in width.

heavy soil A fine-grained soil composed largely
of silt or clay.

heavy-timber construction Construction in
which fire resistance is obtained by using wood
structural members of specified minimum size
and wood floors and roofs of specified minimum
thickness and composition; by using bearing
walls and nonbearing exterior walls of noncom-
bustible construction; by avoiding concealed
spaces under floors and roofs; and by using
approved fastenings, construction details, and
adhesives for structural members.

heavyweight aggregate Aggregate of high
specific gravity such as barite, magnetite, limo-
nite, ilmenite, iron, or steel; used to produce
high-density concrete.

heavyweight concrete See high-density con-
crete.

hecatompedon A building 100 ft (30.5 m) in
length or width; esp. the cella of the great tem-
ple of Athena, the Parthenon, at Athens.

hecatonstylon A building having a hundred
columns.

heck l.A door having its upper part hinged
independently of its lower part, or one with an
open or latticework panel. 2. A latticed gate.

hectare A metric unit of area equal to 10,000
square meters; approximately VA acres.

hectastyle Same as hexastyle.

hedge l.A barrier or fence formed by bushes or
small trees growing close together; 2. A closely
grown row of any kind of shrubbery.

hedgerow Trees and shrubs in a row forming a
fence which encloses or separates fields.

heel 1. The lower end of an upright timber, esp.
one resting on a support. 2. The lower end of the
hanging stile of a door. 3. The floor brace for
timbers that brace a wall. 4. The trailing edge of
the blade of a bulldozer, or the like.

heel cut Same as seat cut.

heelpost l.A post or stanchion at the free end
of the partition of a stall. 2. A post to receive the
hinges of a gate (either part of the gate or the
stationary support).

heel stone A stone at the bottom of a gate pier;
used to mount the bottom hinge pin for the gate.

heel strap A steel fastener used to join a rafter
to its tie beam.

height l.The distance between two points
aligned vertically. 2. In buildings, the distance
vertically from the average grade at front sides
and/or rear of a building (or the average eleva-
tion of the curb or curbs of the streets faced by
the building) to the average level of the roof.

height board A gauge used in the construc-
tion of stairs for setting the heights of the risers.

height zoning See zoning.

held water Same as capillary water.

helical hinge A special type hinge for a double-
acting door.

helical reinforcement A steel reinforcing rod
in the form of a helix.

helical stair A spiral stair.

helicline A spiral ramp.

502

herbaceous border

heliodon A device used to orient a light source
(representing the sun) with respect to an archi-
tectural model; calibrated in terms of latitude,
time of day, and season of the year; used to study
daylighting techniques and to illustrate the
shadows cast by direct sunlight.

helioscene Same as shade screen.

heliport A facility where helicopters land, take

off, and are maintained or repaired.
helix 1 . Any spiral, particularly a small volute or

twist under the abacus of the Corinthian capital.

2. The volute of an Ionic capital.

helix, 1: H

helix stair Same as spiral stair.

Hellenic Pertaining to the classical Greek
period, roughly from 480 B.C. to the death of
Alexander in 323 B.C.

Hellenistic Characteristic of the style of Greek
art after the death of Alexander in 323 B.C.

helm roof A roof having four faces, each of
which is steeply pitched so that they form a
spire; the four ridges rise to the point of the spire
from a base of four gables.

helve The handle of an ax, adz, hatchet, etc.
hem The projecting spiral of a volute of an
Ionic capital.

hemicycle 1. A semicircular arena. 2. A room
or division of a room in the form of a semicircle.
3. A semicircular recess.

hemicyclium A semicircular alcove, sufficiently
large to provide seating for a group of people.

hemiglyph The half channel on each of the
two sides of a triglyph.

hemihydrate A hydrate which contains one-
half molecule of water to one molecule of the
compound; the most common such material is
partially dehydrated gypsum (plaster of paris).

hemihydrate plaster Same as plaster of paris.

hemitriglyph The portion of a triglyph which
sometimes occurs in an internal angle of a
returned frieze which has triglyphs in it.

hemlock Wood of a coniferous tree of the US.
Also see eastern hemlock, western hemlock.

hemlock spruce See eastern hemlock.

hench 1 . The narrow side of a chimney stack.
2. Same as haunch.

henhouse See poultry house.

henostyle in antis Having a single column in
the front of a building, set between antae.

Henri II (Deux) style The second phase of the
early French Renaissance, named after Henri II
(1547-1559) who succeeded Francis I. Italian clas-
sic motifs began to supplant the Gothic elements,
both in architecture and in decoration. The west
side of the Court of the Louvre (1547-1559) is an
outstanding example. (See illustration p. 504-)

Henri IV (Quatre) style The early phase of
the Classical period of French architecture,
named after Henry IV (1589-1610), preceding
the architecture of Louis XIII and Louis XIV. It
is particularly strong in domestic architecture
and town-planning arrangements. The Place des
Vosges in Paris (1605-12) is the outstanding
example. (See illustration p. 504.)

HEPA filter A high efficiency particulate
absolute filter capable of trapping and retaining
at least 99.9% of asbestos fibers greater than
0.3 microns in length.

heptastyle A portico having seven columns, at
one or at each end. (See illustration p. 504-)

Heraeum A temple or sacred enclosure dedi-
cated to the goddess Hera.

herbaceous border A permanent border of
nonwoody perennials, often against an ever-
green background or a stone wall.

503

herm

Henri II style: west side of the Court of the Louvre

■ "IS" iYi ' :■■ t!^ 3 v -f«Hy. .:■ jYli

!_ m&Lj '■+ -'■ ■ — iPX-tn — ( — I _febs_J ■ /->
_~Tp ",--i Jr- - - t A y^JH — iZT- -:■-'■ -> .-i

heptastyle

herm A rectangular post, usually of stone and
tapering downward, surmounted by a bust of Her-
mes or other divinity, or by a human head.

Henri IV style: Place des Vosges, Paris (1605-12)

herm

504

hex barn

hermitage l.A private retreat. 2. A secluded
hideaway. 3. A house of certain monastic orders.

heroum A building or sacred enclosure ded-
icated to a hero, usually erected over a grave.

herringbone bond In masonry, a type of rak-
ing bond in which the rows of headers are laid at
right angles to each other so as to form, in plan,
a series of zigzags.

herringbone bracing Same as herringbone
bridging.

herringbone bridging A system of braces
between joists to stiffen the joists, to hold them in
place, and to distribute their load; these braces
alternate in direction along the joists, giving rise
to a herringbone-like pattern. Also called herring-
bone strutting, cross bridging, diagonal bridging.

herringbone bridging

herringbone matching See book matching.

herringbone pattern A way of assembling, in
diagonal zigzag fashion, brick or similar rectangular
blocks for paving and for masonry walls; also strips
of wood or other finishing materials having rect-
angular shapes for facing walls or ceilings.

herringbone pattern in brickwork

herringbone strutting Same as cross bridging.

herringbone work In masonry, a pattern in
which the masonry units are laid at an angle of
45° to the general direction of the row; reversing

the inclination in alternate rows forms a zigzag
effect.

herse Same as hearse.

Hertfordshire spike Same as needle spire.

hertz A unit of frequency, abbr. Hz; one cycle
per second.

hesitation set See false set.

hessian Same as burlap.

hew stone A stone that has been hewn, 1 .

hewn 1. Roughly dressed, as stone shaped with
mallet and chisel. 2. Roughly shaped with an ax,
as hewn logs.

hewn-and-pegged joint A mortise-and-tenon
joint formed by cutting a tenon to fit a corre-
sponding mortise, joining these two members, and
then securing them with a wood pin. Such joints
are used, for example, in post-and-girt framing.

hewn overhang In an early timber-framed
house, the modest projection of an upper story
beyond the story immediately below it, usually
no more than a few inches. A heavy timber post
extended from the foundation of the house to
the upper story; this post was hewn away from
just below the upper story down to the ground-
sill, thereby creating the appearance of an upper
story slightly overhanging the lower one. Com-
pare with framed overhang.

HEX On drawings, abbr. for "hexagon" or
"hexagonal."

hexagonal method of application See
French method of application.

hexapartite vault Same as sexpartite vault.

hexastyle, exastyle Having six columns, as at
one end or at each end of a portico.

hexastyle

hex barn A barn decorated with painted hex
symbols called hexenfoos, i.e., colorful geometric

505

hexenfoos (

i hex barn

patterns set within circles, particularly found on
barns in Pennsylvania Dutch regions. The sym-
bols probably were originally intended to protect
the animals from harm cast by the "evil eye."

HF On drawings, abbr. for "hot finished."

HGT On drawings, abbr. for height.

H-hinge, parliament hinge, shutter hinge
A type of strap hinge with leaves enlarged so that
when the hinge is open, it forms the letter H.

hickey, hicky l.A threaded fitting for
mounting a lighting fixture in an outlet box, or
on a stud or pipe. 2. A tool for bending conduit
or pipe.

hickey, 2

hick joint See rough-cut joint.

hickory A tough, hard, strong wood of North

America; has high shock resistance and high

bending strength.
HID Abbr. for "high-intensity discharge."
hidden joint A joint between slabs of stone

which is made invisible by caulking.
hidden line On an architectural drawing, a

dashed line that represents a line which exists

but is concealed from view.
hidden nailing Same as blind nailing.
hide glue See animal glue.
hiding power, covering power The ability

of a paint film to obscure completely any pattern,

marks, or color on the surface to which it is
applied.

hieroglyph A figure representing (a) an idea, and
intended to convey a meaning, (b) a word or root
of a word, or (c) a sound which is part of a word;
esp. applied to the engraved marks and symbols
found on the monuments of ancient Egypt.

hieron The sacred enclosure of a temple or
shrine.

high altar The primary altar in a church.

high-alumina cement See calcium alumi-
nate cement.

high-bay lighting A lighting system with
luminaires of the direct or semidirect type,
mounted high above the floor; used principally
in industrial installations.

high-bond bar A deformed bar.

high-bond mortar Any mortar for masonry
construction that provides higher bond strength
than can be obtained with the usual mortar.

high brass See common brass.

high-build coating A coating composed of a
series of uniform tile-like films which are applied in
thicknesses (minimum 5 mils) greater than those
normally associated with paint films and thinner
than those normally applied with a trowel.

high-calcium lime A lime which contains
mostly calcium oxide or calcium hydroxide and
not over 5% magnesium oxide or hydroxide.

high-carbon steel A steel having a carbon
content between 0.6% and 1.5%.

high chair Same as bar support.

high-challenge fire hazard A fire hazard
typically produced by a fire in combustible piled-
high storage.

high-density concrete, heavy concrete,
heavyweight concrete Concrete of ex-
ceptionally high unit weight, usually consisting
of heavyweight aggregates; used esp. for radia-
tion shielding.

high-density overlay An overlay consisting
of paper that is impregnated with a thermo-
setting resin and then applied to plywood;
provides a smooth, hard, wear-resistant surface
for high-quality concrete formwork and decking.

high-density plywood Plywood made from
resin-impregnated veneer and formed with heat
at pressures of 500 lb per sq in. (35 kg per sq m)

506

high-pressure steam heating system

or more; usually density is at least twice that of
normal plywood; is difficult to work with ordi-
nary hand tools because of its extreme hardness.

high-discharge mixer See inclined-axis mixer.

high-early-strength cement, extra-rapid-
hardening cement, type III cement
Cement producing earlier strength in mortar or
concrete than regular cement.

high-early-strength concrete Concrete
which, through the use of high-early-strength
cement or admixtures, is capable of attaining
specified strength at an earlier age than normal
concrete.

high explosive A material that detonates
almost instantaneously.

high gloss See gloss.

High Gothic Same as the Decorated style, the
second of the three phases of English Gothic
architecture.

high hat l.A recessed downlight. 2. A black
circular tube which is mounted on the front of a
spotlight to reduce the stray light on the sides of
the main beam.

high-hazard contents Building contents that
are liable to burn with extreme rapidity and/or
from which poisonous fumes or explosions are to
be feared in the event of fire.

high-hazard industrial occupancy Use of

a building having high-hazard contents.
high-intensity discharge lamp One of a

group of mercury, metal halide, or high-pressure
sodium lamps.

high-joint pointing Pointing done during the
progress of the work, while the mortar is still
soft, first by trimming the joints flush with the
face of the wall, and then scraping grooves along
the edges of the brick at both sides of the joint.

high-lift grouting The technique of grouting
masonry in which each lift, 7 is raised 12 ft (3.7 m)
or more in height.

highlight 1 . In a field of view, a local region that
is emphasized, usually by increased local illumi-
nation. 2. An area on a metal surface which has
been most exposed to a buffing or polishing oper-
ation, and hence has the highest luster.

high-light window Same as clerestory, 2.

high-magnesium lime A lime produced by
calcining dolomitic limestone or dolomite;

contains more magnesium oxide than limes
made from calcite or high-calcium limestones
and marbles; ranges from 37 to 41% magnesium
oxide content. Incorrectly called "dolomitic
lime."

high-melting-point asphalt Roofing asphalt
which melts at a higher temperature than is
usual; used on steep slopes and to attach insula-
tion and/or vapor barriers to the structural deck.

high-output fluorescent lamp A rapid-start
fluorescent lamp designed to operate on higher
current than usual, resulting in a corresponding
increase in flux (lumens) per unit length of the
lamp.

high polymer A substance composed of a
large molecule which usually but not always
consists of repeat units of the low molecular
weight; one having a molecular weight greater
than 10,000.

high-pressure boiler A boiler that provides
steam at pressures above 15 lb per sq in. (103.4
kPa) or hot water at temperatures exceeding
250°F(121°C).

high-pressure laminates Laminates molded
and cured at pressures not lower than 1,000 lb
per sq in. (70 kg per sq cm) and more commonly
in the range of 1,200 to 2,000 lb per sq in. (84 to
140 kg per sq cm).

high-pressure mercury lamp A mercury-
vapor lamp that operates at a partial pressure of
mercury of about 1 atmosphere or more.

high-pressure overlay Any plastic laminate
composed of phenolic or melamine-impregnated
papers (often printed or patterned for decorative
effects) which are pressed into hard sheets at
high pressures. Such sheets have excellent wear
resistance; often glued to wood substrates for
tabletops and doors.

high-pressure sodium lamp A sodium-
vapor lamp in which the partial pressure of the
vapor during operation is about 0.1 atmosphere;
produces a yellowish light having a wide spec-
trum, in contrast to the light produced at low
pressures, which is characterized by sodium emis-
sion lines.

high-pressure steam heating system A
steam heating system employing steam at pres-
sures usually above 100 lb per sq in. (7 kg per
sq cm).

507

high relief

high relief, alto-relievo, alto-rilievo Sculp-
ture relief work in which the figures project more
than half their thickness.

high relief

High Renaissance A term referring primar-
ily to the culmination of the Italian Renais-
sance style in the 16th century (cinquecento) .
Saint Peter's in Rome is the most famous
example.

high-rise A building having a large number of
floors, usually constructed where land costs are
high.

high-rise building Said of a building that is
many stories in height, usually higher than ten
to twelve stories.

high school, secondary school In the US,
a school which provides education beyond ele-
mentary school, usually from grade 9 to grade
12 but occasionally including grades 7 and 8.

high-silicon bronze See silicon bronze.

high-silicon iron pipe Same as acid-resistant
cast-iron pipe.

high steel Steel containing a comparatively
large amount of carbon (0.5 to 1%).

high-strength bolt A bolt made of either high-
strength carbon steel or quenched and tempered
alloy steel.

high-strength concrete In concrete, the use
of a high cement-to-water ratio and a special

High Renaissance: interior of St. Peter's, Rome

508

hinge jamb

admixture, such as a combination of a superplas-
ticizer and silicate dust, intended to achieve a
higher-than-standard strength.

high-strength low-alloy steel Steel having
a chemical composition specifically developed
to impart higher mechanical property values
and, in some cases, greater resistance to atmo-
spheric corrosion than is obtainable from con-
ventional carbon steels.

high-strength steel Steel which has a high yield
point, e.g., 6000 pounds per square inch (4-4 MPa) .

high-style architecture A term occasionally
applied to the latest au courant architecture style,
although it not actually a style of architecture;
sharply contrasts with established architectural
styles such as folk architecture or vernacular
architecture.

High-Tech architecture A mode of architec-
ture in which the building services are not only
revealed, but are emphasized. For example, ducts
and pipes may be painted in bright colors to indi-
cate their respective functions. An outstanding
example is the Pompidou Centre in Paris.

high-temperature brazed joint A gastight
joint which is brazed at temperatures higher
than 1500°F (816°C) but less than the melting
temperatures of the joined parts.

high-temperature-water heating system

A heating system in which water having supply
temperatures above 350°F (177°C) is used as a
medium to convey heat from a central boiler,
through a piping system, to suitable heat-distrib-
uting means.

high-tensile bolt See high-tension bolt.

high-tensile reinforcement Steel reinforc-
ing bars for concrete having a minimum yield
strength above a specified value.

high-tensile steel A low-alloy steel having an
yield strength of 50,000 to 100,000 pounds per
square inch (3.4 X 10 8 to 6.9 X 10 8 newtons per
square meter). Also called high-strength steel.

high-tension bolt A high-strength bolt which
is tightened with a calibrated torsion wrench;
used in place of a rivet.

high tomb Same as altar tomb.

high-transmission glass A glass that trans-
mits a very high percentage of light which is
incident on its surface.

high-velocity duct system A duct system

in which the air velocities are 2,400 ft (approx.
730 m) per minute or higher.

High Victorian architecture See Victorian
architecture.

High Victorian Gothic A very elaborate,
highly detailed interpretation of the Gothic
Revival in its last phase, from about 1860 to
1890; may have bands of polychromed masonry
and multicolored brickwork or roofing tiles; is
heavy in appearance, as exemplified by its mas-
sive gables and porches; sometimes called Late
Gothic Revival or Ruskinian Gothic. Some
architectural historians avoid this designation,
regarding the adjective "Victorian" merely as
descriptive of an age that encompassed a number
of specific exuberant, ornate, and highly decora-
tive architectural styles.

High Victorian Italianate A term some-
times applied to the latter phase of Italianate
style, from the 1860s to 1880; often more elabo-
rate than the earlier Italianate style.

hiling The covering or roof of a building.

hinge A movable joint used to attach, support,
and turn a door (or cover) about a pivot; consists
of two plates joined together by a pin which sup-
port the door and connect it to its frame,
enabling it to swing open or closed. Also see
action hinge, butterfly hinge, butt hinge, dove-
tail hinge, gravity hinge, H-hinge, HL-hinge,
pintle hinge, side hinge, strap hinge.

hinge backset The horizontal distance from the
edge of a door hinge to the stop side of the door.

hinged latch bolt Same as swinging latch bolt.

hinge jamb The door jamb to which hinges are
attached.

BUTT

HINGE WALL
3^ /"FINISH

DOOR

hinge jamb

509

hinge joint

hinge joint Any joint which permits action
similar to a hinge and in which there is no
appreciable separation of adjacent members.

hingeless frame See rigid frame.

hinge post See hanging post.

hinge reinforcement A metal plate attached
to a door or doorframe to receive a hinge.

hinge stile The vertical structural member of a
doorframe on which the hinges are fixed, and
about which the door pivots; also called a hang-
ing stile.

hinge strap A metal strap, often ornamental,
which is fixed to the surface of a door to give the
appearance of a strap hinge.

hinging jamb Same as hinge jamb or hanging
jamb.

hip 1. The external angle at the junction of two
sloping roofs or sides of a roof. 2. The rafter at
the angle where two sloping roofs or sides of
roofs meet. 3. The joint of a bridge truss where
the top chord meets the inclined end post.

hip capping The top strip of roofing felt or
other protective covering over a hip.

hips, 1 (flush panel type)

hip-and-valley roof A roof constructed so
that it has both hips and valleys.

hip-and-valley roof

hip bevel 1. The angle between two slopes of a
roof which are separated one from the other by a
hip. 2. The bevel that must be given to the end
of a rafter so that it will conform to the oblique
construction at a hip.

HIP CAPPING

FLASHING

hip capping

hip-gambrel roof In the US, a combination of
a hip roof and a gambrel roof.

hip-gambrel roof

hip hook, hip iron A metal strip, usually of
wrought iron, installed at the foot of a hip rafter;
used to fix the hip tiles in place.

hip iron A hip hook.

hip jack A jack rafter, one end of which termi-
nates at the hip of a roof.

hip joint Same as hip, 3.

hip knob A finial or other similar ornament
placed on the top of the hip of a roof or at the
apex of a gable.

hip molding A molding on the rafter that
forms the hip of a roof.

hip-on-gable roof Same as jerkinhead roof.

hipped dormer A dormer whose roof has flat
surfaces that slope upward at the front of the
dormer, as well as on both sides, in a manner
similar to that of a hipped roof.

hipped end The sloping triangularly shaped
end of a hipped roof.

hipped gable See jerkinhead.

hipped-gable roof A seldom-used term for
jerkinhead roof.

510

HL-hinge

hipped-plate construction See folded-plate

construction.
hipped roof, hip roof A roof comprising

adjacent flat surfaces that slope upward from all

sides of the perimeter of the building, requiring a

hip rafter along each intersection of the inclined

surfaces; also see pyramidal roof.
hippodrome l.A circus. 2. A modern sports

arena of any shape.
hip rafter, angle rafter, angle ridge A

rafter placed at the junction of the inclined

planes forming a hipped roof.

CEILING

JOIST

■*- HIP RAFTER

hip rafter

hip rib On domed roofs, a curved hip rafter.
hip roll, ridge roll A rounded strip of wood,

tile, metal, or composition material which is

used to cover and finish the hip of a roof.
hip roof, hipped roof A roof which slopes

upward from all four sides of a building, requiring

a hip rafter at each corner.

hip roof

hip skylight A skylight having sloping sides

that meet to form hips, 1 .
hip tile A saddle-shaped tile used to cover the

hips of a roof.

hip vertical The upright tension member
which is attached to the hip, 3 of a truss, carries
a floor beam at its lower end.

Hispanic Colonial architecture See Spanish
Colonial architecture.

historiated capital A capital having carvings
that depict an event or story.

Historic American Buildings Survey
(HABS) A collection of measured drawings,
photographs, and records of American buildings,
constructions, and sites that (a) are of particular
historic interest, significance, or are representa-
tive of a particular architectural style; (b) repre-
sent important methods of construction; (c)
were designed by a major architect; and/or (d)
are typical of work by an ethnic group within the
United States. Housed in the Library of Con-
gress, HABS represents an important, useful,
and significant resource. Address: National Park
Service, Department of the Interior, P.O. Box
37127, Washington, DC 20013-7127.

historic building A building that is listed or is
eligible for listing in the US National Register of
Historic Places, or in equivalent registers of any
country, state, shire, county, or locality.

historic fabric Those portions of a building
fabric that are of historic significance.

historic marker See marker.

historic preservation See building preser-
vation.

historic structure report A document pre-
pared for a historic building or structure, land-
scape, or group of properties; records and analyzes
the building or property's initial construction and
subsequent alterations by making use of docu-
mentary physical and pictorial evidence.

hit-and-miss window A window, the upper
sash of which is glazed, the lower sash containing
two movable panels that are slotted; one panel
slides completely across the other, providing an
opening for air which may be adjusted as required.

Hittite architecture The distinctive rugged
architecture created in central Anatolia at the
time of the Hittite Empire (14th to 13th cent.
B.C.), preeminent for its fortifications, citadels,
and temples.

HL-hinge A type of H-hinge that has a hori-
zontal extension added to a foot of the hinge.
(See illustration p . 512.)

511

HMD

HMD Abbr. for hollow-metal door.

hoarding, hoard l.A rough and temporary
wall or fence, usually at a construction site. 2. A
covered wooden gallery projecting from the top
of the wall of a medieval fortress to shelter the
defenders and to increase facilities for defense.

hob A flat projecting shelf at the side of a fireplace
where pots or pans may be placed to keep warm.

hod A wood or metal container, usually V-
shaped with a long handle and having one end
open; used in masonry work to carry plaster or
lime putty to the mortarboard.

hoe See backhoe.

hogan The traditional single-family dwelling of
the Navajo Indians of the American Southwest;
typically has a framework constructed of logs,
poles, branches, and sticks that is covered with a
layer of bark and then a thick layer of mud or
sod. A smoke hole, centered at the top of the
structure, provides light and carries off fumes
and smoke from an open firepit located directly
below; there are no windows.

hog-backed Cambered; applied esp. to the
ridge of a roof which appears to sag in the middle.

hoggin l.A graded gravel (or the like) used as a
base for paths, sidewalks, roads, etc. 2. A mix-
ture of gravel and sand with clay.

hogging The drooping of the extremities and
consequent convex appearance of any timber
supported in the middle.

hog's-back tile A ridge tile whose section is
not quite half round.

hoist 1. In building, a machine for lifting workers
and materials to upper stories during erection of
the structure. 2. A machine that provides power
drive to a cable drum used to pull or lift a load.

hoisting machine A power-operated machine,
used for lifting or lowering a load, that utilizes a
drum and wire rope (excluding elevators);
includes but is not limited to a cableway, crane,
or derrick.

hoist tower In building erection, a temporary
(sometimes portable) structure that provides
guideways for a platform that lifts materials to
upper stories.

hoist tower

hoistway A passage through which an object
may be raised; for example, an elevator shaft.

hoistway door A door between an elevator
shaft or hoistway and the floor landing, normally
closed except when the elevator is stopped at
the floor for passengers or freight.

hoistway door interlock A device used to
prevent the operation of a hoisting machine
unless the hoistway door is locked in the closed
position; used to prevent the opening of this
door from the landing side unless the car is
within the landing zone and is either stopped or
being stopped.

hold-down bolt See anchor bolt.

hold-down clip l.In a suspended acoustical
ceiling, a flexible metal clip used to hold an
acoustical ceiling board or lay-in panel in firm
contact with the supporting members of an
exposed suspension system. 2. In roofing, a flex-
ible metal clip used to hold adjacent lengths of
capping in place.

holder bat An escutcheon, 2 having a pro-
jecting lug on one side for attaching it to a
wall.

512

hollow plane

holdfast A device for securing anything in its
place, as a hook, bolt, spike, etc.

hold harmless l.See contractual liability.
2. See indemnification.

holding-down bolt Same as anchor bolt.

holding period Same as presteaming period.

hole saw See crown saw.

holiday, skip 1 . A small area on a painted sur-
face which the brush skipped over, leaving it
bare. 2. An area on a built-up roof surface which
the mop (used to coat the surface) skipped over,
leaving it uncovered by bitumen.

holing The punching of holes in slates before
fixing on a roof.

hollow-backed Said of a piece of wood, stone,
etc., whose unexposed face has been hollowed
out so that it fits against an irregular surface
more tightly.

hollow bed In masonry a bed joint in which
there is no mortar at the center of a stone (or in
which the stone is not flat but hollowed) so that
contact is made only along the edges.

hollow block A hollow masonry unit.

hollow brick 1. (US) A hollow clay masonry
unit whose net cross-sectional area in every
plane parallel to the bearing surface is not less
than 60% of its gross cross-sectional area mea-
sured in the same plane. 2. (Brit.) A brick hav-
ing holes through it which total at least 25% of
its volume, the holes being not less than 3 A in.
(1.91 cm) wide or 3 Asq in. (4-84 sq cm) in area.

hollow chamfer A chamfer which is concave.

hollow clay tile Same as structural clay tile.

hollow concrete block A concrete hollow
masonry unit.

hollow-core construction A construction
having a lightweight inner core which is faced
on both sides by a material such as plywood or
hardboard.

hollow-core door A flush door of hollow-core
construction.

hollow glass block See glass block.

hollow gorge Same as Egyptian gorge.

hollow masonry unit A masonry unit
whose net cross-sectional area in any plane
parallel to the bearing surface is less than 75%
of its gross cross-sectional area measured in the
same plane.

hollow masonry units

hollow- metal Said of an assembly that is fabri-
cated of formed light-gauge metal.

hollow-metal door A metal door (commonly
of the flush type), fabricated of sheet steel and
reinforced by light metal channels; has a hollow
core, sometimes filled with a light filler material.

CENTER PANEL

HINGE
REINFORCEMENT

^5.

END CHANNEL

LOCK STILE

LOCK
REINFORCEMENT

hollow-metal door

hollow-metal fire door A hollow-metal door
fabricated of sheet steel, No. 20 gauge or heavier,
and filled with an approved fire-proof insulating
material.

hollow molding, gorge, trochilus A con-
cave, often circular molding; a cavetto or scotia.

hollow newel, hollow newel stair 1 . The
newel or central shaft of a winding stair built as
a hollow cylinder. 2. The open well in such a
stair when built without the hollow enclosure.

hollow newel stair See open-newel stair.

hollow partition See cavity wall.

hollow plane A carpenter's molding plane
with a convex blade for forming concave or hol-
low moldings.

513

hollow relief

hollow relief Same as sunk relief.

hollow roll A type of joint (between two sheets
of metal roofing) in the direction of maximum
slope of the roof; the two pieces are turned up at
the joint and then bent to form a hollow cylin-
drical roll.

hollow square molding A common Norman
molding consisting of a series of indented pyra-
midal shapes having a square base.

RKKJHE.

hollow square molding

hollow tile Same as structural clay tile.
hollow-tile floor slab A reinforced concrete

floor slab, cast over rows of structural clay tile.
hollow-unit masonry Masonry constructed

of hollow masonry units laid in mortar.
hollow wall, hollow masonry wall See

cavity wall,
hollow-web girder Same as box beam.
Holy door In a Greek Orthodox church, the

door to the iconostasis.
holy-water stone A stone basin for holding

holy water, placed near the entrance of a church.

holy-water stone

home for the aged An institution which pro-
vides primarily domiciliary or custodial services
and minimal nursing and medical care to aged
persons.

homestall See homestead, 2.

homestead 1. In the United States, under the
Homestead Act of 1862, a tract of unoccupied
public land, 160 acres in area, that could be
permanently acquired after five years of contin-
uous occupancy and the payment of a fee. The
Act was passed by the Congress to promote
westward expansion and for the purposes of
revenue; this quantity of acreage was deemed
adequate for the support of one family. Any cit-
izen who settled on such survey public land
could purchase it from the government if he
was the head of a family and over 2 1 years of
age. 2. The house built on such a tract. 3.
(Brit.) A group of buildings and the land form-
ing the home of a family.

homogeneous material A material whose
characteristics or properties are not a function of
the position within the material.

hone Same as oilstone.

honed finish A very smooth stone surface, just
short of polished; imparted by a rubbing process,
either hand or mechanical.

honeycomb 1 . Any hexagonal structure or
pattern, or one resembling such a structure or
pattern. 2. Voids left in concrete owing to failure
of the mortar to fill effectively the spaces among
coarse aggregate particles. 3. A type of flaw in
metal caused by corrosion or imperfect casting.

honeycomb, 1

honeycomb brickwork In a brick wall, the
omission of some headers or stretchers either to

provide ventilation or to serve as a decorative
element.
honeycomb core A material of sandwich con-
struction having a strong, thin-walled hexagonal
structure resembling a honeycomb.

514

hoop reinforcement

honeycombing Checks or splits that develop
inside a piece of wood during drying; usually not
visible on the surface.

honeycomb slating Similar to diagonal slat-
ing except that the bottom corners are removed
from the slates.

honeycomb structure An arrangement of
soil particles having a comparatively loose, sta-
ble structure resembling a honeycomb.

honeycomb vault, honeycomb work See
muqarnas.

honeycomb wall A brick wall having a pat-
tern of openings; equal in thickness to the width
of one brick; either gaps are left between stretch-
ers or bricks are omitted to provide openings;
used to support floor joists and provide ventila-
tion under floors.

honeysuckle ornament A common name
for the anthemion, common in Greek decorative
sculpture.

honeysuckle ornament

honing gauge A device for holding a chisel at
the same angle while it is sharpened on a flat
stone.

hood 1. A cover placed above an opening or an
object to shelter it. 2. A cover placed over a fire
or chimney to create a draft and to direct the
smoke, odors, or noxious vapors into a flue; may
be supported or hung in space, or attached to a
wall; sometimes furnished with a grease filter or
extractor, a light fixture, and fire-extinguishing
system.

hooded crown The upper termination of a
window that is covered by a hood, 1 .

hoodmold, hood molding The projecting
molding of the arch over a door or window,
whether inside or outside; also called a dripstone.

hook 1. A curved or bent metal device used for
attachment. 2. A bend in the end of a reinforc-
ing bar; also see hooked bar.

hood, 1

hook-and-butt joint, hook butt scarf, hook
scarf A type of scarf joint for joining timbers
endwise so that they lock into each other.

hook-and-eye fastener A two-piece metal
fastener consisting of a hook, bent to the
required shape, and an eye through which the
hook fits.

hook bolt A bolt having one end in the form of
a hook.

hook bolt

hooked bar A steel reinforcing bar, for use in

reinforced concrete, with the end bent into a
hook to provide anchorage.

Hooke's law A law stating that the deforma-
tion of an elastic body is proportional to the
force applied, provided the stress does not
exceed the elastic limit of the material.

hook strip A wood board, attached to a wall of
a closet, to which clothes hooks are fastened.

hoop iron Thin strips of iron used to bond
masonry.

hoop-iron bond In masonry, a chain bond
formed by metal straps or hoop iron.

hoop reinforcement In concrete columns
and piles, steel rings (other than helical) which
are placed around the reinforcing bars or rods
of the main reinforcement to tie them together.

515

hoop tension

hoop tension The horizontal tension around
the lower part of a dome.

hopper l.A funnel-shaped bin or chute; used
to store loose construction materials, such as
crushed stone or sand. 2. One of two barriers on
both sides of a hopper light to prevent airflow
through the side openings at the ends of the
inward-sloping pivoted sash (ventilator, 2). 3. A
water tank which releases its contents through
a pipe at the bottom; esp. used with a water
closet. 4. A water-closet bowl, esp. one that is
funnel-shaped. 5. See collection hopper.

hopper frame A type of window frame having
an upper sash (ventilator, 2) which is hinged
along the bottom and opens inward; some
frames of this type contain several such sashes.

hopper head A funnel-shaped leader head.

hopper light l.A window sash which opens
inward and is hinged at the bottom; when open,
air passes over the top of the sash; also called
hopper vent or hopper ventilator. 2. A window
sash which opens inward and is hinged at each
side; when open, most of the air passes over the
top of the sash but there is some flow through a
narrower opening along the bottom.

hopper light

hopper vent, hopper ventilator See hop-
per light, 1 .
hopper window A hospital window.

HOR On drawings, abbr. for horizontal.
horizon The apparent or visible junction of the
earth and sky, as seen from any specific position.

horizon cloth A cyclorama fabricated of canvas.

horizon light A lighting unit used to illumi-
nate a cyclorama from below, e.g., from a light
trough.

horizontal At right angles to the direction of
gravity; on the level; parallel to the horizon; nei-
ther vertical nor inclined.

horizontal angle An angle in a horizontal
plane.

horizontal-axis mixer A concrete mixer
having a revolving drum which rotates about a
horizontal axis.

horizontal bracing Any bracing which lies in
a horizontal plane.

horizontal branch A branch drain with a
horizontal extension from a waste, soil, or vent
stack, or from a building drain, which receives
the discharge from a single fixture or a group of
fixtures and conducts it to the soil or waste stack
or to the building drain.

(V SOIL STACK

HORIZONTAL BRANCH

horizontal branch

horizontal bridging 1 . Any bridging in a hor-
izontal plane. 2. Bridging which is perpendicular
to, and lying in the planes of, the flanges of joists
or beams.

horizontal cell tile A structural masonry
ceramic tile having cells whose axes are horizon-
tal when the tile is placed in the wall.

horizontal circle A graduated circle fixed to
the lower plate of a transit, by means of which
horizontal angles can be measured.

horizontal control In surveying, a basic
framework of points whose horizontal position
and interrelationship have been determined
accurately.

516

horn

horizontal bridging, 1

horizontal cornice The level cornice of the
pediment under the two inclined cornices.

horizontal diaphragm A floor deck or roof
used as part of a lateral bracing system.

horizontal exit A means of passage from one
building into another building occupied by the
same tenant, or from one section of a building
into another section of the same building occu-
pied by the same tenant, through a separation
wall having a specified fire-resistance rating.

horizontal line A line perpendicular to the
vertical.

horizontal panel On a wall, a panel whose
longest dimension is horizontal.

horizontal passage A passageway between
rooms or between areas on the same floor level
of a building.

horizontal pipe Any pipe which is horizontal
or makes an angle of less than 45° with the
horizontal.

horizontal plane A plane perpendicular to
the direction of a plumb line.

horizontal shear A measure of the resistance
to shear stress along the longitudinal axis of a
piece of wood.

horizontal sheeting In excavation work,
timber planks, sheets of steel, panels of con-
crete, or the like, which are placed between sol-
dier piles to provide a restraint to retain the soil.

horizontal shore Same as flying shore.

horizontal shoring 1. Adjustable span mem-
bers, of either the beam or truss type; used to
support concrete forms over relatively long
spans, thereby reducing the number of vertical

<y/A\v/Av/A\y

horizontal sheeting

supports. 2. A number of horizontal shores act-
ing collectively.

horizontal sliding door A door and frame
with a track arrangement permitting the door to
slide horizontally.

horizontal sliding window, horizontal
slider A window having sashes (in a vertical
plane) which slide in horizontal grooves or
tracks; when closed, the stiles of the sashes meet
and may interlock.

horizontal spring hinge A spring hinge that
is mortised horizontally into the bottom rail of a
door and fastened to the floor and head frame
with pivots.

H or M In the lumber industry, abbr. for "hit or
miss."

horn 1. Any projecting end of one of the mem-
bers of a right-angle wood framing joint. 2. The
extension of a sash stile below the bottom rail of
an upper-hung sash, either for styling or to serve as
a stop. 3. A horizontal extension of a windowsill
beyond the jamb. 4. Same as spur, 1. 5. A volute,
1. 6. An acroterion, 2.

horn, 1

517

hornwork

hornwork Fortress outwork with two half bas-
tions.

hors concours Describing an invited exhibit
or exhibitor, ineligible for an award in a compe-
tition owing to acknowledged superiority.

horse 1. See sawhorse. 2. See carriage. 3. Fram-
ing used as a temporary support.

horse block A block or platform, often set
near a door, on which one steps when mounting
or dismounting from a horse.

horsed joint Same as saddle joint, 1 .

horse mold A running mold.

horsepower A unit of power equal to 746 watts.

horsepower-hour A unit of work or energy
equal to the work done by a machine having a
power output of 1 horsepower over a period of
1 hour.

horse scaffold A scaffold for light or medium
duty, composed of horses supporting a work
platform.

horse shed A rough structure having one or
more open sides, once used to provide temporary
shelter for horses.

horseshoe arch, Arabic arch, Moorish
arch A rounded arch whose curve is a little
more than a semicircle so that the opening at
the bottom is narrower than its greatest span.

horsing Same as outrigger shore.

horsing up Building up a desired plaster shape
with a running mold.

hortus 1. A pleasure garden or pleasure ground
of the ancients, similar in style and arrangement
to the garden of a modern Italian villa. 2. Any
type of garden in ancient Rome.

hose bib Same as sill cock.

jJllj^Jjl

horseshoe arch

hose cock Same as sill cock.

hose station The hose, nozzle, valve, and hose
rack that are combined to form part of a fire-
extinguishing system.

hose-stream test A test in which, after a
period of fire exposure, a wall partition or door is
subjected to the impact, erosion, and cooling
effects of a stream of water from a fire hose
directed first at the middle and then at all parts
of the exposed face.

hose thread A standard screw thread used for
attaching a garden hose; in the US has 12 threads
per inch on a % in. pipe size.

HOSP On drawings, abbr. for hospital.

hospice A resort for travelers which includes

lodging and entertainment.
hospital A building or part thereof used for the

medical, obstetrical, or surgical care of four or

more patients on a 24-hr basis.

3i$ufajL

hortu

518

hot spraying

hospital arm pull A handle for opening a hos-
pital door without the use of hands, by hooking
an arm over the handle.

hospital arm pull

hospital door A flush door (with or without a
glass light) large enough to permit the passage of
hospital beds, stretchers, etc.; usually equipped
with special hardware.

hospital frame A doorframe with terminated

stops.
hospitalium l.A guest chamber in a Roman

house. 2. A conventional entrance for strangers

in a dramatic performance.

hospital stop See terminated stop.

hospital window, hopper window A hop-
per light, 1 having a hopper, 2 on each side to

prevent drafts.

hospitium An inn or a place for the reception
of strangers.

hostel 1. A place of accommodation, com-
monly for people hiking or traveling by bicycle.
2. (Brit.) A residence hall at some universities.

hostry An inn.

hot-air furnace A heating unit enclosed in a
casing from which warm air is circulated through
the building in ducts by gravity convection or by
fans.

hot-air heating A system of heating by which
air, warmed above a fire chamber, is distributed
through ducts.

hot-air-seasoned Same as kiln-dried.

hot-applied sealant A compound which is
applied in a molten state and cured primarily at
ambient temperature.

hotbed A small low enclosure heated by fer-
mented manure or electric cables and usually

covered with glass; used for forcing bedding
plants and vegetables to grow out of season or for
protecting tender exotics.

hot-cathode lamp An electric-discharge lamp

which produces light by means of an arc dis-
charge; the cathodes are heated either by the
discharge or by an external source.

hot cement Cement which is at a high temper-
ature, usually owing to inadequate or insufficient
cooling after manufacture.

hot closet A closet adjacent to a fireplace or
oven; used for drying out damp clothes.

hot-dip galvanizing A protective coating
applied to ferrous metal by dipping in a bath of
molten zinc.

hot-driven rivet Any rivet that is preheated
before placement.

hotel A building in which lodging and other ser-
vices, often board, are provided primarily to tran-
sients and, less often, to permanent residents.

hot food table See steam table.

hot glue A glue which must be heated before
use. Also see hot-setting adhesive.

hothouse A greenhouse that is usually artifi-
cially heated; also see conservatory and orangery.

hot-laid mixture A mixture that is spread and
compacted in a heated condition.

hotmelt A thermoplastic material used as a
coating, sealer, or adhesive for wood and other
materials.

hot-melt sealant Same as hot-applied sealant.

hot mopped Said of a process that applies a
liquefied asphalt coating on a roof covering, 1 .

hot-pressing The pressure forming, between
heated platens, of plywood, laminates, particle-
board, fiberboard, etc.; usually requires ther-
mosetting resins and heat for curing.

hot-rolled finish The finish on a metal surface
obtained by rolling the metal while hot; results
in a dark, oxidized, relatively rough surface.

hot rolling The shaping of plate metal by
rolling very hot slabs of metal.

hot-setting adhesive An adhesive that requires
a temperature of 212°F (100°C) or higher to set it.

hot spraying A paint-spraying technique
which uses heat rather than solvent to lower
the viscosity of the paint; permits use of a lower

519

hot surface

spraying pressure and lessens the loss due to
overspray.

hot surface 1 . A surface which is very alkaline.

2. A surface which is highly absorbent. 3. A sur-

face at a high temperature.
hot-water blending See blending.
hot-water cylinder Same as hot-water storage

tank,
hot-water heater See domestic hot-water

heater.
hot-water heating Heating which utilizes a

system in which hot water circulates through

pipes, coils, and radiators.

hot-water heating system A heating system
in which water having supply temperatures lower
than 250°F (121°C) is used as a medium to con-
vey heat from a central boiler, through a piping
system, to suitable heat-distributing means.

hot-water heating system

hot-water recirculation system A hot-
water distribution system in which additional
piping and a return pump are incorporated so as
to return the unused hot water to the heater.
The water is recirculated through the heater to
compensate for system losses due to convection,
radiation, and conduction.

hot-water storage tank A tank that meets
code requirements for storing hot water. These
requirements depend on its size and pressure as
well as the authority having jurisdiction. The
volume of the tank usually is selected so that 60
to 80 percent of the volume of water in the tank

may be drawn off before the temperature drop of
the water in the tank is unacceptable.

hot-water supply A combination of equip-
ment and piping capable of providing a continu-
ous supply of hot water for domestic purposes,
usually between about 120° and 140°F (approx.
50° and 60°C).

hot-wire anemometer An anemometer which
measures the velocity of airflow by the effect of
the airflow on the temperature of a wire resistor
which is connected to an electrical circuit.

hot 'working The process of forming a metal

when its temperature is higher than its recrystal-

lization temperature.
hound's-tooth Same as dog's-tooth course.
hourdis Same as wattle-and-daub.
house l.A building or dwelling for human

residence. 2. A theater, as a legitimate house.

3. (Colloq.) The auditorium in a theater; the

audience space.

house-and-a-half Same as three-quarter Cape
Cod house.

house board A permanently connected elec-
tric switchboard in a theater, often controlling
only the houselights.

house connection Same as building sewer.

house curtain See act curtain.

housed Said of a piece or a member which is fit-
ted into another.

housed joint, dado joint A joint between
two wood members, usually at right angles; the
full thickness of the edge or end of one member is
inserted in a corresponding housing in the other.

housed joint

house drain 1 . Same as building drain. 2 . Same

as sanitary building drain,
housed stair Same as box stair.
housed string, housed stringer, housed

stair string Same as close string.

520

H-section

household All persons, including family mem-
bers and any unrelated persons, who occupy a
dwelling unit.

houselights Lights in an auditorium which
provide general illumination in the seating
areas, before and after performances and during
intermissions.

housemaid's sink See bucket sink.

housephone Same as closed-circuit telephone.

house pump A pump which fills a gravity tank
serving as the water supply for a building.

house raising See barn raising.

house sewer Same as building sewer.

house slant A T- or Y-shaped connection
between a sewer and a building sewer.

house tank 1 . A water storage tank for a build-
ing. 2. A gravity tank.

house tabs See act curtain.

house trap Same as building trap.

housing 1 . A notch or groove cut in one wood
member, usually to receive another wood mem-
ber, as in a housed joint; also called a trench.
2. A shelter or dwelling place, or a collection of
such places. 3. A niche for a statue.

housing, 1

housing project See project, 3.

housing unit A house, apartment, group of
rooms, or a single room occupied or intended for
occupancy as separate living quarters.

hovel 1 . A shed open at the sides and covered
overhead for sheltering livestock, produce, or
people. 2. A poorly constructed and ill-kept
house.

hoveling 1. Constructing a chimney by cover-
ing the top, leaving openings in the sides, or by

carrying up two sides higher than the other two.
2. A chimney so constructed.
Howe truss A truss having upper and lower
horizontal members, between which are vertical
and diagonal members; the vertical members of
the web take tension, and the diagonal members
are under compression.

Howe truss

Hoyer effect In prestressed concrete, the fric-
tional forces resulting from the tendency of the
tendons to assume their original diameter (i.e.,
their diameter before prestressing).

hp, HP l.Abbr. for horsepower. 2.Abbr. for
"high pressure."

H»pile 1. Any steel H-section used as a bearing
pile. 2. A steel H-beam used as a pile.

H»plan The basic plan of a building having the
shape of a capital letter H, with two open court-
yards.

HPS Abbr. for "high-pressure sodium."

HP»shape A standard structural hot-rolled
steel I-shaped column section; used for piles of a
specified category designated by the prefix HP,
placed before the size of the member.

HPT On drawings, abbr. for "high point."

HR On drawings, abbr. for "hour."

HRMS Abbr. for hot-rolled mild steel. Com-
pare with CRMS.

Hrt. In the lumber industry, abbr. for "heart."

Hrt.CC In the lumber industry, abbr. for "heart
cubic content."

Hrt.FA In the lumber industry, abbr. for "heart
facial area."

Hrt.G In the lumber industry, abbr. for "heart
girth."

H»runner In a ceiling suspension system, a
light metal member shaped like the letter H on
its side; one side of the H is attached to a chan-
nel, and the other (lower) side fits into the kerfs
of ceiling tiles. (See illustration p . 522.)

HSE On drawings, abbr. for house.

H-section Same as H-beam.

521

HTR

H-

HTR On drawings, abbr. for "heater."

hub 1 . The core of a building usually containing
one or more stairs and elevators, from which cor-
ridors radiate. 2. The part of a lock through
which the spindle passes to actuate the mecha-
nism. 3. A stake marking a theodolite position
in surveying. 4. See bell. 5. The thickened inner
portion of a gear or wheel, i.e., the portion clos-
est to the shaft.

HUD Acronym for the US Department of
Housing and Urban Development.

hue The subjective perception of color, e.g., red,
yellow, green, blue, purple, or some combination
thereof. White, black and gray colors possess no
hue.

hull An obsolete term for the framework of a
building.

humidification The process of adding mois-
ture to a volume of air; for example, to an air-
conditioning system.

humidifier A device for adding moisture to
air.

humidistat, hygrostat A regulatory device,
actuated by changes in humidity, used for the
automatic control of relative humidity.

humidity Water vapor within a given space or
environment.

humiture A combined measurement of tem-
perature and humidity; computed by adding the
temperature in degrees Fahrenheit to the
numerical value of the relative humidity and
dividing by 2; expressed to the nearest integral
value.

humus A brown or black material formed by
the partial decomposition of vegetable or animal
matter; the organic portion of soil.

hung ceiling Same as suspended ceiling.

hung scaffold A scaffold that is suspended
from the permanent structure of a building.

hungry, starved Descriptive of a paint film
which shows the minute detail of the background
on which it was applied, giving the appearance of
skimpiness.

hungry joint A masonry joint lacking suffi-
cient mortar to be weatherproof.

hung sash, hanging sash A sash hung on a
cord or chain at each side which is attached to a
balance or counterweight; moves in the vertical
direction.

hung slating 1. Slates covering a wall or other
vertical surface, rather than a roof (sloping) or
floor (horizontal). 2. Slates supported by wire
clips rather than by nails.

hung window A window containing one or
more hung sashes.

hurricane clip A mechanical device installed
at an eaves course of roof tiles to help prevent
the tiles from being lifted by wind.

hurricane test, dynamic test A dynamic
test for windows and curtain walls simulating the
forces and buffeting of a hurricane; both struc-
tural strength and water leakage are evaluated.

husk garland An ornament in the form of a
festoon; for example a festoon of nutshells.

hut 1 . A rough and plain habitation; often a
temporary shelter for soldiers. 2. A rustic cabin
or similar slight structure.

HVAC system Abbr. for heating, ventilating,
and air-conditioning system.

HVY On drawings, abbr. for "heavy."

HW On drawings, abbr. for "hot water."

HWRC system See hot-water recirculation
system.

HWY On drawings, abbr. for "highway."

hybrid Said of a plant produced by crossing two
distant varieties or species.

hybrid beam A fabricated metal beam com-
posed of flanges with a material of a specified
minimum yield strength different from that of
the web plate.

hybrid solar energy system A solar energy
system that combines the characteristics of two
separate heating systems, e.g., a solar energy
system and a conventional energy system.

522

hydraulic jump

hybrid solar system A combination of an
active solar energy system and a passive solar
energy system.

HYD On drawings, abbr. for "hydraulic."
hydralime Same as hydrated lime.

hydrant l.An apparatus for drawing water
directly from a main; consists of a hollow metal
cylinder provided with one or more nozzles to
which a hose may be attached, or with a valve or
faucet, used for supplying large quantities of
water. 2. See fire hydrant.

hydrate l.To combine with water or elements
of water. 2. Hydrated lime.

hydrated lime 1. Same as dry hydrate. 2. Quick
lime mixed with water, on the job, to form a lime
putty; slaked lime.

hydration 1 . The formation of a compound by
combining water with some other substance.
2. In concrete, the chemical reaction between
cement and water. 3. The chemical reaction by
which a substance (such as portland cement or
plaster) combines with water, giving off heat to
form a crystalline structure in its setting and
hardening.

hydraulically designed (sprinkler) system
A sprinkler system in which the pipe sizes are
calculated on the basis of the pressure loss to
provide a prescribed number of gallons of water
per square foot (liters per minute per square
meter) of floor area, or flow per sprinkler, with a
reasonable degree of uniformity over the area.

hydraulic cement A cement that hardens
under water. See cement, 2.

hydraulic collapse The collapse of thin pile
casing as a result of the hydrostatic pressure in
the ground.

hydraulic elevator An elevator powered by
the energy of a liquid under pressure in a cylin-
der which acts on a piston or plunger to move
the elevator car. Also see plunger hydraulic ele-
vator; roped hydraulic elevator.

hydraulic excavator A machine that uses
power from hydraulic cylinders to pull a bucket
at the end of a boom toward the machine
through earth or rock, then to raise the bucket,
permitting disposal of the spoil away from the
excavation.

hydraulic fill Fill that has been moved and
placed by flowing water.

hydraulic friction The friction that resists
the flow of a fluid along the piping or ductwork
in which it is conveyed and at obstructions.

hydraulic glue A waterproof glue.

hydraulic gradient l.The loss of head per
unit distance of flow. 2. In a drainage system, the
slope of a drainage line between the trap outlet
and vent connection.

hydraulic hydrated lime A dry, cementi-
tious, hydrated product obtained by calcining a
limestone containing silica and alumina to a
temperature short of incipient fusion; there is
sufficient calcium oxide to permit hydration, but
sufficient unhydrated calcium silicates to give
the dry powder its hydraulic properties.

hydraulic jack A jack operated by means of a
liquid, usually oil, acting against a piston; a small
force, applied by means of a lever attached to a
small piston, produces a very large force on a
large piston.

,> r ~~ 3 S»^

hydraulic jack

hydraulic jump A phenomenon at the tran-
sition from high to low velocity in the horizon-
tal pipe at the base of a vertical drain (i.e., a
drainage stack) where the flow of water changes
from a vertical to horizontal direction; results in
a discontinuity in flow at a short distance down-
stream from the base of the drainage stack. (See
illustration p . 524-)

523

hydraulic lift

Droinoge stack

Hydroulic jump in horizontal drom

Varies to approximately

10 limes die meter of stack

hydraulic jump

hydraulic lift Same as hydraulic elevator, esp.

one for raising automobiles.
hydraulic lime A hydraulic cementitious

product, produced by burning limestone con-
taining silica and alumina. Often classified as:
feebly hydraulic lime, moderately hydraulic lime,
and eminently hydraulic lime.

hydraulic monitor A device for directing a
high-pressure stream of water; used for a variety
of purposes, e.g., in cleaning a surface.

hydraulic mortar A mortar that is capable of
setting and hardening under water.

hydraulic pump A component unit in the
hydraulic system of a construction machine; the
prime mover that forces fluid to flow through
the system.

hydraulic radius The ratio of the cross-
sectional area of fluid flow through a pipe to the
wetted perimeter of the pipe.

hydraulics The branch of engineering which
treats the motion of fluids.

hydraulic splitter A device for cracking rock
or concrete by means of an expanding wedge
inserted in a hole or holes drilled in the material;
hydraulic power provides the force needed to
expand the wedge.

hydraulic spraying See airless spraying.

hydraulic test A test for pressure tightness in
a plumbing line, using water under pressure.

hydrologic soil group One of a classification
of soils that groups them according to their
water infiltration characteristics and their
potential runoff characteristics.

hydrophobic cement An unhydrated ce-
ment which has been treated to reduce its ten-
dency to absorb moisture.

hydropneumatic tank system A domestic
water supply system in which water is pumped

>.U'i'|.l'lW

hydropneumatic tank system

from the supply system into a pressure tank for
storage. Air in the tank is compressed by the water
entering the tank. As the pressure in the tank
increases, the pressure in the water distribution
system also increases, since it is fed from the tank.

hydrostatic head The pressure in a fluid at a
given point expressed in terms of the vertical
height of the liquid column above that point
which would produce the same pressure.

hydrostatic pressure The pressure equiva-
lent to that exerted on a surface by a column of
water of a given height.

hydrostatic strength Of a pipe, the capability
of withstanding internal pressure of a specified
magnitude under specified conditions.

hydrostatic test On a concrete pipe, a test to
determine capability of the pipe (or its joints) to
withstand internal hydrostatic pressure.

hygrograph A self-recording hygrometer.

hygrometer An instrument for measuring
humidity conditions (usually relative humidity)
of the surrounding air.

hygrometric expansion The expansion and
contraction of materials (particularly those of
organic origin) as they absorb or give off moisture.

hygroscopic Readily absorbing and retaining
moisture from the air.

hygrostat See humidistat.

hymn board A notice board in a church, on
which the numbers of hymns and psalms are
posted.

hypaethral, hypethral Describing a building
which is open, or partly open, to the sky.

hypaethron An open court or enclosure; a
place or part of a building that is roofless.

hyperbolic paraboloid roof A roof having
the shape of a geometric figure called a hyperbolic
paraboloid; the entire roof structure rests on only
two supports, giving it an appearance somewhat
resembling a bird in flight.

524

hyperthyrum A frieze and cornice arranged and
decorated in various ways for the lintel of a door.

hyphen A connecting link (for example, a cov-
ered walkway) between a large, centrally located
house and its dependencies or wings; the house
and its hyphens may be in a straight line or form
a curve. Also see five-part mansion.

hypobasis 1 . The lower base or the lowermost
division of a base. 2. A lower base which is
below a more important one.

hypocaust A central heating system of ancient
Rome; hot gases from a furnace were conducted
to rooms above, through a hollow floor and
through tile flues within walls.

hypogeum In ancient architecture, any under-
ground chamber or vault, esp. an underground
burial chamber.

hypophyge A depression of curved profile
beneath some feature, such as the hollow mold-
ing beneath some archaic Doric capitals.

hypopodium Same as hypobasis, 2.

hyposcenium In the ancient Greek theater, the
low wall beneath the front part of the logeion.

hypostyle hall 1. A large space with a flat roof
supported by rows of columns. Prevalent in

ancient Egyptian and Achaemenid architecture.
2. A structure whose roofing was supported,
within the perimeter, by groups of columns or
piers of more than one height; clerestory lights
sometimes were introduced.

hypotrachelium, gorgerin In some
columns, that part of the capital between the
termination of the shaft and the annulet of
the echinus, or the space between two neck
moldings.

hypostyle hall, 1: sectional view of Temple of Rameses II,
Thebes

hypotrachelium: h

hypsometric map See relief map.
Hz Abbr. for hertz.

525

This page intentionally left blank

IALD Abbr. for "International Association of

Lighting Designers."
IB Abbr. for I-beam.
I-bar Steel or iron bar whose cross section is

similar to an I.
I»beam A rolled or extruded structural metal

beam having a cross section resembling the

letter I.
ICC See International Code Council.
ICE Abbr. for the "Institution of Civil Engi-
neers," London.
ICEA Abbr. for "Insulated Cable Engineers

Association."
ice dam A buildup of snow and ice at the eaves

of a sloping roof.

TRAPPED WATER

ice dam

icehouse A building for storing ice that is usually
cut during the winter from frozen lakes, rivers, or
ponds for use later in the year; often located in a
shady area; usually has overhanging eaves and
thick exterior walls that are packed with thermal
insulation and painted white to reduce the absorp-
tion of heat radiated from the sun.

ichnography The tracing of ground plans; the
representation of a ground plot.

ICI Abbr. for "International Commission on
Illumination."

iconostasis A screen in a Greek Orthodox
church, on which icons are placed, separating
the chancel from the space open to the laity.

ID On drawings, abbr. for "inside diameter."

IDSA Abbr. for "Industrial Designers Society of
America."

IEE Abbr. for "Institution of Electrical Engi-
neers," London.

IEEE Abbr. for "Institute of Electrical and Elec-
tronics Engineers."

IERI Abbr. for "Illuminating Engineering
Research Institute."

IES l.Abbr. for the "Illuminating Engineering
Society of North America." 2. Abbr. for
(British) "Illuminating Engineering Society."

IF Abbr. for "inside face."

igloo, iglu A hemispherical shell, built by Eski-
mos of blocks of ice or packed snow as a tempo-
rary dwelling for a single family; usually about 10
to 15 feet (3 to 4-5 m) in diameter at its base,
with the floor often partially below the sur-
rounding terrain. Daylight within was provided
by one or more blocks of relatively transparent
freshwater ice, or by an opening covered with a
piece of translucent seal intestine. Entry was
usually along a domed passageway.

igneous rock A class of rock formed by change
of the molten material to the solid state; gener-
ally termed granite if coarse-grained.

ignitability The ease with which ignition of a
material can be initiated.

ignition The initiation of combustion, as evi-
denced by flame, glow, or explosion.

ignition source A heat source having suffi-
cient energy to initiate combustion of a material.

ignition temperature Of a material, the mini-
mum temperature required to initiate combustion.

527

I-house

I»house A side-gabled house, usually one-and-
a-half or two stories high, one room deep, and
two rooms wide; the two rooms usually have an
entrance hall between them containing a cen-
tral stairway.

IHVE Abbr. for "Institution of Heating and
Ventilating Engineers."

IIC Abbr. for impact isolation class.

I»joist A structural steel member having a cross
section that resembles the capital letter I.

ILI Abbr. for "Indiana Limestone Institute."

illite A clay mineral, a hydrous silicate of potas-
sium, aluminum, iron, and magnesium; swells
considerably on wetting and shrinks proportion-
ately on drying.

illuminance The density of luminous power,
also called "illumination." One lumen of lumi-
nous flux, uniformly incident on 1 square foot of
area, produces an illuminance of 1 footcandle; in
SI units, one lumen of luminous flux, uniformly
incident on 1 square meter of area, produces an
illuminance of 1 lux.

illuminated sign A sign designed or arranged
to emit or reflect light from an attached artificial
source.

illumination The luminous flux density inci-
dent on a surface, i.e., the luminous flux per
unit area; usually expressed in lumens per square
foot or footcandles, and lumens per square
meter or lux.

illumination level The quantity of light that
illuminates a surface; measured in foot candles
or in lux.

illumination meter, Brit, illumination pho-
tometer An instrument for measuring the
illumination on a surface; usually consists of bar-
rier-layer cells connected to a meter calibrated
directly in a set of illumination units.

illumination photometer (Brit.) See illumi-
nation meter.

ILLUS On drawings, abbr. for "illustrate."

ilmenite A mineral which is commonly used as
an aggregate in high-density concrete; also
called iron titanate.

image Any representation of form or features,
but esp. one of the entire figure of a person; a
statue, effigy, bust, relief, intaglio, etc.

image

imaret A type of hostelry for the accommoda-
tion of Muslim pilgrims and other travelers in
the Turkish empire.

imbow Same as embow.

imbrex l.A tile, semicircular in shape, which
fits over the joints in a tile roof. 2. One of the
scales in ornamental imbrication.

imbricate To overlap in regular order, as shin-
gling, tiles, etc.

imbrication Overlapping rows of shaped tiles
or shingles that resemble overlapping fish scales;
also see contre-imbrication.

imbrication

IMC Abbr. for intermediate metallic conduit.

IMechE Abbr. for "Institution of Mechanical
Engineers."

immersion heater A heater in which the
electric heating element, submerged in a water
tank, is controlled by a thermostat built into the
tank or in contact with the water.

immersion vibrator A vibrator which is
inserted in the fresh concrete during the agita-
tion, 1 process.

528

impervious

impact factor In structural design, that factor
by which a static load effect must be multiplied
in order to find the increment of the dynamic
effect of applying the load other than statically.

impact insulation, impact isolation 1.
The use of structures and materials designed to
reduce the transmission of impact noise in a
building. 2. The degree by which transmission of
impact noise is reduced by use of materials and
structures for that purpose.

impact insulation class (IIC) A single-
number rating used to compare and evaluate the
performance of floor-ceiling constructions in
isolating impact noises.

impact load The dynamic effect on a structure,
either moving or at rest, of a forcible momentary
contact of another moving body.

impact noise Sound generated by impact and
carried through a structure; typically, footsteps,
the slamming of a door.

S03E

"4.

" "pra ter an «f»
•ra~ii hi

transmission of impact noise

impact noise rating (INR) A rating,
expressed by a single number, which is a rough
measure of the effectiveness of a floor construc-
tion in providing isolation against the noise of
impacts; in general, the higher the number, the
greater the effectiveness.

impact resistance The resistance of surface
(or a material or product) to a shock, such as a
hard blow.

impact strength, impact energy The

amount of energy required to fracture a material;
a measure of the material's resistance to mechan-
ical shock.

impact test A method of determining the resis-
tance of a specimen to fracture upon the appli-
cation of a dynamic physical shock.

impact ■wrench A wrench, driven pneumati-
cally or electrically, which produces a series of
impulsive torques.

impages l.The broad transverse band on a
door, which stretches from stile to stile and
divides the panels horizontally from one
another; a door rail. 2. The border or framework
of a panel of a door.

impasto In painting, the thick laying of pigments.

impedance In alternating-current electric cir-
cuits, a quantitative measure of the opposition
to the flow of current upon the application of
voltage; measured in ohms.

impeller The rotating member in a pump con-
sisting of a disk with vanes attached to it;
moves liquid by accelerating the liquid radially
outward.

Rotation

impending slough The consistency of shot-
crete which contains the maximum amount of
water that can be used without flow or sag after
placement.

imperfect arch A diminished arch.

imperial staircase See double-return stair.

impermeable Said of a soil whose particles are
so closely spaced that the passage of water is
either prevented or very slow.

impervious In ceramics, that degree of vitrifica-
tion evidenced visually by complete resistance to
dye penetration; generally signifies zero absorption

529

impervious cover

of water, except for floor and wall tile, which may
absorb up to 0.5% water.

impervious cover A ground surface that
resists the infiltration of water, thereby resulting
in a high rate of water runoff.

impervious soil A fine-grained soil, such as
clay, having pores too small to permit water to
pass except by slow capillary creep.

impetus The span of a building, roof, or arch.

IMPG On drawings, abbr. for "impregnate."

implied indemnification An indemnifica-
tion which is implied by law rather than arising
out of a contract.

impluvium In ancient Roman dwellings, a cis-
tern set in the atrium or peristyle to receive water
from the roofs.

impluvium, A

imposed load All loads, exclusive of dead
load, that a structure is to sustain.

impost 1. A masonry unit or course, often dis-
tinctively profiled, which receives and distrib-
utes the thrust at each end of an arch. Also see
abutment, springer. 2. A vertical member in a
gemel or double window taking the place of a
mullion; an integral mullion.

impost block, dosseret, supercapital A
transitional member, often tapered, placed
above a column capital to receive the thrust of
vaults or arches.

impregnated cloth A cloth impregnated with
resin, varnish, shellac, etc.

impost, 1

impregnated timber Timber into which a
flame retarder, insect poison, and/or fungicide
has been forced under pressure.

impregnation The process of adding chemical
preservatives, resin, or fire retardants to wood
under pressure. Also see Bethell process.

improved land Land which has been pro-
vided with water, sewers, sidewalks, and other
basic facilities for residential or industrial devel-
opment.

improved 'wood Wood impregnated with resin
and cured with heat and pressure to increase its
strength, durability, and moisture resistance.

improvement A structure or public utility or
any other installation or physical change made
in a property to increase its value and utility or
to improve its appearance.

in. Abbr. for "inch."

inactive leaf, inactive door That leaf of a
pair of doors which does not contain a lock, and
to which the strike plate is fastened to receive
the latch or bolt of the active leaf; usually it is
fixed in a closed position by bolts at the top and
bottom of the door.

530

inches of mercury

in»and-out bond In masonry, a bond, 6 formed
by headers and stretchers alternating vertically,
esp. when formed at a corner, as by quoins.

in-and-out bond

in antis See anta and distyle in antis.

in-bank measure Measurement of the vol-
ume of ground before it has been excavated.
inbark See bark pocket.

inbond In masonry, bonded or forming a bond
across the thickness of a wall; composed largely
or entirely of headers or bond-stones.

INC l.On drawings, abbr. for "incorporated."
2. On drawings, abbr. for "incoming."

Inca architecture The architecture of the
Inca Empire in Peru from the 12th cent, until
the Spanish conquest in the 16th cent., particu-
larly fortified towns with massive stonework.

incand Abbr. for "incandescent."

incandescence The emission of visible light
as a result of heating.

incandescent daylight lamp An incandes-
cent lamp having a blue-green glass bulb which

makes the emitted light whiter by absorbing part
of the yellow and red light; approximately 35%
less efficient than the standard incandescent lamp.

incandescent direct-light lamp, bird's-eye
lamp An incandescent lamp, usually with a PS-
or A-shaped bulb which is silvered from the maxi-
mum diameter to the base, leaving a clear or
frosted hemispherical region opposite the base end.

incandescent lamp, incandescent filament
lamp A lamp from which light is emitted
when a tungsten filament is heated to incandes-
cence by an electric current.

FiL a ME NT-

LEAD -IN WIRES

BASE

incandescent lamp

incandescent lamp base See lamp base.
incandescent lamp filament See filament,
incandescent lighting fixture A luminaire,

usually complete with incandescent lamp(s),
socket(s), reflector, and often with a louver or
diffusing medium.

incandescent special-service lamp One of
a class of lamps with special properties to meet
particular needs, such as vibration service lamps,
rough service lamps, cold service lamps, etc.

incasement Same as encasement.

in cavetto The reverse of relief, differing from
intaglio in that the design is impressed into plas-
ter or clay.

incavo The hollowed or incised part of an
intaglio.

incense cedar A close-grained wood having a
fragrant resinous odor; highly resistant to mois-
ture.

incertum opus See opus incertum.

inches of mercury A unit used as a measure
of pressure; equal to the pressure exerted by a
column of mercury 1 inch (2.54 cm) high;
equivalent to a pressure of 3386.4 newtons per
square meter.

531

inch of water

inch of water A unit of pressure equal to the
pressure exerted by a column of liquid water 1 in.
high at a temperature of 39.2°F (4°C).

inch stuff Building materials having a nominal
1-in. (2.5-cm) thickness, although actually mea-
suring less.

INCIN On drawings, abbr. for incinerator.

incinerator An apparatus in which solid, semi-
solid, or gaseous combustible wastes are ignited
and burned.

incipient decay Early stages of decay in wood
in which the color has changed but the strength
and hardness have not yet been affected.

incise 1 . To decorate by cutting or indenting a
surface, as ceramic ware. 2. To perforate the sur-
face of timbers, poles, posts, etc., to increase
penetration of wood preservatives.

INCL On drawings, abbr. for "include."

inclination The angle which a line or surface
makes with the vertical, horizontal, or with
another line or surface.

incline A sloping surface, i.e., neither horizon-
tal nor vertical; a slope.

inclined-axis mixer, high-discharge mixer

A truck equipped with a body for mixing con-
crete; consists of a revolving drum which rotates
about an axis inclined to the bed of the truck
chassis.

inclined end post An inclined compression
member at the end of a truss.

inclined lift A powered passenger elevator,
installed on a stairway; used to raise or lower a
person from one floor to another.

inclined shore A raking shore.

inclinometer A device for measuring the hori-
zontal movement within a soil mass.

inclusion The presence of foreign matter in a
finished material.

incombustible Same as noncombustible.

increaser In plumbing, a tapered coupling for
joining a pipe or conduit to another of larger size.

incrustation l.The deposition of materials on
the interior of pipes, vessels, or equipment from
chemicals in the conveyed liquid. 2. A decora-
tive skin or coating of rich materials applied
over commoner construction.

IND On drawings, abbr. for "industrial."

increaser

indemnification A contractual obligation by
which one person or organization agrees to
secure another against loss or damage from spec-
ified liabilities.

indent 1. The gap left by the omission of stone,
brick, or block units in a course of masonry; used
for bonding future masonry. 2. In a wall of a
church, a space hollowed out of stone to receive
a brass effigy.

indented bar A type of deformed bar.

indented bolt A type of anchor bolt with sur-
face indentations to increase its grip.

indented joint A joint used in joining timbers
end to end; a notched fishplate is attached to
one side of the joint to fit into 2 corresponding
notches in the joined timbers; the entire assem-
bly is fastened with bolts.

indented molding, indenting A molding
with the edge toothed or indented in triangular
tooth-like shapes.

indented molding

indented wire A type of wire having surface
indentations to improve its bond when used in
concrete reinforcement or for pretensioning
tendons.

independent-pole scaffold Same as double-
pole scaffold.

index of key words Part Four of the uniform
system for construction specifications, data fil-
ing, and cost accounting.

532

indirect waste pipe

index of plasticity See plasticity index.

Indian architecture The architecture of the
Indian subcontinent, originally a timber and
mud-brick architecture of which nothing sur-
vives. Early Buddhist monuments, chaitya halls,
stupa rails, and toranas clearly imitate wood
construction, and timber buildings appear on
relief representations. All surviving architecture
is of stone, using exclusively a structural system
of post and lintel, brackets, and corbels. The
basically simple Indian architectural forms are
generally obscured and overwhelmed by a rhyth-
mical multiplication of pilasters, cornices, mold-
ings, aediculae, roofs, and finials, and an
exuberant and sensuous overgrowth of sculptural
decoration.

Indian architecture

Indian oak See teak.

Indian shutters In many American colonial
houses, sliding panels placed along the inner
walls whose purpose may have been to increase
protection against Indian arrows.

indicator bolt A door bolt which indicates
whether a water closet is vacant or occupied.

indicator button A device incorporated in
the lock of a door of a hotel room to indicate
whether or not the room is occupied.

indicator light, indicator lamp Same as
pilot light, 1 .

indicator valve A valve whose design includes
some mechanism to show that the device is open
or closed.

indigenous Said of a plant or tree which is
native to the area in which it is grown.

indirect cost On a building project, those costs
that are attributed to overhead, as opposed to
any specific task or component; for example, the
cost of supervisory personnel in the site office.

indirect drain pipe Same as indirect waste pipe.

indirect expense Overhead expense; expense
indirectly incurred and not directly chargeable
to a specific project or task.

indirect footlight A footlight unit with light
sources placed so that the light rays strike the
area to be illuminated from a reflecting surface
rather than directly.

indirect heating See central heating.

indirect lighting Lighting from luminaires
which distribute 90% to 100% of the emitted light
upward so that illumination is provided primarily
by reflected light rather than by direct light.

indirect luminaire A luminaire which emits
90% to 100% of its total output above a hori-
zontal plane through it.

indirect solar water heating system A solar
water heating system employing a closed circula-
tion loop through a heat exchanger; the fluid
which flows through the solar collector is isolated
from contact with other fluids in the system.

indirect system A heating, air-conditioning,
or refrigeration system in which a fluid is circu-
lated to the space or material to be heated or
cooled, or is used to heat or cool air which is so
circulated; the fluid (such as air, water, or brine)
is heated or cooled by products of combustion,
by electric heating, or by a refrigerant.

indirect waste pipe A waste pipe which does
not connect directly with the building-drainage

FLOOR

FLOOR
DRAIN

W^ 3

indirect waste pipe

533

indirect water heater

system, but discharges into it through a properly
trapped fixture or receptacle.

indirect water heater A water heater in
which the temperature of the water in the sys-
tem is increased by means of a remotely-located
heat exchanger.

individual sewage-disposal system A sys-
tem of sewage treatment tanks and disposal facili-
ties, designed for a single building, establishment,
or lot, not served by a public sewer.

individual vent Of a plumbing fixture, a pipe
which vents a fixture drain and which is con-
nected to the main vent above it.

MAIN V£ NT
VtNT PIPE

WASTE PIPE

individual vent

individual water supply A supply other than
an approved public water supply which serves one
or more families.

indoor air quality The quality of air inside a
building; deemed to be acceptable by ASHRAE
if it contains no contaminants at harmful con-
centrations, and if at least 80% or more of the
people in the building who breathe this air do
not express dissatisfaction with it.

induced draft The forced movement of air or
gases caused by the suction created by the inlet
side of a fan.

induced-draft boiler A boiler system having
a power-operated fan at its discharge end; the
fan draws air through the burner and boiler, con-
veying the products of combustion to the atmo-
sphere through a short chimney.

induced-draft water-cooling tower A water-
cooling tower having one or more fans located in
the saturated air stream leaving the tower.

induced siphonage Siphonage of water from a
fixture trap (i.e., the drawing away of water that
forms a trap seal); usually due to an improperly
installed vent pipe. As a result, when another fix-
ture on the same vent pipe discharges, siphonage
may be induced.

induction 1 . In air conditioning, the entrain-
ment of air in a room by the flow of a stream of
primary air from an air outlet. 2. The process by
which current in one conductor induces an elec-
tric current in a nearby conductor.

induction brazing A brazing process in which
the required heat is obtained from the resistance
of the work to an induced electric current.

induction heating In piping, the heat treat-
ment of completed welds by the heat generated
by the use of induction coils around the piping.

induction motor An alternating-current motor
having its primary winding, on one member
(which is usually the stator), connected to the
source of electric power; a secondary winding on
the other member (usually the rotor) carries the
induced current.

induction soldering A soldering process in
which the required heat is obtained from the resis-
tance of the work to an induced electric current.

induction welding A welding process in which
coalescence is produced by the heat obtained from
resistance of the work to an induced electric cur-
rent, with or without the application of pressure.

industrial area Any area devoted predomi-
nantly to manufacturing.

industrialized building system A building
system of mechanized production design in
which the subsystems and components have
been integrated into an overall process, utilizing
factors of planning, design, programming, pro-
duction, transportation, and on-site assembly
techniques. Also see systems building.

industrial design The art of utilizing the
resources of technology to create and improve
products and systems which serve human beings,
taking into account factors such as safety, econ-
omy, and efficiency in production, distribution,
and use. Such design may be expressed partly in
external features, but predominantly in integra-
tive structural relationships, responding to the
perennial human need for meaningful form.

industrial lift A nonportable, power-operated
hoisting and lowering mechanism for raising or

534

information outlet

lowering material vertically, operating entirely
within one story of a building.

industrial occupancy 1. Use of a building for
the manufacture of products of any kind. 2. Use of
a building for processing, assembling, mixing,
packaging, finishing or decorating, repairing, and
similar operations. Also see general industrial
occupancy, high-hazard industrial occupancy,
special-purpose industrial occupancy.

industrial park A planned industrial or
technologically-based district of a city; usually
intended for light manufacturing, industrial usage,
research, or for warehousing; often located in open
land near the city or in a renovated urban area.

industrial tubular door A door constructed
from tubular steel with locked seams; the corners
are welded and all joints are ground smooth; the
door panels consist of one or two sheets securely
fastened to stiles and rails.

industrial waste A waterborne waste resulting
from an industrial process; differs in composition
from domestic sewage wastes.

industry standard specification In the
construction industry, a specification based on
codes, technical reports and disclosures, or on
test procedures and results that have been shown
to be of proven use and general acceptance.

inelastic behavior Deformation of a material
that does not disappear on removal of the force
that produced it.

inert base A paint base which does not provide
hiding, color, or drying properties. Its main func-
tion is to provide solids, usually at low cost.

inert filler In paints, same as inert base.

inertia block A concrete block which serves as
a base for mechanical equipment such as fans or
pumps; the block is mounted on a resilient sup-
port to reduce the transmission of vibration to
the building structure.

Pump baseplate

Vibration

iWaiors

Lifting
screw

Spring
isolator

Concrete
foundation

pump on an inertia block

Floor

inertia block

inert pigment 1. A nonreactive pigment. 2. An
extender pigment, used to provide solids and bulk.

infant school (Brit. ) A form of primary school
which gives instruction to 4- to 7-year-old chil-
dren in preparation for grammar school.

infilling Material used to fill the spaces, within
a frame, between structural members of a build-
ing; provides additional thermal insulation, fire
resistance, and stiffness. Also see fill insulation.

infiltration 1 . The seepage or flow of air into a
room or space through cracks around windows,
under doors, etc. 2. In a concrete sewer pipe laid
in soil, the volume of groundwater that enters
the pipeline system.

infiltration basin An open-surface storage
area for water having no outlet other than an
emergency spillway.

infirmary A place which provides uncompli-
cated medical and nursing care, usually for resi-
dents or members of an institution, such as a
school.

inflammable Same as flammable.

inflatable gasket A gasket whose effective-
ness depends on a seal provided by inflation with
compressed air.

inflatable structure See pneumatic structure.
inflected arch Same as inverted arch.
inflection point Same as point of inflection.

inflow The volume of any type of water entering
a sewer pipe from outside sources not included
under infiltration.
INFO On drawings, abbr. for "information."
information outlet In a telephone wiring sys-
tem in a building, a connection device designed
for a fixed location (usually on a wall) in which
telephone wiring terminates; the outlet contains
a female jack to receive a male plug that is
inserted into it. Such outlets are used to connect

535

infrared

a telephone, FAX, telephone answering machine,
etc., to a telephone line.

infrared That region of the electromagnetic
spectrum at wavelengths immediately above the
visible spectrum; the heat in this region of the
spectrum which is generated by a light source
usually is undesirable (since it represents a loss
in efficiency), but such heat is used in industrial
applications for drying, baking a surface, etc.

infrared drying Drying by use of infrared
lamps to decrease drying time.

infrared emittance See emittance.

infrared lamp An incandescent lamp having a
higher percentage of the radiant power in the
infrared region than a standard incandescent
lamp; has longer average life owing to the lower
filament temperature; may have a red glass bulb
to reduce the radiated visible light.

infrasound Acoustic oscillations having a fre-
quency below the low-frequency limit (approxi-
mately 16 Hz) of audible sound.

infrastructure The basic equipment of a build-
ing that is necessary for the building to serve its
intended function.

in-glaze decoration A ceramic decoration
applied on the surface of an unfired glaze and
then matured with the glaze.

ingle A fireplace; a hearth.

inglenook A fireplace hearth in a corner of a
room; often provided with seating; same as
chimney corner.

ingot A mass of molten metal which has been
poured into a mold to solidify; it differs from a
casting in that it requires rolling or forging to
become a finished or semifinished product.

ingot iron Same as mild steel, 1.

ingrown bark, inbark See bark pocket.

inhibiting pigment A pigment (such as lead
and zinc chromate, zinc oxide, red lead, zinc
metal, and barium metaborate) added to paint to
inhibit or prevent rust and corrosion of metals or
the formation of mildew.

inhibitor A substance added to paint to retard
drying, skinning, mildew growth, etc. Also see
corrosion inhibitor, inhibiting pigment, drying
inhibitor.

initial backfill The material used in filling a
trench from the top of the bedding to a speci-

fied height above a pipe which is laid in the
trench.

initial drying shrinkage The difference
between the initial length of a moist concrete
specimen and the length of the specimen after it
is first dried and has reached a stable length; usu-
ally expressed as a percentage of the initial moist
length.

initial grade Same as natural grade.

initial prestress The prestressing stress (or
force) applied to prestressed concrete at the time
of stressing.

initial rate of absorption See absorption rate.

initial set 1 . A degree of stiffening of a mixture
of cement (or concrete or mortar) and water less
than final set; generally stated as the time
required for cement paste to stiffen sufficiently
to resist the penetration of a weighted test-
needle. 2. Of a mastic compound, adhesive, or
coating, the stage in curing or drying when the
surface has become sufficiently firm to be
unmarked when touched with the finger.

initial setting time The time required for a
freshly mixed cement paste, mortar, or concrete
to achieve initial set.

initial shrinkage The drying shrinkage that
takes place during the setting of a cement, con-
crete, paste, mortar or the like; caused by the
evaporation of moisture.

initial stress Stress in a prestressed concrete

member before any loss of stress occurs.

injection burner A gas burner that employs a
gas jet to thrust air for combustion into the
burner and mix it with the gas.

injection molding A molding procedure
whereby a heat-softened plastic material is
forced from a cylinder into a relatively cool cav-
ity which gives the article the desired shape.

inlaid parquet Inlaid wood flooring, often
arranged in simple geometric or decorative pat-
terns.

inlay, intarsia, marquetry 1. A shaped piece
of one material embedded in another as part of a
surface ornamentation. 2. Such ornamentation
as a whole. Also see encaustic tile.

in-line centrifugal fan A centrifugal fan
which is specially designed to be connected to
the ductwork in direct line with the discharge
from the fan housing.

536

inserted tenon

$3&

inlay of black and white marble

in-line pump A pump supported directly by
the system piping (i.e., the piping carries the
weight of the pump); usually mounted vertically
to save floor space, with its weight centered over
the piping.

inn 1. A place which provides eating and drink-
ing, but no lodging, for the public; a tavern. 2. A
hotel. 3. A student hostel or residence. 4. A hos-
pice.

inner bailey A courtyard within the central
defenses of a castle.

inner bailey

inner bead Same as inside stop.

inner casing See inside casing.

inner court l.An open, unoccupied space
surrounded on all sides by the exterior walls of a
building or structure. 2. An open, unoccupied
space surrounded by the exterior walls of a
building and an interior lot line of the same
premises.

inner hearth That part of a hearth contained
within a fireplace; the back hearth.

inner sanctum A most sacred place.

inorganic material A material which is com-
posed of minerals, or made from minerals; not
animal or vegetable in origin.

inorganic silt See silt.

inosculating column Same as clustered
column.

inpaint To renew damaged areas on paintings
or painted surfaces by repainting.

INR Abbr. for impact noise rating.

inrush current See lamp inrush current.

INS On drawings, abbr. for "insulate."

insanitary Injurious to health or contrary to
sanitary principles.

inscription Lettering, often monumental, dec-
orating architecture inside or out.

insect screen, window screen A very light
woven-wire used to prevent insects from flying
through open windows or doors.

insect wire screening A woven wire screen-
ing having a mesh small enough to provide pro-
tection against insects.

insert l.A nonstructural repair to correct an
appearance defect in laminated timber. 2. An
inlay of wood veneer, a patch, or a plug used to
fill holes in plywood. 3. See patch, 2.

insert card reader A device for providing
access to a locked door. The cardholder must
insert a card (usually having a magnetic strip)
into the device to unlock the door.

inserted column A column which is partially
inserted in a wall; an engaged column.

inserted grille A grille that is fabricated sepa-
rately for mounting in a prepared opening in a
door.

inserted tenon See false tenon.

537

inset dormer

inset dormer A dormer that is partially set
below a sloping roof, unlike the usual dormer
that projects entirely above the sloping roof.

inset porch Same as integral porch.

inside-angle tool A float used in shaping inside
angles in plastering and masonry.

inside caliper A type of caliper which is espe-
cially designed for measuring the inside diameter
of a cylinder or the distance between shapes.

inside casing, interior casing The inside trim

around the interior of a door or window frame.

OUTSIDE
CASING

INSIDE
CASING

inside casing

inside chimney Same as interior chimney.
inside corner molding A molding covering
the joint at the internal angle of two intersect-

inside corner molding

ing surfaces, as the metal coves used with plastic
laminates, etc.

inside-door lock, room-door lock A lock
having a spring bolt (operated by a knob) and a
dead bolt operated by a key.

inside finish See interior trim.

inside glazing External glazing which is installed
from inside the building. Also see internal glazing.

inside lining See inside casing.

inside micrometer A micrometer especially
designed for the accurate measurement of the
inside diameter of a cylinder, such as a pipe.

inside stop, bead stop, inner bead, stop
bead, window bead, window stop In a
double -hung window, a strip of wood fixed to the
casing, along the inner edge of the inner sash;
restricts the motion of the sash to a vertical plane.

inside thread The thread on the inside of a
pipe, fitting, or machine screw.

inside trim l.Any trim on the interior of a
building. 2. Trim around door or window open-
ings; also called inside casing.

in situ In place, as in cast-in-place concrete.

in situ concrete See cast-in-place concrete.

insoluble residue That portion of an aggre-
gate or cement which is not soluble in diluted
hydrochloric acid.

inspection 1. Examination of work completed
or in progress to determine its compliance with
contract requirements. 2. Examination of the
work by a public official, owner's representative,
or others. 3. The process of measuring or check-
ing materials, workmanship, or methods for con-
formance with quality controls, specifications,
and/or standards.

inspection chamber A shallow manhole.

inspection eye Same as cleanout, 1.

inspection fitting Same as cleanout, 1.

inspection junction Same as cleanout.

inspection list A list of items of work to be
completed or corrected by the contractor.

inspector 1. See building inspector. 2. See owner's
inspector. 3. See resident engineer.

instability In a structure, the sudden loss of stiff-
ness that limits its load-carrying capability, and
in some cases results in the structure's failure.

instal Abbr. for "install" or "installation."

538

insulating glass unit

instantaneous-type water heater A heater
in which there is an exceedingly rapid increase
in water temperature as the water flows through
tubes surrounding an electric heating coil; best
suited for applications requiring a continuous
flow of hot water. Must be used with care when
the demand is low because accurate temperature
control at low flow rates usually is poor.

Temperature -limiting
thermostat

Gas supply

instantaneous-type water heater

instant lock A lock which is actuated auto-
matically (by a spring) as the door is closed.

instant-start fluorescent lamp A fluores-
cent lamp designed to be started by high voltage
without preheating of the electrodes; usually has
single-pin base connections; a slim-line lamp.

InstCES Abbr. for "Institution of Civil Engi-
neering Surveyors."

Institute of Electrical and Electronic Engi-
neers (IEEE) A professional organization of
electrical engineers having its headquarters in
Piscataway, NJ 08855.

Institution of Electrical Engineers (IEE)

A professional organization of electrical, elec-
tronic, and systems engineers having its head-
quarters at Savoy Place, London WC2R OBL.
Institution of Structural Engineers A pro-
fessional organization of structural engineers
having its headquarters at 1 1 Upper Belgravia
Street, London 5W1 8BH.

institutional occupancy The use of a build-
ing for the medical treatment or care of persons
suffering from illness or infirmity; for the care of
infants, convalescents, or aged persons; or for
penal or corrective purposes.

instructions to bidders Instructions con-
tained in the bidding requirements for preparing
and submitting bids for a construction project.
Also see notice to bidders.

instructions to tenderers Same as notice to
bidders.

insul Abbr. for "insulate" or "insulation."

insula l.In Roman town planning, a block of
buildings surrounded by streets. 2. A Roman
apartment house occupying such a block.

insulated flange A coupling used in metal
pipes to interrupt the electrical transmission
path that would otherwise exist.

insulating board See board insulation.

insulating cement l.A combination of
hydraulic-setting cement (or other bonding
ingredient) and a loose-fill insulation, mixed to
a workable putty-like consistency; used in insu-
lation applications to fill voids, joints, etc. 2. A
mixture of dry granular, fibrous, flaky, or pow-
dery materials that develops a plastic consis-
tency when mixed with water, and when dried
in place; forms a coherent covering that pro-
vides substantial resistance to heat transmission.

insulating concrete Concrete having low
thermal conductivity; used as thermal insulation.

insulating fiberboard Fibrous insulating
material (such as wood, cane, or other vegetable
fibers) and binder, formed into a board. Manu-
factured units vary widely in thickness, linear
dimensions, density, thermal resistance, and
mechanical strength.

insulating form board Insulation board used
as a permanent form for poured-in-place gypsum
or lightweight-concrete roof decks.

insulating glass Two sheets of glass that are
assembled and sealed around their edges as a single
unit; the space between the glass sheets is dehy-
drated or filled with a gas. Such a unit is effective
in reducing the transfer of heat through it.

insulating glass unit A panel of double glaz-
ing which is sealed around its periphery; provides
increased resistance against the transmission of
heat and sound.

539

insulating material

insulating material See electrical insulation,
thermal insulation.

insulating oil A type of oil used within the
enclosure of a transformer, switch, or other elec-
tric device, for insulating and cooling purposes.

insulating plasterboard See foil-backed gyp-
sum board.

insulating strip An expansion strip.

insulating varnish A varnish used as insula-
tor on wire or electric circuits.

insulation See electrical insulation, sound insula-
tion, thermal insulation.

insulation board See board insulation.

insulation lath Gypsum lath having an alu-
minum foil laminated to its back in order to pro-
vide a vapor barrier and reflective insulation
against thermal losses.

insulation resistance The resistance to the
flow of current through an insulating material
resulting from an impressed direct voltage; usu-
ally expressed in ohms.

insulation test A test to determine the resis-
tance of electrical insulation to the flow of direct
current.

insulator See electrical insulator.

insurance See: builder's risk insurance; com-
pleted operations insurance; comprehensive
general liability insurance; contractor's liability
insurance; employer's liability insurance; liabil-
ity insurance; loss of use insurance; owner's lia-
bility insurance; professional liability insurance;
property damage insurance; property insurance;
public liability insurance; special hazards insur-
ance; steam boiler and machinery insurance;
workmen's compensation insurance.

INT l.On drawings, abbr. for "intake." 2. On
drawings, abbr. for "interior." 3. On drawings,
abbr. for "internal."

intaglio 1. Incised engraving, as opposed to
carving in relief. 2. The work producing such an
object.

intaglio rilevato See sunk relief.

intake An opening through which water or air
(or any other fluid) enters a system, chamber,
plenum, pipe, or machine. Also see outside-air
intake.

intake belt course A projecting course of
masonry at a level where the wall is reduced in
thickness.

intake door A door that penetrates a wall
enclosing a refuse chute and through which waste
material is deposited directly into the chute.

intake door

intarsia Mosaic inlay, especially a form of wood
inlay.

integral frame A type of doorframe; the trim,
backbends, rabbets, and stops are all formed from
one piece of metal for each jamb and for each head.

integral garage A garage that is part of the
structure of a building.

integral lean-to In a colonial timber-framed
house in America, a lean-to that was part of the
original house construction, not a later addition
or separate structure. This construction permit-
ted the use of continuous rafters between the
roof ridge and the eaves of the lean-to, thus pro-
viding a long, sloping roof of uniform pitch.

integral lock A type of mortise lock having its
cylinder in the knob.

integral mullion See impost, 2.

integral porch A porch whose floor is set
within the main structure of a house, rather than
being attached to the house, as in a projecting
porch.

integral waterproofing The so-called "water-
proofing" of concrete by the addition of an
admixture during the mixing of the cement.

540

intercolumniation

:^~

Static

water level s screen

Removable
filter screen

pT Slots in
removable
separating

screen ^-^

oil interceptor

integral lock

integral porch

integrated ceiling A suspended ceiling system
in which the acoustical, illumination, and air-
handling components are combined as an inte-
gral part of a grid system.

intelligent building A building that has a
fully-integrated control system in which build-
ing services are monitored and controlled by a
computer-based management system.

intercepting chamber A manhole.

intercepting drain A drain located between
the water source and the protected area.

intercepting sewer A sewer which receives
the dry-weather flow from a number of branch
sewers or outlets (and sometimes a determined
quantity of storm water).

intercepting trap Same as interceptor.

interceptor A device to trap, remove, or sepa-
rate deleterious, hazardous, or undesirable mat-
ter (such as oil, grease, gasoline, sand, and
sediment) from normal waste conveyed through
it, permitting normal sewage or liquid wastes to
discharge into the disposal terminal by gravity.

intercolumniation l.The clear space between
two adjacent columns, usually measured at the
lower parts of the shafts. 2. The system of spacing

(g) l| (g) PYCNOSTYLE

(7) ' ra) SYSTYLE
Q) H Q EUSTYLE

(^ 3 ("") DIASTTLE

Diagram of intercolumniation

Examples of intercolumniation: A areostyle; B coupled
columns; C diastyle; D eustyle

541

intercom

between columns which determines the style: pyc'
nostyle, 1 Vi diameters; systyle, 2 diameters; eustyle,
2 l A diameters; diastyle, 3 diameters; areostyle, 4
diameters.

intercom See intercommunication system.

INTERCOM On drawings, abbr. for "inter-
communication system."

intercommunication system A communi-
cation system within a building or group of
buildings with a microphone for speaking, and a
loudspeaker for listening, at each of two or more
locations.

interconnection Any physical connection or
arrangement of pipes between two otherwise
separate building water-supply systems whereby
water may flow from one system to the other, the
direction of flow depending upon the pressure
differential between the two systems; also called
a cross-connection.

inter»crimp In wire cloth, extra corrugations in
the wires between points of crossing; usually
applied to fine wire cloth having a wide mesh, to
assure proper locking of the wires.

intercupola 1 . The space between two cupolas.
2. The space between two shells of a cupola.

interdentil The space between two dentils.

interdome The space between the inner and
outer shells of a dome.

interduce Same as intertie.

interface The common boundary, often a plane
surface, between two bodies or materials.

interfenestration The space between windows
in a facade consisting chiefly of the windows
with their decorations.

interfilling Same as infilling.

interglyph The space between two grooves or
cuts, as in a triglyph; usually a flat surface below
which the groove itself has been sunk.

intergrown knot, live knot A knot whose
growth rings are intergrown with the surround-
ing wood.

interior casing See inside casing.

interior chimney A chimney that is built
within the walls of a structure; often categorized
according to its location, for example, an end
chimney; compare with exterior chimney.

interior design In a building, the planning,
decoration, and furnishing of the interior.

interior door A door installed in an interior
wall of a building, separating rooms or spaces
within it.

interior finish The exposed interior surfaces of
a building, such as plaster or wood, or applied
materials such as wallpaper, paint, or trim. Inte-
rior finishes may be classified according to an
ASTM test for the surface burning characteris-
tics of building materials, class A being the best
and class E being the poorest in ability to resist
fire propagation.

interior fit-out The installation of ceilings,
floors, furnishings, and partitions of a building,
as well as the installation of all required building
services.

interior glazed Said of glazing that has been
set from within a building.

interior hung scaffold A scaffold suspended
from the ceiling or roof structure.

interior lot A lot bounded by a street on one
side only.

interior plywood A plywood, bonded with
glue, that has limited moisture resistance; not
durable when exposed to frequent or continuous
wetting.

interior stair A stair, within a building, that
serves as an exit required by code.

interior trim, inside finish Trim used on the
interior of a building, esp. around door and win-
dow casings, baseboards, stairs, etc.

interior wall A wall within a building, entirely
surrounded by the exterior walls.

interjoist The space between two joists.

interlace, entrelacs An ornament of bands or
stalks elaborately intertwined, sometimes includ-
ing fantastic images. Also see knot.

an ornament with interlace

542

internal glazing

interlaced arches See interlacing arcade.

interlaced fencing, interwoven fencing,
■woven board Fencing made from weaving
thin, flat boards together.

interlacement band Same as guilloche.

interlacing arcade Arches resting on alter-
nate supports in one row, the arches overlapping
in series where they cross. Also see intersecting
arcade.

interlacing arcade

interlayer The plastic layer between two sheets
of glass in the manufacture of laminated glass.

interlocked Two or more components, mem-
bers, or items of equipment which are arranged
mechanically or electrically to operate or to be
placed in some specific relationship with each
other.

interlocked grain, twisted grain Wood in

which the fibers are angled in different direc-
tions every few annual rings; produces ribbon-
stripe grain when quartersawn.

interlocking joint 1 . A form of joggle in which
a rib or other protrusion on one stone comple-
ments a routed groove or slot on another; pre-
vents relative displacement. 2. A joint formed
between sheet-metal parts by engaging their
edges which have been preformed to provide a
continuous locked splice.

interlocking tile A single-lap tile made so
that an edge of one tile fits under a groove along
an edge in the next tile in the same course.

intermediate course Same as binder course.

intermediate floor beam In floor framing,
any floor beam between the end floor beams.

intermediate joist One of a number of full-
length common joists, running from one wall to
the other, on which floorboards are laid.

intermediate landing A horizontal platform
between flights of stairs separating two floors.

intermediate metal conduit (IMC) See
electrical metallic conduit.

intermediate post A vertical post that is similar
in function to, but smaller than, a principal post.

intermediate rafter See common rafter.

intermediate rail A horizontal member of a
door which is between the top rail and the bot-
tom rail.

intermediate rib 1. A rib in vaulting subordi-
nate to the primary ribs. 2. In a sexpartite vault,
the transverse rib in the middle of the bay, above
the intermediate and smaller piers.

intermediate stiffener Any one of the stiffen-
ers on a beam or girder between the end stiffeners.

intermediate-temperature-setting adhesive
An adhesive that sets in the temperature range
87°to211 F(31 to99°C).

intermediate truss The center truss of a
three-truss span.

intermetium In an ancient Roman circus, a
long barrier running down the arena between
the two metae.

intermittent-flame-exposure test Part of
an ASTM fire test of roof coverings; specified
gas flames are applied to the test specimen for 3
to 15 cycles, according to the classification of
roof covering.

intermittent weld A weld whose continuity is
broken by recurring unwelded spaces.

intermodillion The recess between two modil-
lions.

intermutule The space between two mutules,
as in an architrave.

internal dormer A vertical window in a
sloped roof; unlike the usual dormer window, it
is not covered by a small pitched roof, but pro-
jects down from (and is set below) the slope of
the main roof.

internal drainage The removal of water (for
example, by weep holes) that has penetrated the
exterior layers of a composite wall.

internal glazing Glazing installed in internal
partitions. Also see inside glazing.

543

internal lining

internal lining A lining of the internal sur-
faces of an HVAC duct with an incombustible
acoustical material, such as fiberglass, so as to
attenuate the transmission of airborne sound
along the interior of the duct.

internally fired boiler A boiler whose fur-
nace is wholly or partly surrounded by water.

internal-partition trap In plumbing, a trap, 1
forming a seal by use of an internal partition;
usually considered undesirable because of the
possibility of holes developing in the partition.

internal-quality block A masonry block suit-
able only for concealed work.

internal-quality brick Brick suitable only for
concealed work.

internal stress The stress that exists in a com-
ponent (for example, at a joint) in the absence
of applied external forces.

internal thread Same as inside thread.

internal treatment Water treatment by chem-
icals fed into a boiler rather than into the water
before it enters the boiler.

internal vibration Energetic agitation of
freshly mixed concrete by means of a vibrating
device which is inserted into the concrete at
selected locations.

intern architect One pursuing a program of
training in practice under the guidance of prac-
ticing architects, with the objective of qualifying
for registration as an architect.

International Code Council (ICC) An

organization that is the consolidation of the
BOCA, ICBO, and SBCCI.

International Conference of Building
Officials ( ICBO ) An organization that pro-
duces a widely-used model building code in the
US. Home office: Whittier CA 90601-2298.

International Revival A term occasionally
used to describe a 1970s adaptation of the Inter-
national style that emphasizes the use of pure
geometric forms.

international rubber hardness degree A

measure of hardness, the magnitude of which is
derived from the depth of penetration of a speci-
fied indenter into a test specimen; 0° represents a
material showing no measurable resistance to
indentation, and 100° represents a material
showing no measurable indentation.

International Standards Organization,
International Organization for Stan-
dardization (ISO) A body which promotes
the development of world-wide standards and
which publishes such standards.

International style An architectural style that
is minimalist in concept, devoid of regional char-
acteristics, stresses functionalism, and rejects all
nonessential decorative elements; it emphasizes
the horizontal aspects of a building; developed
during the 1920s and 1930s, in western Europe
principally in the Bauhaus school, and also in
America. Buildings in this style are usually char-
acterized by simple geometric forms, often recti-
linear, making use of reinforced concrete and steel
construction with a nonstructural skin; occasion-
ally, cylindrical surfaces; unadorned, smooth wall
surfaces, typically of glass, steel, or stucco painted
white; a complete absence of ornamentation and
decoration; often, an entire blank wall; often a
cantilevered upper floor or balcony; open interior
spaces; a flat roof without a ledge; eaves that ter-
minate at the plane of the wall; large areas of
floor- to-ceiling glass or curtain walls of glass;
metal window frames set flush with the exterior
walls, often in horizontal bands; casement win-
dows; sliding windows; glass-to-glass joints at the
corners, without framing; plain doors that con-
spicuously lack decor rative detailing. Houses are
commonly asymmetric; in contrast, commercial
buildings in this style are not only symmetric, but
appear as a series of repetitive elements.

International System of Units (SI) A sys-
tem of units based on the following fundamental
quantities: metre, kilogram, second, ampere,
kelvin, candela, and mole.

interpier sheeting Horizontal sheeting (usually
wood) placed horizontally between underpinning
pits; used where continuous underpinning is not
required.

inter pit sheeting The interpier sheeting
which is between concreted underpinning pits.

interrupted acoustical ceiling A discontin-
uous, suspended acoustical ceiling; the top of a
partition extends through the upper surface of
the ceiling. The partition may or may not
extend upward to the overhead structure.

interrupted arch A segmental pediment whose
center has been omitted, often to accommodate
an ornament.

544

inverse-square law

interrupted arch molding A common Nor-
man molding consisting of a series of interrupted
arches.

OOP OO O J> 5 3 O GO Q

interrupted arch molding

interrupted foundation A foundation, 1 that

consists of individual pilings or piers.
interrupted shear wall A shear wall that is

not continuous from the top of the wall to its

foundation.
intersecting arcade Arches resting on alternate

supports in one row, the arches meeting on one

plane at the crossings. Also see interlacing arcade.

1 *$

' 11

f -■:■

~5L

intersecting arcade

intersecting gable See cross gable.

intersecting tracery Tracery formed by the
curving upward, forking, and continuation of the
mullions, springing from alternate mullions or from
every third mullion and intersecting each other.

interstitial condensation Condensation of
water vapor within an element of a building, e.g.,
within a wall.

interstitium The crossing, 1 in a cruciform
church.

intertie In framing, a horizontal member,
between the sill and head, which extends from
one stud to the next in order to stiffen them.

inter- tie Same as nogging piece, 1.

intertriglyph The space between two triglyphs
in a Doric frieze; a metope.

interval tower One of many towers situated
along the length of a curtain wall, 2.

interwoven fencing See interlaced fencing.

intgl Abbr. for "integral."

intonaco The fine finish coat of plaster made
with white marble dust to receive a fresco
painting.

intrados The inner curve or face of an arch or
vault forming the concave underside.

intruder alarm system Same as burglar alarm
system.

intumescence The process of swelling up, as
with the application of heat, such as vermiculite
that is heat-treated for use in thermal insulation.

intumescent Said of a material that swells and
chars when exposed to flame and that forms an
insulating fire-retardant barrier between the
flame and material.

intumescent paint Paint that swells and chars
when exposed to flame, thus making the surface
more fire-retardant.

inverse condemnation A legal doctrine hold-
ing that, in certain circumstances, where private
property is destroyed or substantially diminished
in value by government action, the conduct of
the government is regarded as the taking of the
property and the owner of the property must be
compensated in fair value by the government.

inverse-square law A law which applies to a
light source (or to a sound source) that is in a
space far away from any reflecting surface: the
intensity at a point, as measured on a surface
which is perpendicular to a line drawn between
the point and the source, varies inversely with the
square of the distance between the point and the
source. (For sound waves, this decrease in inten-
sity is equivalent to a drop in sound-pressure level
of 6 dB for each doubling of distance from the
source.)

inverse-square law

545

invert

invert In plumbing, the lowest point or the low-
est inside surface of a channel, conduit, drain,
pipe, or sewer pipe.

inverted arch An arch with its intrados below
the springing line; esp. used to distribute con-
centrated loads in foundations.

inverted arch

inverted joint A fitting, 1 which is turned
upside down, reversed in position, or turned in
an opposite direction.

inverted roof A roof membrane whose ther-
mal insulation is above, rather than below, the
membrane.

inverting ballast A lamp ballast, 1 designed to
operate on direct current.

invisible hinge A hinge so constructed that
no parts are exposed when the door is closed.

invitation to bid That portion of the bidding
documents which solicits bids for a construction
project. Also called an invitation to tender.

invited bidders The bidders selected by the
architect and the owner as the only ones from
whom bids will be received.

involute 1 . A curve traced by a point at the end
of a string as the string is unwound from a sta-
tionary cylinder. 2. Curved spirally.

inwrought Closely combined or profusely
embellished.

Ionic 1. Pertaining to, or characteristic of,
Ionia, the eastern part of the Greek world. 2.
Same as Ionic order.

Ionic capital The topmost member of a col-
umn of the Ionic order; the twin volutes in the
Greek Ionic order are larger and more conspicu-
ous than the corresponding volutes in the
Roman Ionic order.

Ionic order One of the five orders in Classical
architecture, originated by the Ionian Greeks.
Usually characterized by columns usually having
24 flutes separated by narrow fillets; an entabla-
ture, a frieze without triglyphs; dentils in the
cornice; elegant detailing; less elaborate than
the Corinthian order and less heavy in appear-
ance than the Doric order. Pilasters in the Ionic
order often have fluted shafts with a capital con-
sisting of a band of anthemions, with egg-and-
dart moldings above.

Ionic order: above, capital; below, base

ionization-type detector A type of fire detec-
tor that uses a radioactive source to develop a
current across an air gap within the detector;
when products of combustion enter the detector,
they alter the flow of current and activate an
alarm; particularly useful where early-warning
detection is essential either because of special
safety requirements or because protection is
required for property of high value.

IPS l.Abbr. for "iron-pipe size"; a nominal
dimension, inside diameter. 2. Abbr. for "Inter-
national Pipe Standard." 3. Abbr. for "inside
pipe size."

IR Abbr. for "inside radius."

546

Islamic architecture

iridescent glass A translucent glass having an
iridescence similar to that of a soap bubble; see
opalescent glass.

Irish moss An Atlantic Coast seaweed; used to
make size for paint.

iron A ductile metallic element from which pig
iron and steel are made; used in its relatively
crude form for making tools, castings, and so on.
Also see bar iron, cast iron, malleable iron, orna-
mental iron, wrought iron.

iron back A cast-iron fireback.

iron blue See Prussian blue.

iron cement A cement composed of cast-iron
borings or filings, sal ammoniac, and additives;
used for mending or joining cast-iron parts.

iron core Of stairs, a steel bar enclosed by a
wooden handrail.

iron framing A system of structural ironwork
for buildings, first developed at the end of the
18th century. The Crystal Palace, constructed in
New York City in 1853, provided a dramatic
example of its application in America. Also see
cast iron and cast-iron front.

ironmongery (Brit.) A term for hardware, par-
ticularly that used for doors and windows.

iron oxide A principal ingredient in a family of
inorganic pigments, ranging from yellow through
red and from purple to black; used extensively in
paints.

iron pipe size The nominal inside dimension
of a pipe.

iron titanate See ilmenite.

ironwork Objects or parts of objects made of
cast iron or wrought iron; initially utilitarian,
later often elaborate and ornamental; also see
cast-iron lacework.

irradiance The density of the luminous flux
which is incident on a surface.

irregular pitch A roof whose slope is not con-
stant.

irrigation pipe Any type of pipe through which
water is distributed for irrigation.

irrigation system See lawn sprinkler system.

Isabelline architecture See Plateresque archi-
tecture.

Isabellino style A style of Spanish architecture
popular during the reign of Isabella and Ferdinand
(1474-1516).

I»section A rolled or extruded structural metal
beam that resembles the capital letter I in verti-
cal cross-section.

Islamic architecture, Muslim architec-
ture The architecture of the peoples of
Islamic faith, also called Mohammedan, which
from the 7 th century onward expanded
throughout the Mediterranean world and as far
as India and China, and beyond, producing
a variety of great regional works and local
decorative styles. It is characterized by domes,
horseshoe and round arches, tunnel vaults and
richly decorated ornamentation which is
geometric because of the ban on human and
animal representation. Also see Muslim archi-
tecture. (See illustration p. 548.)

547

island

Islamic horseshoe arch

island In the design of a parking lot (car park) , a
raised area having a curb, so located to separate
traffic lanes and/or to guide traffic.

island-base kitchen cabinet A free-standing
kitchen cabinet placed below a counter or work
surface; the ends of the cabinet are exposed.

ISO Abbr. for International Standards Organi-
zation.

isocephalic In bas-relief, having the heads
nearly on a horizontal line; esp. said of the heads
of human figures in a frieze or band.

isodomum In ancient Roman masonry and
Greek, an extremely regular masonry pattern in
which stones of uniform length and uniform
height are set so that each vertical joint is cen-
tered over the block beneath. Horizontal joints
are continuous, and the vertical joints form dis-
continuous straight lines; opus isodomum.

isocephalic: from the frieze of the Parthenon

isodomum

isofootcandle line See isolux line.

isolated Said of a space not readily accessible to
persons unless special means for access are used.

isolating strip Same as expansion strip.

isolating switch A switch for isolating an elec-
trical circuit from its source of power; it is intended
to be operated only after the circuit has been
opened by some other means.

isolation joint A joint, such as an expansion
joint, between two adjacent structures which are
not in physical contact.

isolation strip Same as expansion strip.

isolation transformer In an electrical system,
a transformer that prevents one section of the
system from undesirably influencing another
section.

isolator See vibration isolator.

isolux diagram See isolux line.

isolux line A line through all points on a sur-
face where the illumination is the same; called
an isofootcandle line if the illumination is
expressed in footcandles. A series of such lines
for various illumination values is called an
"isolux diagram."

548

isometric drawing A form of three-dimen-
sional projection in which all of the principal
planes are drawn parallel to corresponding
established axes and at true dimensions; hori-
zontals usually are drawn at 30° from the normal
horizontal axes; verticals remain parallel to the
normal vertical axis.

t dimensions

^^r-

true>

».

,.-■

^"*

sometrtc^

jrawi

Italian order

very low-pitched roof; mullions divide both the
upper and lower window sashes vertically into
two panes. Commercial Italianate style buildings:
a raised pediment above the roofline at the center
of the facade, often with the name of the building
and/or the date of its completion, and a cast-iron
facade. Palazzi: See Italian Renaissance Revival.

Italianate style buildings are commonly char-
acterized by a two-storied structure with exterior
wall surfaces of smooth ashlar masonry, and
rough-cast brick, stucco, or wood clapboard sid-
ing; classical columns, and pilasters; balustraded
balconies; a belt course encircling the building;
wide, projecting cornices with decorative brack-
ets for support; corner quoins; a square tower; a
porch; a gabled roof and/or hipped roof; a cupola
or belvedere, chimney shafts with ornate caps;
narrow double-hung window sashes commonly
having arched (rather than rectangular) upper
sashes; windows often topped with a segmental
arch, with a hooded crown, or with a crown sup-
ported by decorative brackets; a pair of decora-
tively paneled double doors at the main
entrance, the upper parts of which are glazed;
often, a round-topped door or a door set in a
round arch. The latter phase of Italianate style,
sometimes referred to as High Victorian Ital-
ianate, is usually more highly decorated than its
earlier counterpart. Also see Tuscan Villa style.

isometric drawing

isothermal Said of a process which takes place
at constant temperature.

isotropic Said of a building material that has
the same physical properties in all directions.

1ST Abbr. for inside trim.

IstructE A designation for the Institution of
Structural Engineers in London.

ISWG Abbr. for "Imperial standard wire gauge."

Italianate style An eclectic style of Italian-
influenced residential and commercial architec-
ture; fashionable in England and America from
the 1840s to around 1890. Italianate style resi-
dential buildings may be classified as: Villas:
Domestic architecture intended to resemble pros-
perous farmhouses or country manor houses of
northern Italy; usually two stories high, with an
attic story; Town houses: Urban row houses, com-
monly three or four stories in height with a flat or

Italianate style villa

Italian molding A wide, heavy bolection

molding, often used to surround a fireplace.
Italian order Same as Composite order.

549

Italian Renaissance Revival

Italian Renaissance Revival An architec-
tural style emulating the Renaissance palazzi of
Northern Italy; most popular from 1800s to
about 1930. Buildings in this style are usually
characterized by facades that are commonly sym-
metrical and essentially flat; rectangular or
square in plan; usually two or three stories high;
masonry or stucco walls; a different architectural
treatment on different stories; an elaborate belt
course between stories; a massive cornice that
rests directly on the architrave (the frieze being
omitted); pilasters, rusticated quoins, dentils,
and decorative detailing; a recessed entry porch
flanked with classical columns or pilasters;
prominent arcading on the ground floor of public
buildings and a recessed arcaded gallery on the
floors above; commonly, a low- to moderate-
pitched, ceramic-tiled hipped roof; widely over-
hanging eaves with decorative brackets below;
occasionally, a flat roof with a balustrade or

Italian Renaissance Revival

roofline parapet above an elaborate cornice;
commonly, a different type of window on each
story; on the ground floor, elaborate, tall, narrow
windows placed in a regular pattern, set symmet-
rically on both sides of the main entrance; the
second-story window heads often pedimented
and supported by ancons in elaborate buildings;
windows on the uppermost story are usually the
smallest and simplest, being square in shape;
arches frequently above exterior doors; a hooded
entryway; an entablature, supported by pilasters,
over the entrance. Sometimes called Italian
Renaissance style or Second Renaissance
Revival, this style is occasionally subdivided into
the North Italian or Venetian mode and the
Romano-Tuscan or Florentine mode.

Italian Renaissance style Same as Italian
Renaissance Revival.

Italian roof See hipped roof.

Italian tile Same as mission tile.

Italian tiling Same as pan-and-roll roofing tile.

Italian Villa style A term often used as a syn-
onym for Italianate style.

itinera versurarum The side entrances from
the wings to the stage of an ancient Roman
theater.

ivory black See animal black.

iwan A large vaulted hall having one side open
to a court; prevalent in Parthian, Sassanian, and
Muslim architecture.

izba A Russian log cabin, log house, or hut.

Izod impact test A type of impact test in which

a single impact is delivered by a falling pendulum.

550

J Symbol for joule.

J&P Abbr. for "joist and planks."

jacal 1. A rectangular structure, either partially
enclosed or open on all four sides, used as a tem-
porary storage place, such as for grain; usually a
flat roof supported by two to four posts on each
side of the structure (depending on its size) and
often covered with a layer of adobe mud or straw.
2. In the American Southwest, a crude house
having walls built of closely spaced upright
sticks, or poles driven into the ground, and small
branches interwoven between them; then cov-
ered with mud or an adobe clay; usually plastered
to provide additional weather protection; a flat
roof is supported by horizontal logs and then
covered with thatching, often with a layer of
adobe atop the thatching. 3. Same as wigwam.

jack l.A portable machine, variously con-
structed for exerting great force for moving a
heavy body through a short distance. Also see
hydraulic jack; jackscrew. 2. An electrical
receptacle into which a plug, 7 is inserted to
make electrical contact between communica-
tion circuits.

Plug
\

Well Jack

jac

k,2

jack arch Same as flat arch.

jack beam A beam that supports another beam
and eliminates the need for a supporting column.

jack boom A boom which supports sheaves
that carry lines to a working boom.

jacked pile A pile (usually sections of pipe
spliced together) which is forced into the ground
to a bearing stratum, jacking it against a building or
structure above; used primarily for underpinning.

jacket l.A metal or cloth covering over the
heat insulation which is applied to exposed
heating pipes and ducts. 2. An outer casing
around a pipe or vessel, the space between being
filled with a fluid for cooling, heating, or main-
taining a fixed temperature.

jackhammer l.An airhammer. 2. A hand-
operated, pneumatic, rock drill.

jacking The imposition of a static driving force
on a pile by the use of jacks; a technique widely
used for installing piles in the underpinning of
structures.

jacking device l.A device used to raise a ver-
tical slipform. 2. A device used to stress the ten-
dons in prestressed concrete.

jacking dice In foundation work, blocks used
as temporary fillers during jacking operations.

jacking force The force exerted temporarily
by the device which introduces tension in ten-
dons in prestressed concrete.

551

jacking plate

jacking plate A steel plate, atop a pile during

jacking operations, which is used to transmit the

load of the jack to the pile.
jacking stress The maximum stress occurring

during the stressing of a tendon in prestressed

concrete.
jack lagging The rough lagging, 2 in centering

an arch or vault.
jack pile Same as jacked pile.
jack plane A carpenter's plane, of medium size;

used for coarse work.
jack post A post comprising two telescoping

sections, so that it is adjustable in height; used

to support a floor beam.
jack rafter Any rafter that is shorter than the

usual length of the rafters used in the same

building; esp. occurs in hip roofs.

■-HIP RAFTER

JACK RAFTER

jack rafter

jack rib Any rib in a framed arch or dome
shorter than the others.

jackscrew A jack in which a screw is used for
lifting; carries a plate which bears on the load.

jack shore A telescoping, or otherwise adjus-
table, single-post metal shore.

jack timber A timber in a framework which,
being intercepted by some other piece, is shorter
than the rest.

jack truss A roof truss which is smaller in size
than the others, usually because of location, as
in a hip roof.

Jacobean architecture An imprecise term,
applied to an English architectural style of the
early 17 th century that adapted the Elizabethan
style to continental Renaissance influences;
applied to buildings erected during the reign of
James I (1603-1625) and thereafter. Large houses

Jacobean architecture

a manor house

were usually two to three stories high and might
have elaborate multicurved Flemish gables, Tudor
arches, and decorative chimneys, and casement
windows (separated by stone or cement mullions)
that had small, diamond-shaped panes of glass
held in place by grooved strips of lead.

Jacobethan style, Jacobethan Revival A
mode of Tudor Revival architecture, of limited
popularity from the 1800s to about 1920, that
was a blend of Jacobean and Elizabethan archi-
tecture; hence, the compound term. Such build-
ings are often characterized by front-facing
gables that rise above the roofline; elaborate
brickwork or stonework; quoins at the corners of
the building; occasionally, turrets or towers;
stone straight-line gables or multicurved gables,
tall decorative chimneys; rectangular window
frames, usually containing small, leaded panes of
glass set in casement sashes.

jagging Notching or indenting, as on beams.

jail l.A prison. 2. A building or place for the
legal detention of persons.

552

japan

jal-awning window A window having a
number of top-hinged out-swinging pivoted
sashes (ventilators, 2) one above the other,
which are operated by one or more controls,
with individually operated locking mechanisms.

jalousie A shutter or blind with fixed or
adjustable slats which exclude rain and provide
ventilation, shade, and visual privacy.

jalousie 'window A window consisting of a
series of overlapping horizontal glass louvers
which pivot simultaneously in a common frame
and are actuated by one or more operating
devices so that the bottom edge of each louver
swings toward the exterior and the top edge
swings toward the interior during opening.

jamb One of the vertical members at each side
of an opening such as a doorframe, window
frame, or fireplace.

jamb anchor A metal device inserted in the
back of the jamb of a doorframe or window
frame to anchor the frame to the wall.

jamb block, sash block A concrete masonry
unit which has an end slot (rabbet) for use at an
opening to receive a jamb.

jamb block

door jambs

vind

ow jamb

jamb depth The overall depth of a door-frame,
measured from one face to the other.

jamb entension The section of a metal door
jamb which extends below the level of the finish
floor for attachment to the rough floor.

jamb horn The part of the jamb of a window
frame which extends beyond the sill or head
jamb.

jamb lining 1 . A strip of wood which is applied
to the inside edge of a window jamb to increase
its width. 2. Same as door case.

jamb post An upright timber at the side of an
opening; a wood jamb.

jamb shaft A small shaft having a capital and a
base, placed against or forming part of the jamb
of a door or window; occurs mostly in medieval
architecture. (See illustration p . 552.)

jambstone A stone which forms a jamb of a
door.

jamb stove An 18th cent, cast-iron stove at
the back wall of a fireplace; projects into and
heats the room adjoining the back of the fire-
place.

jam nut Same as locknut.

janua In ancient Roman architecture, a front
door which opens on the street.

Janus Same as bifrons.

japan A short-oil varnish, usually dark in color,
which produces a hard glossy surface.

553

Japanese architecture

jamb shaft

Japanese architecture Architecture of timber
construction exclusively, from the 5th cent. A.D.
under the strong influence of China. Simple pavil-
ion-like structures consist of a wooden framework
of uprights and tie beams supported by a platform,
with nonbearing plaster or wood panel walls, slid-
ing partitions, and doors and windows of light-
weight material — often paper. The tiled, hipped
roofs are widely projecting and upward-turning,
on elaborate bracket systems. Stone is used only
for pillar bases, platforms, and fortification walls.
Great emphasis is put on the integration of build-
ings with their surroundings, with verandas pro-
viding the transition. Proportions of floor
dimensions, height, and length of walls follow
fixed standards. Modern Japanese architecture,
though under strong Western influence, has

developed a reinforced concrete style of its own,
steeped in its tradition of timber construction.

Japanese ash, tamo A light, yellowish wood
having a grain similar to oak; esp. used for veneer.

Japanese lacquer See Chinese lacquer.

Japanese tung oil See tung oil.

jardin anglais Literally, an English garden, par-
ticularly popular in the 18th century.

jaspe Mottled and marbled to resemble varie-
gated stone, and to mask signs of use; e.g., jaspe
linoleum.

jawab A false building or structure which is
constructed for aesthetic reasons, to achieve a
desired balance or proportions.

jaw crusher A machine for crushing rock
between two inclined jaws.

JB Abbr. for junction box.

JCT On drawings, abbr. for "junction."

jealous glass Any nontransparent glass, for
example, ground glass.

jedding ax A stonemason's tool; a kevel, 1.

Jeffersonian Classicism See Classical Revival
architecture.

jemmy Same as jimmy.

jenny A machine which shoots out a jet of
steam; used for cleaning surfaces.

jerkinhead, clipped gable, hipped gable,
shreadhead The end of a roof when it is
formed into a shape intermediate between a
gable and a hip; the gable rises about halfway to
the ridge, resulting in a truncated shape, the roof
being inclined backward from this level.

jerkinhead

jerrybuilt Built in a flimsy manner.
Jerusalem cross A Greek cross with a smaller

Greek cross inscribed in each of the four spaces

between the arms.

554

joinery

Jesse window A painted window containing a
decorative genealogical tree representing the
genealogy of Christ.

jesting beam A beam introduced for the sake
of appearance and not for use.

jettied house A house having an overhanging
second story. See also garrison house.

jetted pile A pile which has been sunk by jet-
ting.

jetting 1. The sinking of piles or well points by

the use of a water jet, e.g., through a hole in a
cast concrete pole or by inserting a pile in a hole
produced by jetting; esp. used where pile driving
may damage neighboring buildings. 2. The com-
pacting of backfill around a pipe by introducing
water under pressure in the trench in which the
pipe is laid.
jetty A projecting part of a building, as a bay
window or the upper story of a timber house.

jib 1. Of a crane or derrick, see boom, 2. 2. Same
as gib or jib door.

jib boom A piece which extends the upper end
of a boom, 2.

jib crane A crane having a swinging boom.

jib door, gib door A door which is flush with,
and treated in the same manner as, the sur-
rounding wall so as to be concealed; has no visi-
ble hardware on the room side.

jib window Same as jib door.

jig A device for guiding or holding a part or parts
in correct mechanical alignment, either in the
process of fabrication or in the final assembly of
the parts.

jigger saw Same as jigsaw.

jigsaw An electrically powered saw having a
narrow blade which moves with a reciprocating
motion, in a vertical direction, through the sur-
face of a table on which work is placed; esp. used
for cutting curves and ornamental patterns.

jimmer See gemel.

jimmy, jemmy A short crowbar.

jinnie wheel Same as gin block.

jitterbug A tamper, usually pneumatic, for
concrete.

job 1. Same as project. 2. Same as work, 1.
job captain A member of the architect's staff
normally responsible, on a given project, for the

preparation of drawings and their coordination
with other documents.

job site The site, 1 of a construction project.

job superintendent See superintendent.

jog Any irregularity in a line or surface.

joggle 1. A notch or projection in one piece of
material which is fitted to a projection or notch in
a second piece to prevent one piece from slipping
on the other. 2. A stub tenon on the end of a tim-
ber which prevents the timber from moving later-
ally; also called a joggle joint, 2. 3. An enlarged
area on a post to support the foot of a strut.

joggle beam A built-up beam, the parts of
which are fixed in place by joggles.

joggle joint l.A joint between two blocks of
material (such as masonry) which fit one into
the other by a joggle, 1. 2. Same as joggle, 2.

joggle joints

joggled lintel A series of masonry joggle joints,

united so as to form a lintel.

joggle piece A joggle post, 2.

joggle post l.A post made of two or more
pieces of timber joggled together. 2. A king post
having shoulders or notches at its lower end to
support the feet of struts.

joggle tenon Same as stub tenon.

joggle truss A roof truss with a single post
placed centrally and fitted to the chord by a sub-
tenon or the like, the chord being on top, and
the post hanging downward and having its lower
end connected with the ends of the chord by
oblique braces.

joggle 'work In masonry, construction in which
stones are keyed together by joggles, 1.

joiner's chisel Same as paring chisel.

joiner's finish See carpenter's finish.

joiner's gauge A marking gauge.

joinery The craft of woodworking by joining
pieces of wood, esp. of the finish and trim work-
ings of the interior of a structure, such as doors,
paneling, sashes, etc., as distinguished from car-
pentry, which suggests framing and rough work.

555

joining

joining The junction of two separate plaster
applications of the same coat, usually within a
single surface plane.

joint 1. The space between adjacent surfaces (as
between masonry units), or the place where two
members or components are held together by
nails, fasteners, cement, mortar, etc. 2. In steel
construction, the area where two or more steel
surfaces are attached; often characterized by the
type of weld or fastener employed. Also see
masonry joint and wood joint.

joint backing Same as backing strip.

joint bolt See handrail bolt.

joint compound In gypsum board construc-
tion, a compound used for taping and/or finish-
ing joints.

joint efficiency In welding, the ratio of the
strength of a joint to the strength of the base
metal; expressed in percent.

jointer 1. A metal tool used to cut a joint partly
through fresh concrete. 2. In masonry, a tool for
filling the cracks between courses of bricks or
stones. 3. In masonry, a bent strip of iron
inserted into a wall to strengthen a joint.
4. In carpentry, a long plane, esp. used to square
the edges of boards or veneer so that they will
make a close joint with other pieces.

jointer plane Same as jointer, 4.

joint factor Same as joint efficiency.

joint fastener See corrugated fastener.

joint filler l.Any putty-like material used to
fill joints, as in plasterboard construction. 2. A
strip of extruded resilient material used for filling
a joint.

jointing l.In masonry, the finishing of joints
between courses of bricks or stones before the
mortar has hardened. 2. The machining of a true
and flat surface on one face or edge of a wood
member. 3. The first operation in sharpening a
cutting tool, whereby the tips of all teeth or
knives are ground or filed to the intended cut-
ting circle.

jointing compound Any material used to seal
a plumbing joint.

jointing rule A long straightedge used by
masons in drawing lines and in pointing.

jointing tool A steel tool used in forming
brickwork joints.

jointless flooring Any type of flooring (e.g.,
terrazzo) that can be laid without construction
joints.

joint mold, section mold A shaped tem-
plate, usually of plywood or zinc; used for casting
a plaster member.

joint movement The difference in width of a
joint between its fully open and fully closed
positions.

joint reinforcement Any type of steel rein-
forcement, such as reinforcing bars or steel wire,
which is placed in or on mortar bed joints.

joint reinforcement tape Any strip of fabric,
woven fiberglass, metal, mesh, paper, or other
material, used with a cementitious material to rein-
force the joint between adjacent gypsum boards.

joint residue An accumulation of foreign mat-
ter, old sealant material, and protrusions that
must be removed from the walls of a joint prior
to sealing.

joint rod, joint rule A piece of metal, usually
2 to 24 in. (approx. 5 to 60 cm) long and 4 in.
(10 cm) wide with a 45° angle cut at one end,
used to form and shape mitered plaster joints in
cornice work.

joint runner In plumbing, an incombustible
material (such as asbestos) used to hold molten
lead that is poured in the bell of a joint, such as
a bell-and-spigot joint.

AUSSTOS *unNEK

joint runner

joint sealant 1. An impervious sealant used to
fill joints or cracks in concrete or mortar. 2. See
preformed sealant. 3. See jointing compound.

556

judgment lien

joint shingle A wood roofing shingle that is
attached by nailing edge to edge rather than
overlapping.

joint tape A tape used to cover joints formed by
adjacent sheets of wallboard.

joint tenancy Ownership of property by two or
more persons in which, upon the death of one,
his interest devolves upon the other or others
until a sole owner survives.

joint venture A collaborative undertaking by
two or more persons or organizations for a spe-
cific project (or projects) having many of the
legal characteristics of a partnership.

joist One of a series of parallel beams of timber,
reinforced concrete, or steel used to support
floor and ceiling loads, and supported in turn by
larger beams, girders, or bearing walls; the widest
dimension is vertically oriented. Also see bind-
ing joist, boarding joist, bridging joist, ceiling
joist, common joist, floor joist, principal joist,
sleeper joist.

RAFTER

JOIST

joist

FLOOH SURFACE

JOISTS

■t:cel. wuoci, wood trust)

joists in a flooring system

joist anchor A beam anchor.

joist bridging Same as cross bridging.

joist hanger A metal angle or strap used to fix
a joist to a beam or girder.

joist hangers

joist trimmer Same as trimming joist.

joule A unit of energy or work; equals the
work done by a force of 1 newton which acts
over a distance of 1 metre in the direction of
the force.

journeyman A person who has successfully
served a formal apprenticeship in a building
trade or craft and who is thereby qualified to
work at that trade in another's employ. A jour-
neyman's license (earned through a combina-
tion of education, supervised experience, and
examination) is required in many locales for
those employed at an intermediate level in cer-
tain trades, such as plumbing, mechanical work,
and electrical work.

jowl The enlarged head or foot of a timber, usu-
ally a vertical post; often used to facilitate the
joining of other timbers.

JR On drawings, abbr. for "junior."

JT On drawings, abbr. for "joint."

jube A screen separating the chancel from the
nave or aisles, or both. (See illustration p . 558.)

judas, judas-hole, judas window A small
trap or hole in a door for peering or watching, as
in a prison door.

judgment lien A charge against property of a
judgment debtor (one against whom a judgment
has been rendered by a court and who has not
paid it) to secure payment of the judgment; may
arise automatically in some states by operation

557

Jugendstil

"l m m

jube

of law, and in other states may require certain
procedural steps on the part of the judgment
creditor; acts as an encumbrance on the property
until discharged, usually through satisfaction of
the judgment.

Jugendstil "Youth style"; the German version
of Art Nouveau.

Juliet A medieval stronghold that is circular in
plan; a keep.

jumbo A traveling support for concrete forms.

jumbo brick A brick larger in size than stan-
dard.

jump A step in a masonry foundation.

jump»cut A tree-pruning technique for remov-
ing limbs without stripping bark from the trunk
of the tree.

jumper 1 . A short length of electric cable fitted
with connectors at both ends, connected across
a device in an electric circuit so that the current
bypasses the device. 2. A steel bar which is
moved up and down manually in a borehole in
the ground; used as a drilling or boring tool. 3. In
a stone wall, a stone that is two or more courses,
1 high.

jumper tube A pipe or hose which is used to
bypass the usual flow of a liquid or gas.

jump joint Same as a butt joint or flush joint.

jumpover See return offset.

junction box In electric wiring, a box which
protects splices in conductors or joints in runs of
raceways or cables; has a removable cover to pro-
vide easy access.

Junction
Box

Cable

junction box

junior beam One of the standardized cate-
gories of hot-rolled steel, shaped I-beams.

junior channel A lightweight structural chan-
nel.

junior college A post-high school institution
which offers a 2-year program of study of a ter-
minal nature or in preparation for continued
college studies.

junior mortgage One in which the lender's
claim against the owner is subordinate to that of
a first mortgage holder or another claim which
has priority.

jurisdiction A territory such as a state,
province, county, shire, or municipality, that
enforces building codes, construction standards,
laws, and/or regulations within which its author-
ity is exercised.

jute A plant fiber; forms a cheap, strong, durable
yarn; used in the manufacture of canvas and hes-
sian and for the backing of carpet to add
strength and stiffness.

jutty A jetty.

jut window Any window that projects from
the line of the building, as a bow window or bay
window.

558

k 1. Prefix for "kilo," indicating multiplication
by 1000. 2. Symbol for "coefficient of thermal
conductivity."

K 1. Abbr. for key. 2. Abbr. for kip. 3. Abbr. for
kitchen. 4. Symbol for "Kelvin."

Kaaba A cube-shaped, flat-roofed building in
the center of the Great Mosque at Mecca; the
most sacred shrine of the Muslims.

Kabah Same as Kaaba.

kal'a, qala'a An Arabic fortress or stronghold
built on a hill.

kalamein door A door of composite construc-
tion, usually having a wood core and clad with
galvanized sheet metal, sometimes with panels
of sheetrock or asbestos.

kalamein fire door See metal-clad fire door.

kalsomine Same as calcimine.

kaolin A mineral, usually white, composed
principally of hydrous aluminum silicate, of low
iron content; used in the manufacture of white
cement.

kaolinite One of the clay materials consisting
of a hydrous aluminum silicate.

kasr, qasr An Arabic palace, castle, or mansion.

katabasis In the Greek Orthodox church, a
place under the altar for relics.

katholikon 1. The central nave of a church.
2. The church of a monastery.

KD 1 . Abbr. for kiln-dried. 2 . Abbr. for knocked
down.

KDF Abbr. for "kalamein door and frame."

keblah See kiblah.

keel An appendage of a molding, usually a fillet,
on the furthest projection of a molding.

keel arch Same as ogee arch.

keel molding A brace molding in which
the ogee curves meet sharply at a point or fil-
let more or less resembling the shape of a
ship's keel.

Keene's cement, flooring cement, gyp-
sum cement, hard-burnt plaster, tiling

keel molding: a

plaster A hard, white, high-strength, quick-
setting finishing plaster; takes a high polish;
made by burning gypsum at a high temperature,
grinding to a fine powder, and then adding alum
(to accelerate the set).
keep, donjon The stronghold of a medieval
castle, usually in the form of a massive tower,
and a place of residence, esp. in times of siege.

keep

keeper Same as strike plate.

keeping room A room at the back of a colo-
nial New England house, which served as a com-
bination kitchen, living room, and workroom.

559

Kelly ball test

Kelly ball test, ball test A test which uses a
device consisting of a metal plunger (having a
hemispherical bottom) which is guided by side
stirrups; indicates the consistency of fresh con-
crete by the depth of penetration when the
plunger drops.

kelvin (K) The International Standard unit
of temperature. Absolute zero equals 0°K =
-273.16°C = 459.69°F. A temperature increase
of 1°K is numerically equal to an increase of 1°C.

Kentish rag See ragstone.

Kentish tracery Circumscribed tracery motif,
with foils separated by barbs or with forked
cusps.

keratin A proteinaceous material used as a
retarder for plaster.

kerb British variant of curb.

kerbplate (Brit.) See curb plate.

kerbstone (Brit.) Same as curbstone.

kerf l.In a suspended acoustical ceiling, a
groove cut into the edges of an acoustical tile to
receive splines or supporting members of the
ceiling suspension system. 2. A slot or cut made
in a material such as wood or metal.

kerfed beam A piece of wood having a series
of parallel saw cuts part-way through its back to
permit it to bend more easily.

kerfing Making a series of parallel saw cuts
part-way through the thickness of a piece of
wood to enable the piece to bend toward the
kerfed side.

kerkis In an ancient Greek theater, one of the
wedge-shaped sections of seating of the theater,
divided by radiating staircases.

kettle crane Same as fireplace crane.

kevel, cavel, cavil l.A stone mason's axe
with a flat face for knocking off projecting angu-
lar points, and a pointed peen for reducing a sur-
face to the desired form; also called a jedding
axe. 2. A heavy timber, as a timber bolted
between two stanchions.

kevil Same as kevel.

key 1 . A wedge which passes through a hole in
a projecting tenon to secure its hold. 2. A
piece of metal or wood which is inserted in a
joint to prevent movement between adjacent
surfaces. 3. A piece inserted in the back of a

STEEL DOWEL PIN

STEELTAPERPIN

SQUARE KEY

WOODRUFF KEY

key, 2

board to prevent warping. 4. The last board in
a series of floorboards, tapering in shape, and
serving to hold the others in place when
driven home. 5. The property of a material
that facilitates the bonding of another material
to it. 6. The roughening on the underside of
veneer or similar material to assist it in holding
glue. 7. The roughened surface on the back of
tile or the like to assist it in holding mortar. 8.
In plastering or similar work, that part of the
plastic material that is forced between and
enters the holes in (or clings to the roughened
surface of) the backing lath. 9. A keystone.
10. A groove cut in a surface into which fits a
corresponding projection from a member
above, as a keyed footing. 11. A detachable
metal instrument which operates a lock; it is
inserted into the lock and moves a bolt, latch,
or catch.

key banding, key pattern Same as Greek
key.

key block A keystone.

key bolt Same as cotter pin.

key brick A brick which is tapered toward one
end; used in brick arches.

key console A console, 1 which acts as the
keystone of an arch.

560

key course 1 . A course of keystones in an arch;
used in a deep archway where a single keystone
will not suffice. 2. A course of keystones used in
the crown of a barrel vault.

key drop A keyhole cover, usually attached to
the escutcheon by a pivot.

keyed Said of a concrete form, or the like,
which is fixed in position in a recess or notch.

keyed-alike cylinders Lock cylinders which
are designed to be operated on by the same key,
as opposed to master-keyed cylinders, which
may be opened by the same master key but are
keyed differently.

keyed beam A compound beam having mat-
ing grooves between adjacent layers to resist
horizontal shearing stresses at the interfaces.

keystone

key interlock A mechanism that permits
operation, insertion, or removal of a key to a
piece of equipment only if certain conditions
have been met or prescribed operations have
been completed; may be required to meet speci-
fied safety conditions and to prevent improper
(or unauthorized) operation of the equipment.

key joint pointing, keyed pointing Pointing
in which the soft mortar is pressed and worked
into shape by means of a tool having a convex
edge.

key joint pointing

-ESr-

IjAo.

-ir

keyed beam

keyed brick A brick having a recess in one
face (usually of the dovetail type); used to pro-
vide a mechanical key for plasterwork or ren-
dering.

keyed construction joint Same as joggle
joint.

keyed-differently cylinders Lock cylinders
requiring specific individually designed keys for
their operation.

keyed-in frame A door frame erected with
wall materials forced behind the frame back-
band; the wall thickness is equal to or greater
than the opening between the backhands, but is
not wider than the jamb depth.

keyed joint Same as concave joint.

keyed pointing See key joint pointing.

keyed tenon Same as tusk tenon.

key escutcheon Same as key plate.

keyhole saw A compass saw having an espe-
cially narrow blade and fine teeth.

keying in The bonding of a new brick wall to
an existing one.

keypad lock A door lock that opens when the
correct set of digits has been "punched in."

key pattern See labyrinth fret.

key pile The last pile driven into a bay of sheet-
piling; usually slightly tapered.

key plan A small-scale plan of a building or
building group which indicates the placement of
the principal elements of the scheme.

key plate A small plate or escutcheon having
only a keyhole.

key schedule A table that lists the key num-
bers for all doors on a construction job.

keystone, key block 1. The central voussoir
of an arch, which is often embellished; until the
keystone is in place, no true arch action takes

'(fflUffnmiiniiiiniinniif.

llWIIIlll'I'lll'Fn'Mlllli'lM'FIMIIHPIPFfll'.

•■kiiliHiTii*-

keystone, 1: K

561

keystone arch

place. 2. An element resembling a keystone in
function or in shape.

keystone arch Any arch having a keystone at
its center, but commonly a flat arch or a round-
topped arch.

key switch In an electric circuit, an on-off
switch which can be actuated only by the inser-
tion of a key, 1 1 .

key valve A valve which can be operated only
by the insertion of a key, 1 1 .

keyway 1 . The aperture in a lock cylinder
which receives the key and closely engages
with it throughout its length. 2. A slot used to
interlock slabs of masonry walls built at differ-
ent times.

k factor See thermal conductivity.

kg Abbr. for "kilogram."

khan Same as caravansary.

khaya Closely resembles but is not a true
mahogany; lighter, usually softer, and more
strongly figured than mahogany; esp. used for pan-
eling and veneer.

khory In early Russian architecture, a gallery.

kiblah, keblah, qibla In Islam, the required
orientation of the prayer niche, toward Mecca.

kick In a brick, a shallow indent or frog.

kickboard Same as toeboard.

kicker l.Same as starter frame. 2. A piece of
wood which is attached to a formwork member
to take the thrust of another member.

kicker plate A plate, 2 used to anchor a stair to
concrete.

KICKER PLATE

kicker plate

kicking piece A short timber which is fixed to
a wale so as to take up the thrust of the end of a
diagonal strut.

kickout 1 . In excavation work, the accidental
release or failure of a shore or brace. 2. At the
bottom of a vertical downspout, an elbow that
directs water away from a wall.

kickpipe A section of pipe which provides
mechanical protection for an electric cable
where it projects from a floor or deck.

kickplate 1 . A protective plate applied on the
lower rail of a door to prevent marring.
2. A vertical plate forming a lip or low curb at
the open edge of a stair platform or floor, or at
the back edge or open end of a stair tread.

kick rail A short rail mounted on a door near
its lower edge, used to kick the door open, pri-
marily on institutional doors.

kick roof A roof having flared eaves.
kick strip Same as kicker, 2.
kieselguhr See diatomite.
kill To seal, 6.

killesse Same as coulisse, 1.

kiln A furnace, oven, or heated enclosure used:

(a) for burning or firing brick and tile; (b) for

drying timber.
kiln brown stain, chemical brown stain

A brown-colored stain that develops during

kiln-drying or air-drying of lumber as a result of

changes in the wood extractives.

kiln-dried, hot-air-dried Dried or seasoned
artificially in a kiln; excess moisture has been
driven off by heating; usually has a moisture
content, 1 of 6 to 12%.

kiln-fired brick See burnt brick.

kiln-run Brick or tile, all from one kiln, which
has not been sorted or graded for size or color
variation.

kiln scum See scum.

kiln white, kiln scum A white scum that has
formed on a brick surface during firing as the result
of drier scum and kiln atmosphere. Also see scum.

kilo (k) Prefix, used in the International Sys-
tem of Units, denoting multiplication by 1000.

kilocalorie The heat required to raise 1 kilo-
gram of water 1°C; the equivalent of 1000 small
calories. Also see calorie.

kilogram The International Standard unit for
mass; equals 1000 grams.

562

kiva

kilonewton An International Standard unit of
force equal to 1000 newtons, 0.2248 kips, or
224-8 pounds.

kilovolt A unit of electromotive force equal to

1,000 volts.
kilovolt-ampere In an electric circuit, the

product of the current in amperes and the

applied voltage (expressed in volts), divided by

1,000.

kilowatt A unit of power equal to 1 ,000 watts;

equivalent to approx. 1.34 horsepower.
kilowatt- hour A unit of energy equal to 1,000

watt-hours; equal to the work expended in 1

hour at a rate of 1.34 horsepower.

kingbolt A tie rod or long bolt which takes the
place of a king post.

king closer, beveled closer A rectangular
brick, one end of which has been cut off diago-
nally to half the width of the brick (a three-
quarter brick); used as a closer in brickwork.

king closer

king piece Same as king post.

king pile l.A pile along the center line of a
wide trench which supports timbers that run to
it from both sides of an excavation. 2. A pile
which provides added support for a precast con-
crete or sheet steel pile wall.

king post l.In a truss, as for a roof, a vertical
member extending from the apex of the inclined
rafters to the tie beam between the rafters at
their lower ends. 2. See joggle post, 2.

KING POST

king post

king»post truss A structural support for a roof
formed by two inclined rafters joined at the apex
of their intersection; a horizontal tie beam, 2
connects the rafters near their lower ends, and a
vertical central member, called the king post,
connects the apex with the midpoint of the tie
beam.

king rod Same as kingbolt.

king stud A stud that is centrally located in a
gable, usually supporting the collar purlin.

king»table In medieval architecture, the string-
course, with ballflower ornaments, usually under
parapets.

kiosk l.A small pavilion, usually open, built in
gardens and parks. 2. A similar structure, often
enclosed, for the sale of merchandise such as
newspapers or magazines.

kiot In early Russian architecture, a niche to
house one or more icons.

kip A unit of force; equals 1000 pounds (4448
newtons).

kirileion A sacristy in an Eastern Orthodox
church.

kirk A church, especially in Scotland.

kiss mark A mark on a brick face produced dur-
ing firing; results from the method of stacking.

kistvaen See cistvaen.

kitchen A room intended for the preparation
and cooking of food, often where meals are also
eaten; if prepared in a structure detached from
the main house, then called an outkitchen. Also
see summer kitchen.

kitchen cabinet A case or box-like assembly
consisting of doors, drawers, and shelves primar-
ily used for storage for food, utensils, linen, etc.

kitchenette A small room or an alcove fitted
with the essential conveniences of a kitchen.

kitchen garden A private garden especially
for raising vegetables and herbs.

kit home Same as prefabricated house.

kite winder On a staircase, a winder which is
triangular in shape.

kitsch Art or architecture that is sentimental or
banal in tone; considered to have little or no
aesthetic value.

kiva In some Indian villages of the American
Southwest, an assembly room (often partly or

563

klinkart

wholly underground) which has a packed earth
floor, a firepit at its center, and a flat roof sup-
ported by hewn logs that are covered by small
branches, matting, and a layer of earth. The
room is usually entered through a roof hatchway
by means of a ladder whose poles extend well
above the flat rooftop.

klinkart A yellowish long, hard brick; primarily
used in paving.

km Abbr. for "kilometer."

kN Abbr. for kilonewton, a unit of force.

knapped flint A flint stone that has been bro-
ken or chipped to obtain a desired shape; often
set in patterns in a wall, with the split face
showing.

knapping hammer A steel hammer for
breaking stone; used for splitting cobbles and
for shaping paving stones or producing roughly
sized material; usually has two square (or rect-
angular) faces, or one such face and a wedge
peen.

knaur See knur, burl, 1.

kneading compaction The compaction of
a plastic soil by the action of a sheepsfoot
roller.

knee 1. A piece of wood having a bend, either
natural or artificially set; a crook, 2. 2. A part of
the back of a handrail having a convex upper
surface. 3. See label stop, 2.

knee brace A corner brace; a diagonal member
placed across the angle between two members
that are joined; serves to stiffen and strengthen a
framework so constructed.

CEILING
JOIST

KNEE
BRACE

knee brace

knee iron A kneepiece, 2, fabricated of iron.

kneeler, kneestone, skew l.A building
stone which is sloped on top and flat on the bot-
tom, as the stone that supports inclined coping on

kneeler, 1: K

the slope of a gable. Also see footstone; gable
springer. 2. The stone that breaks the horizontal-
vertical unit-and-joint pattern of a normal
masonry wall to begin the curve or angle of an
arch or vault.

knee piece 1. Same as knee rafter. 2. An angu-
lar piece of timber used in a roof to strengthen a
joint where two timbers meet.

knee rafter l.A principal rafter having a bend
in it. 2. A brace between a principal rafter and a
tie beam.

knee roof A curb roof.

kneestone See kneeler.

knee timber A timber having a natural curve
or knee 1 .

knee wall A wall which acts as a knee brace by
supporting roof rafters at some intermediate
position along their length; shortens the span of
the rafters.

knife-blade fuse A cartridge fuse having a
metal blade at each end of a cylindrical tube for
making contact with the fuse within.

knife consistency, knife grade A grade of
caulking or glazing compound which has the
proper firmness for application with a putty
knife.

564

knotted pillar

knife file A file having a blade-like cross sec-
tion, with a sharp edge; used to finish narrow
grooves.

knife grade See knife consistency.

knife switch A type of electric switch consist-
ing of one or more movable copper blades which
are hinged and which make contact with sta-
tionary forked contact jaws by being forced
between them.

knife switch

knob l.A handle, more or less spherical, usu-
ally for operating a lock. 2. A similar protuber-
ance, useful or ornamental, such as a boss.

knobbing, knobbling, skiffiing In stone-
cutting, a preliminary process, usually the
knocking off of pieces projecting beyond the
required dimensions.

knob bolt A door lock with a bolt controlled
by a knob on one or both sides.

knob latch A door latch with a spring bolt
controlled by a knob on one or both sides.

knob lock A door lock with a spring bolt con-
trolled by one or both knobs, and a dead bolt
controlled by a key.

knob rose A round disk or plate fastened to the
face of a door around the hole in the door
through which the doorknob spindle passes.

knob rose

knob shank The projecting stem of a knob
into which the spindle is fastened.

knob top That part of a doorknob which the

hand grasps.
knocked down (KD) Prefabricated, but not

assembled; said of items delivered to the jobsite

for assembly there.
knocked-down frame A doorframe furnished

by the manufacturer in three or more basic parts

for assembly in the field.

knocker See door knocker.

knockings In stone masonry, the smaller
pieces knocked off in dressing stone.

knocking up 1 . Preparing and mixing a batch
of concrete, mortar, or plaster. 2. The rework-
ing of a mortar mix so that it is plastic once
again.

knockout A partially punched-out circular
area in the surface of an electrical outlet, junc-
tion box, or panel box; can easily be removed
with a hammer, pliers, or screwdriver to provide
access for the attachment of a raceway cable or
fitting.

knop Same as knob, 2.

knot l.In medieval architecture, a bunch of
leaves, flowers, or similar ornament, as the
bosses at the intersections of ribs, and bunches
of foliage in capitals. 2. An ornamental design
resembling cords which are interlaced. 3. The
hard, cross-grained mass of wood formed in a
trunk at the place where a branch joins the
trunk. 4. In fabric construction, the presence
of an imperfection that will cause a surface
irregularity.

knot brush A brush having its bristles grouped

in one to three thick knots (of round or oval

shape); used for distempers.
knot»cluster A compact, roughly circular group

of three or more knots in wood, each surrounded

by contorted grain.

knot garden A complicated garden design,
usually small in area, and making use of plants
set in geometric patterns, low hedges of shrubs
trimmed into ornamental shapes as borders,
and green foliage set off by sharp color
contrast.

knothole A hole in a board or plank caused
when a knot, 3 drops out of the piece of wood.

knotted pillar, knotted shaft A form of
pillar, occurring in Romanesque architecture,

565

knotting

knotted pillar

so carved as to appear as if knotted in the
middle.

knotting, knot sealer A sealer (such as shel-
lac, aluminum paint, or varnish) for knots in
new wood; used to prevent bleed-through of
resin into paints.

knotty pine Wood of the pine tree cut so that
the knots form a decorative pattern; used for
interior paneling and cabinets.

knotwork A carved ornamental arrangement
of cord-like figures knotted together as in some
kinds of fringe, used to decorate voussoirs, mold-
ings, etc.

Etaw

knotwork

knuckle One of the cylindrically projecting
parts of a hinge through which the pin passes.

knuckle bend A bend having a short radius.

knuckle joint l.See curb joint. 2. A type of
hinged joint between two rods.

knulling 1 . A convex rounded molding of
slight projection, consisting of a series of more or
less elaborate members separated by indenta-
tions. 2. Same as knurling.

ckle

knur, knurl A knot or burl, 1 in wood.

knurling l.A series of small ridges, usually
milled on a surface, in order to provide a better
surface for gripping or turning; also called
milling. 2. Same as knulling.

KO On drawings, abbr. for knockout.

koa A hard, light red to dark brown wood with
a golden luster from the Hawaiian Islands;
takes a fine polish, being marked with wavy
lines; used for veneer, cabinets, and interior
finish.

kondo The main, "Golden Hall" of a Buddhist
monastery in Japan.

konistra In the ancient Greek theater, the
orchestra.

korina, limba A hardwood of central and west
Africa, light to moderately heavy, having a
straight grain and fine texture; one variety is
light cream to pale yellow in color, while the
other is light brown; used for paneling.

KP Abbr. for kickplate.

kPa Symbol for "kilopascal," a unit of pressure
equal to 1000 pascals.

KP&D Abbr. for "kickplate and drip."

kraft paper A heavy, high-strength paper, sized
with resin, usually brown in color; used as a
building paper.

566

kyanize

kremlin l.In Russia, the citadel of a town or
city, serving as an administrative and religious

center. 2. (initial cap.) The citadel of Moscow, a
90 acre (36 hectares) area surrounded by 15th-
century crenelated walls, entered by five
steepled gate towers.

krepidoma Same as crepidoma.

ksi Abbr. for "kilopounds per square inch."

K-truss, K-type truss A truss in which the
arrangement of the panels, 7 has the appearance
of the letter K.

^kKMCDDDHX

kremlin

K'truss

kVA Abbr. for "kilovolt-ampere."
k»value See thermal conductance.

kW 1. Symbol for "kilowatt"; a unit of power.

2. On drawings, abbr. for kilowatt.
kWh 1. Symbol for "kilowatt hour"; a unit of

energy equal to 3.6 megajoules. 2. On drawings,

abbr. for kilowatt-hour.
kyanize, kyanise To preserve wood against

decay by steeping it in a mercuric chloride

solution.

567

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L l.On drawings, abbr. for "left." 2.Abbr. for
lambert.

label course A course, 1 of bricks around the
exterior perimeter of the visible face of an arch;
placed so as to throw off rainwater that would
otherwise run down the face of the wall.

labeled 1. Carrying an identification of a rec-
ognized testing laboratory which certifies the
results of appropriate fire tests conducted on
essentially identical materials or construction,
as a labeled door, labeled frame, or labeled win-
dow. 2. According to the NEC, materials or
equipment carrying an identifying label, sym-
bol, or other identifying mark of an organiza-
tion that is acceptable to the authority having
jurisdiction. The label indicates compliance
with appropriate standards or performance in a
specified manner.

labeled door A fire-rated door carrying a certi-
fied rating by the Underwriters' Laboratories, Inc.

labeled frame A doorframe that confomrs to all
applicable requirements and tests of the Under-
writers' Laboratories, Inc., and bears their label.

labeled window A window that conforms to
all applicable requirements, in respect to fire
resistance, of the Underwriters' Laboratories,
Inc., and bears their label designating the fire
rating.

label molding, label A square-arched drip-
stone or hoodmold; extends horizontally across
the top of an opening and returns vertically
downward for a short distance.

label stop 1 . The termination of a hoodmold
or arched dripstone in which the lower ends are
turned away from the opening horizontally.
2. Any decorative boss or other termination
of a dripstone, hoodmold, sill, etc.; a knee
(Brit, colloq.).

label
molding

label
stop

label molding and label stop

label molding

label stop, 2

labor and material payment bond A bond
of the contractor in which a surety guarantees to
the owner that the contractor will pay for labor
and materials used in the performance of the
contract. The claimants under the bond are
those having direct contracts with the contrac-
tor or any subcontractor.

labor cost On a construction project, the cost
of all labor necessary to produce the construc-
tion required by the contract documents.

569

laboratory fume hood

laboratory fume hood Same as exhaust
fume hood.

labyrinth l.A maze of twisting passageways.
2. In medieval cathedrals, the representation of
such a maze inlaid in the floor. 3. A garden fea-
ture of convoluted paths outlined by hedges,
usually above eye level; also called a maze.

labyrinth, 2

labyrinth fret, key pattern, meander A

fret with many involved turnings.

labyrinth fret

lac A resinous insect secretion used as a base for
shellac, lacquer, and varnish.

laced beam Same as lattice beam; see lattice
girder.

laced column A composite column in which
the components are connected by lacing, 1 .

laced valley, woven valley A valley of a
shingle, slate, or tile roof formed by interweav-
ing shingles, slates, or tiles from the two inter-
secting surfaces.

lacewood A coarse-grained wood from Australia,
pale pink to pinkish brown in color, moderately
hard and heavy, with a lace-like figure; used for
interior trim, paneling, and plywood.

lacework Architectural decorations resem-
bling lace. Also see cast-iron lacework and jig-
saw work.

lacing 1. A system of members (e.g., bars or bat-
ten plates) used to connect two component ele-
ments of a composite girder, strut, or column to
make them act as one member. 2. Same as lacing
course. 3. Timbers placed behind or around
other supports as bracing. 4. Small boards which
close up the spaces between lagging planks or
sheeting to prevent dirt from entering an exca-
vation. 5. The interlocking of sections of sheet
pile to form a wall.

lacing course A course of brick or tile inserted
in a rough stone or rubble course as a bond course.

laconicum The sweat room in a Roman bath.

lacquer Any glossy enamel which dries quickly
by evaporation of the volatile solvents and dilu-
ents. Also see Chinese lacquer.

lacunar, laquear A coffer or coffering.

lacunaria The ceiling of the ambulatory
around the cella of a temple, or of the portico.

ladder A frame, usually of wood or metal, con-
sisting of two side pieces (called "stiles") which
are connected by crosspieces, usually round
(called "rungs"); used as a means of climbing up
or down.

ladder cable tray A continuous steel or alu-
minum support for wiring or cables.

ladder cable tray

ladder core A hollow core consisting of strips
of wood, wood derivative, or insulation board,
with the strips running either horizontally or
vertically throughout the core area and with air
cells and/or spaces between the strips; used as
the core in interior doors.

570

lambrequin

ladder ditcher See ladder trencher.

ladder jack scaffold A light-duty scaffold

supported by brackets attached to ladders.
ladder trencher A ditcher which digs trenches;

utilizes buckets mounted on a pair of chains that

travel on the exterior of a boom.
ladies' room, women's room In a public

building, a room containing toilet and lavatory

facilities for the use of ladies.

ladkin, latterkin A pointed piece of hard-
wood used for clearing out the grooves of the
cames, which hold panes of glass in stained-glass
windows and casements.

ladrillo In Spanish Colonial architecture and
derivatives, an adobe brick that has been kiln-
dried rather than sun-dried, thereby provid-
ing increased durability, increased mechanical
strength, and greater moisture protection.

Lady chapel A major chapel dedicated to the
Virgin Mary, on the axis of a church at its east end.

LAG On drawings, abbr. for lagging.

lag bolt, coach screw, lag screw A bolt
having a square head and a thin, coarse-pitched
thread.

Aluminum [ackffl buoVct masltc

Gla&L 'rber lagging

lag bolt

lagged pile A pile having longitudinal pieces
(i.e., lags) which are fastened to it for providing
mechanical protection and increased friction
and bearing area.

lagging 1. Thermal insulation for pipes, tanks,
ducts, etc.; sometimes block insulation, pre-
shaped to conform to the curved surface.
2. The planking, consisting of narrow strips,
extending from one rib of the centering of an
arch or vault to another; provides direct sup-
port for the voussoirs until the arch or vault is
closed in. 3. Boards which are joined, side by
side, lining an excavation. 4. Horizontal mem-
bers between soldier piles. 5. Wood strips that
cover a wall.

lag screw See lag bolt.

laid-dry masonry Same as dry masonry.

lagging, 1

laid-on molding, planted molding A mold-
ing that is worked separately and fastened to the
work by brads.

laid-on stop See stop, 1.

laitance The accumulation of fine particles on
the surface of fresh concrete resulting from an
upward movement of water in the concrete;
occurs when excessive water is used in the mix-
ing of the concrete.

laja In Spanish architecture and its derivatives,
same as flagstone.

lake Any of a number of bright pigments which
are prepared from animal, vegetable, or coal-tar
coloring matter, or formed synthetically; used
in paints.

lake sand Sand consisting mainly of rounded
particles as contrasted with bank sand which has
sharp edges; the latter is preferred in plastering.

Lally column A proprietary name for a cylin-
drical column which is concrete filled; used as a
structural column to support beams or girders.

LAM On drawings, abbr. for laminate.

Lamassu The monumental human-headed,
winged bulls that guarded the entrances to
Mesopotamian palaces and temples.

lambert A unit of luminance equal to ( l/n) can-
dela per sq cm; equal to the uniform luminance of
a perfectly diffusing surface emitting or reflecting
light at the rate of 1 lumen per sq cm. Abbr. L.

Lambert's cosine law A law stating that the
luminous intensity, in any direction from a
plane surface, varies as the cosine of the angle
between that direction and the perpendicular to
the surface.

lambrequin An ornamental horizontal band,
often fringed, lobed, or notched along its lower
edge.

571

lamb's-tongue

lamb's-tongue l.The end of a handrail
which is turned out or down from the rail and
curved so as to resemble a tongue. 2. A carpen-
ter's molding plane having a deep and narrow
blade more or less resembling a tongue and
curved so as to cut a quirk bead. 3. A molding
cut from such a plane, usually two ovolos sepa-
rated by a fillet and set off by fillets at the other
ends.

lamb's-tongue, 1

lamella A reinforced concrete, metal, or wood
member joined with similar members in a criss-
cross pattern so as to form an arch or vault.

lamella roof A vaulted roof-framing system
composed of lamellae.

laminar flow See streamline flow.

laminate 1 . A product made by bonding together
two or more layers of material, e.g., plywood, lam-
inated wood, etc. 2. To unite layers of material
with an adhesive.

laminated arch A wooden arch made of sev-
eral layers or laminations of thin boards bolted
or glued together.

laminated beam A beam built up by gluing
together several pieces of timber; may be either
straight or curved.

laminated glass, safety glass, shatterproof
glass Two or more plies of plate glass, float
glass, or sheet glass, bonded to a transparent
plastic sheet between them to form a shatter-
resisting assembly.

laminated joint A finger joint.

laminated plastic A plastic material consist-
ing of superimposed layers of a synthetic resin-
impregnated or resin-coated filler which have
been bonded together (usually by means of heat
and pressure) to form a single piece.

laminated timber See glued-laminated timber.

laminated wood Board or timber built up of
plies which are joined together by gluing; usually
the grain of all plies is parallel.

lamp A man-made light source which produces
radiation in or near the visible region of the spec-
trum; often called a bulb or tube to distinguish it
from the complete lighting unit consisting of the
source and associated parts such as reflectors, etc.

lamp ballast See ballast.

lamp base, Brit, lamp cap That part of a
lamp which connects to the lamp holder; pro-
vides electrical contacts.

lampblack, vegetable black A fine black
pigment consisting of particles of carbon; col-
lected from the soot of burning oil.

lamp bulb The glass envelope enclosing the
luminous element or material of an electric
lamp; usually made of glass, quartz, or similar
material; its shape usually is designated by a let-
ter (e.g., T — tubular, G — globe, etc.), followed
by a number which indicates the maximum
diameter of the bulb in eighths of an inch.

lamp cap (Brit. ) See lamp base.

lamp depreciation The decrease in luminous
output of a lamp during its operating life.

lamp holder, lamp socket A device which
mechanically supports a lamp for the purposes of
making electrical contact with the lamp.

lamp inrush current The initial surge of cur-
rent when an incandescent filament lamp is
turned on; may be as much as 50 times the rated
current and may last several tenths of a second
for high- wattage lamps.

lamp jacket The second, or outer, bulb used on
some lamps.

lamp life See rated lamp life.

lamp lumen-depreciation factor The frac-
tional loss of lumens radiated by a lamp at rated
operating conditions; because of aging, this loss
increases progressively during the lifetime of the
bulb.

lamp post A standard support for a luminaire,
provided with the necessary internal attach-
ments for wiring and the external attachments
for the bracket.

lamp socket See lamp holder.

lanai A living room or lounge area which is
entirely, or in part, open to the outdoors.

572

landscaped roof

lancet, lancet window 1. A narrow window
with a sharp pointed arch typical of English
Gothic architecture from ca. 1150 to ca. 1250.
2. One light shaped like a lancet window.

lancet

lancet arch A sharply pointed two-centered
arch whose centers of curvature are much farther
apart than the width of the arch; an acute arch.

Hi„ fa

lancet arch

lanceted Having a lancet window or arch.

Lancet style The style of Early English archi-
tecture distinguished by its use of the lancet
arch; sometimes called First Pointed Gothic.

lancet window A narrow window having the
shape of a lancet arch.

lanciform Having a sharp point.

land 1. Part of the surface of the earth not per-
manently covered by water. 2. Any immoveable
improvements or fixtures attached thereto.

land boundary A line of demarcation be-
tween adjoining parcels of land. The parcels of
land may be of the same or different ownership,
but were distinguished at one time in the history
of their descent by separate legal descriptions.

land-clearing rake A blade-like device which
is attached to the front of a tractor; used to cut
and collect brush which is removed in clearing a
construction site.

land development The process of improving
a large tract of land; includes clearing, grading,
and the installation of sewers and utilities such
as water, gas, and electricity.

land drain Same as agricultural pipe drain.

landfill The disposal of garbage, refuse, and

trash by burying it under layers of earth in low

ground or in excavated pits.
landing, pace, stair landing The horizontal

platform at the end of a stair flight or between

two flights of stairs.
landing door See hoistway door.

landing newel, angle newel A newel which
is located on a stair landing or at a point where
stairs change direction.

landing tread On a stair landing, the board
directly over the uppermost riser; has an edge
matching that of the nosing on the stair treads
and has the same overhang.

landmark l.Any building, structure, or place
that has a special character, special historic inter-
est, and/or special aesthetic interest, or value, as
part of the development, heritage, or cultural
characteristics of a nation, state, city, or town.
2. A monument, fixed object, or marker on the
ground that designates the location of a land
boundary. 3. A formal designation of such status
for a building by a national or local authority.
Also see National Historic Landmark and Na-
tional Register of Historic Places.

landscape architecture The practical art
and science of adapting land for human use and
enjoyment, based on the premises that land use
and beauty are compatible and that neither is
complete without the other. Includes the
planned combination of living plants, such as
flowers, grass, ground cover, shrubs, trees, and
vines, as well as natural features such as rocks
and stones; and may also include reflecting
pools, fountains, outdoor artwork, gazebos,
screen walls, benches or fences.

landscaped roof A roof intended to be land-
scaped; the weight of the landscaping materials
is considered to be a dead load, computed on
the basis of the soil's being saturated with water.

573

landscape improvement

landscape improvement Any physical bet-
terment of real property, or any part thereof, as a
result of natural or artificial landscaping.

landscape screen See office landscape screen.

landscape window A double-hung window

whose upper sash is decorated with small panes
of colored glass; the lower sash, of clear glass, is
a single pane and is larger than the upper sash.
land survey A survey of landed property estab-
lishing or reestablishing lengths and directions of
boundary lines. Land boundaries are usually
defined by ownership, commencing with the ear-
liest owners through successive ownerships and
partitions. Land surveying includes the reestab-
lishment of original boundaries and the estab-
lishment of such new boundaries as may be
required in the partition of the land.

land tie A tie rod or chain used to secure a
retaining wall or the like.

land tile Porous clay tile pipe laid with butt joints.

land-use analysis The study of an existing
pattern of use, within an area, to determine the
nature and magnitude of deficiencies which
might exist and to assess the potential of the pat-
tern relative to development goals.

land-use plan The projection of a future pat-
tern of use within an area, as determined by
development goals.

land-use survey A study and recording of the
way in which land is being used in an area; usu-
ally classified as commercial, industrial, public,
residential, etc.

lane 1. A narrow passageway bordered by trees,
fences, or other lateral barrier. 2. That part of a
roadway which accommodates a single line of
vehicles.

languet An ornamental band, often enriched,
consisting of a series of upright, tongue-shaped
elements.

lantern A windowed superstructure crowning a
roof or dome; a lantern light.

lantern cross A cross atop a lanterne des morts.

lanterne des morts A graveyard lantern; a
slender tower-like structure, usually in the form
of a hollow column, terminated by a pierced tur-
ret containing a light which shone through the
openings; many such towers were in France in
medieval times.

lantern

lanterne des morts

574

lap weld

lantern light A relatively small structure, hav-
ing openings in its sides, above the roof of a
building to provide light on its interior.

lantern skylight A small skylight atop a build-
ing to provide light and ventilation in the space
below.

lantern-type chimney The top of a chimney
shaft whose sides are pierced near the top to
carry away the products of combustion, rather
than their being carried away through the top of
the chimney, which is covered.

lanthorne See cupola.

lap l.To overlap or partly cover one surface
with another, as in shingling. 2. The length of
the overlap, as the distance one tile extends over
another.

lap adhesive An adhesive used to seal the laps
and sides of a jacket that surrounds thermal insu-
lation around a pipe.

lap cement A type of asphalt used as an adhe-
sive between the laps of roll roofing.

lap dovetail Same as lapped dovetail.

lapies A bedrock surface, beneath the soil,
roughened as a result of action by a solution of
limestone, gypsum, or other soluble rock; usually
deeply trenched along joints. Such a bedrock
presents hazards and results in excessive costs for
footings and foundations.

lapis Same as milliarium.

lapis lazuli A rich blue semiprecious stone;
either used decoratively or ground and powdered
for use as an ultramarine pigment.

lap joint 1. A joint in which one board, plank,
metal plate, etc., overlaps the edge of another
piece; the overlapping part of each member is
cut away to half thickness, resulting in flush sur-
faces. 2. A joint formed by placing one piece
partly over another and uniting the overlapped
portions.

lapped dovetail, drawer dovetail A dove-
tail at an angle in which the pegs of one member
do not pass through the full thickness of the
other; esp. used at the front of a drawer.

lapped dovetail

lapped tenons Two tenons which enter a com-
mon mortise from opposite sides and overlap one
another.

lappet One of a series of pendants trimming the
eaves of a roof.

lapping In reinforced concrete, the overlap-
ping of steel reinforcing bars, or other rein-
forcement, so there is continuity of tensile
stress in the reinforcement when the concrete
member is subjected to a flexural or tensile
load.

lap-riveted Said of two plates overlapped and
then joined by riveting.

lap scarf A flush j oint formed by fitting one end
of a length of wood gutter into the opposite end
of another.

lap seam A joint formed by overlapping the
edges of metal sheets or plates and joining them
by riveting, welding, soldering, or brazing.

lap siding See clapboard.

lap splice 1. A connection of reinforcing steel
made by lapping the ends of bars. 2. A splice
made by placing one piece on top of another and
fastening together with pins, nails, screws, bolts,
rivets, or similar contrivances.

lap weld A weld in which the ends of the
pieces are overlapped and then joined by

welding.

lap joint, 2

lap notch Same as half-cut notch.

lap weld

575

laquear

laquear Same as lacunar.

lararium In Roman houses, a small shrine to
the household gods (lares).

larch, tamarack A fine-textured, strong, hard,
straight-grained wood of a coniferous tree; heav-
ier than most softwoods.

larder A room where food is stored.

large calorie The heat required to raise 1 kilo-
gram of water 1°C; equivalent to 1000 small
calories or 1 kilocalorie.

large knot A knot in wood which is greater
than 1 J/2 in. (3.8 cm) in diameter.

larmier, lorymer l.A corona. 2. Any hori-
zontal member or stringcourse similar in profile
to a corona and projecting from a wall to throw
off rain; a roll molding, drip, etc.

larnite A mineral which is a major constituent
of portland cement; beta dicalcium silicate.

larry A hoe having a long handle and a blade
which usually is perforated; used for mixing mor-
tar or plaster.

larrying, larrying-up In masonry construc-
tion, the laying of bricks by sliding the bricks into
appropriate positions (for example, between the
inner and outer walls of a cavity wall) and then
filling the space between with mortar.

laser A device that emits a powerful beam of
coherent light in an intense beam; used, for
example, on building projects to provide a
means of ensuring that construction is along a
straight line, or to ensure that the construction
is carried out to precisely the same height.

LAT 1. On drawings, abbr. for "latitude." 2. On
drawings, abbr. for "lateral."

lat In Indian architecture, an isolated shaft or
pillar serving various purposes, as for bearing
inscriptions or religious emblems or for a statue
or image.

latanier In the architecture of the southeast-
ern US, palmetto fronds employed as a roof
covering.

latch A simple fastening device having a latch
bolt, but not a dead bolt; contains no provisions
for locking with a key; usually openable from
both sides.

latch bolt A spring bolt, one edge of which is
beveled; when the door or window to which it is
attached is closed, the bolt is forced inward;

simple latch

when in the fully closed position, the bolt
springs back into a fixed notch or cavity.

latchet Same as tingle, 2.

latchkey A key used to raise and throw back
the latch of a door.

latch plate An escutcheon that protects the
area of a door around a latch.

latchstring A string for raising the latch of a
door from the outside; it is fastened to the
latch and passed through a hole above it in the
door.

Late Georgian style See Georgian style.

Late Gothic Revival The last phase of the
Gothic Revival in the early part of the 20th cen-
tury, in which an attempt was made to emulate
its Gothic architecture prototype with some
degree of accuracy; for example, see Collegiate
Gothic.

latent heat The amount of heat which is
absorbed or evolved in changing the state of a
substance without changing its temperature,
e.g., in freezing or vaporizing water.

later A brick, formed in a mold and dried in the
sun or baked in a kiln by the early Greeks and
Romans; much larger and much thinner than
modern bricks; each brick was stamped with the
name of the maker and the year in which it was
made.

lateral Same as lateral sewer.

lateral buckling, lateral-torsional buck-
ling The buckling of a structural member
which involves lateral deflection and twist.

lateral buttress A buttress that stands at one
corner of a building.

lateral drift Same as drift, 1.

576

lath scratcher

lateral load l.See wind load. 2. See earth-
quake load.

lateral pressure The pressure, acting in the
lateral direction, exerted by the retained soil
against a structure.

lateral reinforcement That part of the steel
reinforcement for a reinforced concrete col-
umn in the form of transverse hoops, links, or
helixes around the vertical reinforcing steel
rods.

lateral restraint The restraint that limits lat-
eral movement of the compression flange of a
beam.

lateral scroll A fitting which curves in a hori-
zontal plane and is used to terminate a stair
handrail.

lateral sewer A sewer which discharges into a
branch or other sewer and has no other common
sewer tributary to it.

lateral support The bracing for a wall, beam,
or structural member, either horizontal (by roof
or floor constructions) or vertical (by pilasters,
columns, or cross walls).

lateral-torsional buckling See lateral buck-
ling.

later crudus A brick baked in the sun rather
than in an oven.

latericius Built of brick.

lateritum opus Brickwork of the ancient
Romans.

Late Rococo See Neo-Rococo.

latest event occurrence time In CPM ter-
minology, the deadline by which time an event
must be completed if the project is not to be
delayed.

latest finish date In CPM terminology, the
latest point in time by which no further work
must be done on an activity if the project is not
to be delayed.

latest start date In CPM terminology, the lat-
est possible point in time by which an activity
must be started if the project is not to be
delayed.

Late Victorian architecture A term occa-
sionally applied to architecture in the Queen
Anne style. See Victorian architecture.

latewood See summerwood.

latex An emulsion of finely dispersed particles
of natural or synthetic rubber or plastic materials
in water.

latex foam Sponge rubber made from latex.

latex mortar An admixture used as an ingre-
dient in a batch of mortar-mix to retard its
setting.

latex paint A paint containing latex in a water
suspension (i.e., natural or synthetic rubber or
plastic particles suspended in water) combined
with pigments and other additives acting as
binders.

latex patching compound A compound
which consists of a latex (usually styrene-
butadiene rubber), portland cement, and an
aggregate; moisture-, mildew-, and alkali-resis-
tant; used for patching or leveling a floor.

latex sealant A compound of latex which cures
primarily through water evaporation.

lath A building material used as a base for the
application of plaster; see expanded metal lath,
gypsum lath, metal lath, split lath, wood lath.

lath brick A long, narrow brick.

lathe A machine for shaping circular pieces of
wood, metal, etc., by rotating the material about
a horizontal axis while a stationary tool cuts
away the excess material.

lath hammer, lathing hammer, lathing
hatchet A hammer which has a small
hatchet blade on the side opposite the hammer
head; the blade has a small lateral nick for
pulling out nails; esp. used for cutting and nail-
ing wood lath.

lathhouse A structure made of laths or slats to
shelter growing plants requiring shade and wind
protection.

lathing 1. A quantity of laths. 2. The erecting
or placing of laths.

lathing board See backup strip.

lathing hammer, lathing hatchet See lath
hammer.

lath laid-and-set In plastering, a method of fin-
ishing the ceilings and partitions of houses with
two-coat work, in which the first coat is called
laying, and is often scratched with a broom.

lath scratcher A tool, made from pieces of
wood lath, for scratching and roughening base-
coat plaster to improve the bond of the next coat.

577

latia

latia In Spanish Colonial architecture, one of a
number of light, relatively straight saplings,
usually about 3 feet (1 m) long, that has been
stripped of its bark and laid across log beams
(vigas) of a structure, either diagonally so as to
create a herringbone ceiling pattern or laid at
right angles to the vigas. A matting of reeds,
placed over the latias, is then covered with a
layer of tamped earth, dried mud, or adobe
mixed with grass, to serve as a roof.

latia labrada A latia that has been split along
its length; usually laid across vigas with its flat
side down.

Latin cross A cross with the vertical bar sub-
stantially longer than the horizontal bar.

latitude 1 . The perpendicular distance in a hor-
izontal plane of a point from an east-west axis of
reference. 2. In surveying, the north-south com-
ponent of a traverse course.

latrina An ancient Roman term for a bath or
place to wash, or a water closet in a private home.

latrine 1 . A public toilet. 2. A privy.

latrobe A stove or heater set under a mantel-
piece, heating the room by direct radiation and
one or more rooms above by hot air.

latten An alloy of copper and zinc; yellow in
color, resembling brass.

latterkin See ladkin.

lattice l.A network, often diagonal, of strips,
rods, bars, laths, or straps of metal or wood, used
as screening or for airy, ornamental construc-
tions. 2. A regular member triangularly braced,
e.g., a lattice girder, a lattice truss.

lattice beam See lattice girder.

lattice boom A boom of lattice-type construc-
tion, usually fabricated of steel angles or tubing.

lattice girder, lattice beam An open girder
in which the web consists of diagonal pieces
arranged like latticework.

lattice molding A wood molding, rect-
angular in section and broad in relation to its
projection, resembling the wood strips used in
latticework.

lattice porch A porch enclosed by a lattice,
usually of wood strips; provides limited privacy,
yet permits breezes to flow through the porch.

lattice truss A truss consisting of upper and
lower horizontal chords, connected by web

members which cross each other; usually stiff-
ened by joining at the intersections of the
braces.

lattice window A window casement, fixed or
hinged, with glazing bars set diagonally.

latticework Reticulated or net-like work formed
by the crossing of laths or narrow, thin strips of
wood or iron, usually in a diagonal pattern.

lauan See Philippine mahogany.

laundry chute, clothes chute A shaft for
conveying soiled clothing, bed linen, etc., by
gravity from an upper to a lower floor of a
building.

laundry room A room equipped with one or
more washing machines, washtubs, driers, iron-
ing boards, etc., for household linen and/or per-
sonal effects.

laundry tray, laundry tub, set tub A deep
wide sink or tub, usually of porcelain, slate, or
soapstone; used for washing clothes, etc.

laundry tray

LAV On drawings, abbr. for lavatory.

lavabo In monasteries of the Middle Ages, a
large stone basin from which the water flowed
through a number of small orifices around the
edges, for the convenient performance of ablu-
tions before religious exercises or meals.

lavacrum A place for washing.

lavatory l.A basin with water supply and
drainage piping, for washing the hands and
face; a washbasin. 2. A room containing a
washbasin and a water closet, but not a bath-
tub; a "powder room." 3. Same as toilet, 2 or

578

laying out

lavabo: Abbey of Valmagne

water closet, 2. 4. A small stone basin with a
hole at the bottom to carry off water through a
drain beneath; usually placed near the altar in
an ancient church; used by the priest for wash-
ing his hands.

EFFECTIVE^ (

lavatory, 1

lavatory, 4

lavra 1. A Greek Orthodox monastery. 2. In a
monastery, an assemblage of cells for monks
around a common center that contains a church
and sometimes a refectory.

lawn 1. An open space of ground of some size,
covered with grass and kept smoothly mown.
2. Same as gauze, 2.

lawn sprinkler system A system of devices,
usually installed below ground level, to scatter or
spray water droplets over a lawn, golf course, or
the like.

law of reflection As applied to rays of light,
sound, or radiant heat which strike a surface:
the angle of reflection is equal to the angle of
incidence, and the reflected and incident rays
are in the same plane with a perpendicular to
the surface.

lay bar A horizontal glazing bar.

lay board A board which is fixed on the rafters of
a pitched roof to take the feet of the rafters, form-
ing a subsidiary roof transverse to the main roof.

layer Same as course.

layer board Same as lear board.

laying See lath laid-and-set.

laying length The length of an installed
pipeline, measured along its centerline.

laying off The elimination of roller marks or
brush marks on a wet paint surface by the appli-
cation of light brush strokes.

laying-off angles In surveying, rotating a
level to measure the angle between two inter-
secting lines.

laying out The marking of a material, indicat-
ing where cuts are to be made, in preparation for
work to be done.

579

laying to bond

laying to bond Laying all the bricks in one
course without the use of a cut brick.

laylight A glazed opening in a ceiling to admit
light (either natural or artificial) to a room below.

layout A plan showing a scheme for an arrange-
ment of objects and spaces.

lay panel A wall panel whose horizontal
dimension is greater than its vertical dimension.

lay-up 1. In reinforced plastics, the reinforcing
material placed in position in the mold. 2. The
resin- impregnated reinforcement. 3. The assem-
bling of veneers for fabrication as plywood.

lazaret, lazarette, lazaretto, lazar house A
segregated area for infectious medical patients,
esp. for their quarantine.

lazy susan A circular, revolving shelf; some-
times used in corner kitchen cabinets.

lb Abbr. for "pound."

L-beam A beam whose section has the form of
an inverted L; usually placed so that its top
flange forms part of the edge of a floor.

Lbr Abbr. for lumber.

LCL 1. Abbr. for light center length. 2. Abbr. for
"less than carload."

LCM Abbr. for loose cubic meter.

L&CM Abbr. for "lime and cement mortar."

L-column That portion of a precast concrete
frame composed of the column, haunch, and
part of the girder.

LCY Abbr. for loose cubic yard.

LDG On drawings, abbr. for landing.

leaching 1. The process of separating a liquid
from a solid (as in waste liquid) by percolation
into the surrounding soil. 2. The process of allow-
ing soluble nutrients to move downward and per-
colate through the surrounding soil.

leaching basin A drainage pit with sand
and gravel sides constructed to allow water to
dissipate.

leaching cesspool A cesspool, 1 in which the
solids present are retained and the liquid seeps
into the surrounding soil.

leaching field Same as absorption field.

leaching pit See leaching well.

leaching well, leaching pit A pit, or a recep-
tacle having porous walls, which permits its liquid
contents to seep into the ground, but retains the
solids.

leaching cesspool

lead l.One of the sections of a masonry wall
built up at each corner; supports a line between
them which serves as a guide for constructing
the remainder of the wall. 2. (pi.) See leads.
3. A soft, malleable, heavy metal; has low melt-
ing point and a high coefficient of thermal
expansion; very easy to cut and work.

lead bat See lead wedge.

lead burning The welding of sheet lead.

lead-capped nail Same as lead head nail.

lead chromate One of a series of opaque pig-
ments, orange to yellow in color, with high tint-
ing strength.

lead chrome green See Brunswick green.

lead-covered cable An electric cable
which is provided with a covering of lead to

lead-covered cable

580

lead-lined frame

exclude moisture and to provide mechanical
protection.

lead damp course A damp course fabricated
of sheet lead.

lead dot A device for fastening sheet lead to a
stone surface.

lead drier One of many organic lead salts
which are soluble in paints and varnishes; used
to speed the drying and hardening of the oil
vehicle.

leaded brass An alloy of copper and zinc
to which lead has been added to improve
machinability.

leaded glass See leaded light.

leaded joint A plumbing joint that is sealed by
pouring hot lead around it.

leaded light A window having small diamond-
shaped or rectangular panes of glass set in lead
cames.

leaded zinc oxide One of a series of mixed
white pigments consisting of zinc oxide and
basic lead sulfate; used principally in exterior
house paints.

leader 1. A downspout. 2. A duct for conduct-
ing hot air to an outlet in a hot-air heating
system.

leader: L; leader head, H; leader shoe, S; leader strap, T

leader head, conductor head, rainwater
head An enlargement or catch basin to
receive rainwater from the gutter at the top of a
leader.

leader head

lead flat A flat roof which is covered by lead
sheet laid over boarding.

lead foil tape A tape, typically about Vi inch
wide and 0.002 inch thick (12.5 mm X 0.05 mm),
which is cemented to a window or panel to detect
its breakage; forms part of an alarm circuit
through which a small electric current flows. If
the window or panel is broken, the tape is severed
and the circuit is interrupted, thereby activating
an alarm.

lead-free paint A paint which contains no
white lead or similar lead compounds.

lead glazing A leaded light.

lead head nail A roofing nail having a plain

shank; makes a leakproof joint when driven

through a metal roof.
leading A method of setting small panes of glass

in a window with cames fabricated of lead.

leading edge, lock edge, strike edge The

vertical edge of a swinging door or window

which is opposite the hinge edge.
lead in oil White lead ground in linseed oil;

formerly in wide use, now replaced largely by

titanium dioxide pigments.
lead joint A joint in a water pipe in which

molten lead has been poured, as in a bell-and-

spigot joint.
lead-lag ballast A ballast for two fluorescent

lamps, one of which operates on leading current

and the other on lagging current; tends to reduce

the stroboscopic effect.
lead-lined door, radiation-retarding door

A door which is lined internally with lead sheets

to prevent the penetration of x-ray radiation.
lead-lined frame, radiation-retarding frame

A doorframe internally lined with sheet lead to

581

lead monoxide

prevent the penetration of x-ray radiation; always
used with lead-lined doors.

lead monoxide Same as litharge.

lead nail A nail for fixing a lead sheet to a roof.
Such nails are often fabricated of a copper alloy.

lead naphthenate A liquid drier added to
paints containing drying oils to promote rapid
drying and hardening.

lead paint Any paint containing white lead.

lead pipe Pipe fabricated from 99.7 percent pig
lead; various lead alloys are also available for
special applications such as drainage. Lead pipes
are interconnected by wiped joints, burned
joints, or flanged joints.

lead pipe cinch An easy type of joint used in
fabricating pipe from elongated sheets of lead.
First, the lead sheets are formed in a cylindrical
shape with a flat overlap perpendicular to the
cylinder; then, the flat overlap is folded over and
crimped, thereby forming a sealed joint.

lead plug 1. A small cylinder of lead which is
forced into a hole in a masonry wall; serves as a
point of attachment for a screw or nail driven into
it. 2. A piece of lead between adjacent stones, for
holding them together; formed by pouring molten
lead in a groove cut in the jointing faces.

lead primer See red lead.

lead roof A flat roof covered with sheet lead.

leads Short lengths of electric conductors, usu-
ally insulated; usually used in the plural.

lead safe See drip sink.

lead-sheathed cable Same as lead-covered
cable.

lead shield A type of anchor, for an expansion
screw or bolt, which consists of a lead sleeve that
surrounds it.

lead slate, copper slate, lead sleeve A
cylindrical sleeve, formed of sheet lead or sheet
copper, used around a pipe where it penetrates a
roof to make the intersection watertight.

lead sleeve See lead slate.

lead soaker See soaker.

lead spitter A tapered connector between a
lead gutter and a downpipe.

lead tack 1. A lead strip used to secure the free
edge of flashing; one end of the tack is fixed to
the structure and the other end is folded over the
free edge of the sheet metal. 2. A rectangular

piece of lead which is attached to a lead pipe and
enables it to be secured to a wall or other support.

lead-up Same as starter frame.

lead wedge A tapered strip of lead used to

secure a flashing to a masonry wall.
lead wing In patent glazing, a strip of lead

around a pane of glass to secure it and to prevent

the entry of water.
lead 'wool A wool-like material of fine strands

of lead; sometimes used as caulking in pipe joints.

LEAD
WOOL

OAKUM
CALKING

lead wool applied as caulking

leaf 1. A hinged part; a separately movable divi-
sion of a folding or sliding door. 2. One of a pair
of doors or windows. 3. One of the two halves of
a cavity wall.

leaf and dart, heart and dart In Greek
architecture and derivatives, a pattern of alter-
nating, conventionalized, deltoid and lanceolate
leaves, usually applied to a cyma reversa.

leaf and dart

leaf and square A small tool used by plasterers
in ornamental work; has a leaf-shaped blade at
one end and a rectangular blade at the other.

leak See sound leak.

lean clay A clay having low values of liquid
limit and plasticity index.

lean concrete Concrete of low cement content.

leaning tower A tower, usually detached and
slender for its height, which overhangs its base;
the most famous example of such a tower is at

582

ledger

Pisa, Italy, where the 179 ft (54.6 m) tower is
16.5 ft (5 m) out of perpendicular.

lean lime An impure lime; has lower plasticity
than pure lime.

lean mix, lean mixture l.A concrete or
mortar mixture with relatively low cement con-
tent. 2. A plaster which is not workable.

lean mortar Mortar which is deficient in
cementitious components; is sticky and adheres
to the trowel; is difficult to spread.

lean»to A small extension to a building with a
roof (having but one slope) whose supports lean
against the building.

lean-to

lean»to house A seldom-used term used for a
saltbox house.

lean-to roof, half-span roof A roof having a
single pitch, carried by a wall which is higher
than the roof.

lear board, layer board A board which is
fixed across the rafters to provide a bearing sur-
face for a roof gutter lining.

lease A contract transferring the right of posses-
sion of buildings, property, etc., for a fixed period
of time, usually for periodical compensation
called rent.

leaseback See sale-and-leaseback.

leasehold A tenure by lease; real estate held
under a lease.

LECA Abbr. for "light-expanded clay aggregate."

Le Chatelier apparatus A device used in
the testing of hydraulic cements to measure
soundness, 2.

lecithin A liquid, obtained in refinement of
soya beans or cottonseed; used in paints to pro-
mote pigment wetting and to control pigment
settling and flow properties.

lectern In a church or lecture hall, a stand with
a slanting top to hold a book, speech, or music at
the proper height for reading.

lectorium The site in a Christian church
where parts of the Scripture are read.

LED Abbr. for light-emitting diode.

ledge 1. A small projecting member or molding.
2. A wood member across a number of boards to
hold them together. 3. An unframed member
which stiffens a board, or a series of boards or
battens. 4. See bedrock.

ledged-and-braced door A batten door
with diagonal bracing to provide additional
reinforcement.

ledged door Same as battened door.

ledgement table, ledgment table A band
course, stringcourse, or belt course, usually
molded; esp. one carried along the lower portion
of a building.

ledger 1 . In formwork, a horizontal member
which is supported by hangers or by upright
posts and carries joists. 2. A horizontal member
which is housed in the studs of balloon framing
and carries joists. 3. In scaffolding, one of the
horizontal members fastened to uprights which
support the put-logs and which are at right
angles to the wall; they carry the boards on
which the workmen stand. 4. A flat slab of
stone, such as that laid horizontally over a grave.

LEDGER FOR FLOOR
SLAB FORM JOISTS

ledger, 1

JOIST

WOOD GIRDER

LEDGER

ledger, 2

583

ledger board

ledger board l.A ribbon strip. 2. One of a

number of horizontal boards, joined by vertical
supports, as in a fence.

ledge rock Same as bedrock.

ledger plate 1. Same as ledger strip. 2. Same as
ledger, 1.

ledger slab A stone slab set flush in the floor of
a church.

ledger strip l.On a beam which carries joists
flush with the upper edge of the beam (or
girder), a strip of lumber which is nailed to the
side of the beam (along its bottom edge), form-
ing a seat for the joists and helping to support
them. 2. A ribbon strip.

ledgment, ledgement A horizontal, decora-
tive stringcourse of brick or stone.

left-hand door See hand.

left-hand lock A lock for use on a left-hand
door.

left-hand reverse door See hand.

left-hand stairway A stairway having the rail
on the left side, in the ascending direction.

legal open space An open space on a premise,
such as a yard or court that is permanently dedi-
cated to public use, and that abuts the premise.

leg drop A narrow curtain, usually hung as one
of a pair, on each side of a theater stage, parallel
to the footlights.

legget, leggatt A tool used by reed thatchers to
align the reeds.

legitimate house A theater in which stage
plays are produced professionally.

lehr A long tunnel-shaped oven used in anneal-
ing glass, usually in a continuous process.

Leipzig yellow See chrome yellow.

leisure stairs Stairs having an unusually small
slope.

LEMA Abbr. for "Lighting Equipment Manu-
facturers' Association."

lemon spline A strip of wood or metal, shaped
like a slice of a lemon, which is inserted in a slot
formed by two members, each of which is
grooved and butted against the other.

lengthening joint Any joint (e.g., a halved,
lapped, or scarfed joint) used to increase the
length of a timber.

lemon spline

lens 1. A glass or plastic having smooth, regular
opposite surfaces, shaped to control transmitted
light by refraction; used in a lighting unit to
focus, disperse, or collimate light rays. 2. A com-
bination of such elements.

lens panel, lens plate A transparent material
in which an array of individual lens elements has
been formed; covers lamps in a luminaire to con-
trol the direction of emitted light.

leopardwood Same as letterwood.

leper's squint See low-side window.

Lesbian cyma A cyma reversa.

Lesbian leaf Same as water leaf, 2.

lesche In ancient Greece, a public portico, club-
house, or the like, frequented by the people for
conversation or the hearing of news; such build-
ings were numerous in Greek cities, and their
walls often were decorated by celebrated painters.

lesene See pilaster strip.

lessee The person receiving a possessory inter-
est in buildings, property, etc., by lease.

lessor The person granting a possessory interest
in buildings, property, etc., by lease.

let in In joinery, to insert, to embed, or to house;
to secure a timber by inserting it in another.

let-in brace A diagonal brace that is let in
to a stud.

letter agreement, letter of agreement A

letter stating the terms of an agreement between
addressor and addressee, usually prepared to be
signed by the addressee to indicate his accep-
tance of those terms as legally binding.
letter box Same as mail box.

letter-box backplate A plate, attached to the
interior side of a door, which permits the passage

584

level transit

of mail but conceals the opening in the letter-
box plate.

letter-box hood Same as letter-box backplate.

letter-box plate, letter plate A plate, attached
to the exterior side of a door, having an opening
through which mail may be passed; often has a let-
ter-box backplate.

letter chute See mail chute.

letter-drop plate A letter-box plate, often with
a letter-box backplate.

letter of intent A letter signifying an intention
to enter into a formal agreement, usually setting
forth the general terms of such agreement.

letter plate See letter-box plate.

letter slot See mail slot.

letterwood, leopardwood, snakewood A

mottled wood of Guiana; has high elasticity;

used for decorative veneer.
letting of bid See bid opening.
levecel An appentice.

level 1 . A surveying instrument for measuring
heights with respect to an established horizontal
line of sight; consists of a telescope and attached
spirit level, a rotatable mounting, and a tripod.
Also see wye level and dumpy level. 2. The
position of a line or plane when parallel to the
surface of still water. 3. See spirit level. 4. Of
an acoustical quantity, 10 times the logarithm
(base 10) of the ratio of the quantity to a refer-
ence quantity of the same physical kind.

level control A series of bench marks or other
points of known elevation, established through-
out a project.

leveling 1. In paints, see flow, 3. 2. A surveying
procedure of determining the difference in ele-
vation between two points by means of a level or
transit and a leveling rod. A spirit level is used
on the level or transit to establish a horizontal
line of sight.

leveling coat A thin coat of plaster to provide
a level surface.

leveling course See asphalt leveling course.

leveling device On an elevator car, a mecha-
nism which automatically controls the move-
ment of the car near a landing so that the car
stops at the landing.

leveling instrument An instrument to deter-
mine the differences in elevation between points.

leveling plate A steel plate placed atop a
foundation on which a structural column may
rest.

leveling rod, leveling staff A straight rod or
bar, designed for use in measuring a vertical dis-
tance between a point on the ground and the line
of collimation of a leveling instrument which has
been adjusted to a horizontal position; usually
made of wood and has a flat face which is gradu-
ated in terms of some linear unit and fractions
thereof, the zero of the graduations being at one
end of the rod; may have the graduations on a
metal face. On some rods the graduation marks
are designed to be read by the observer at the
leveling instrument; another type, a "target rod,"
carries a target which is moved into position
according to signals made by the man at the
instrument; when the target is bisected by the
line of collimation, it is read by the rodman.

leveling rod

leveling rule A very long level, used by plas-
terers to indicate whether any part of a horizon-
tal surface is higher than another.

leveling staff See leveling rod.

level surface A surface which at every point is
perpendicular to a plumb line or the direction in
which gravity acts; parallel to the surface of still
water.

level transit Same as level, 1.

585

lever arm

lever arm In a structural member, that length
of the member between the center of the tensile
reinforcement and the center of action of the
compression.

lever board Same as louver board.

lever handle In builders' hardware, a horizon-
tal handle for operating the bolt(s) of a lock.

lever shears See alligator shears.

lever tumbler A flat tumbler in a lock; has a
pivoted motion which is actuated by the turning
of the key, thereby controlling the lock.

lever-type operator In a casement window, a
substitute for a roto operator.

Levittown In the years following World War II,
a bedroom community built in suburban New
York City, eventually becoming one of the most
successful garden communities of its type and
often replicated; characterized by winding
streets and affordable houses, each on its own
site and having an attached carport.

lewis Any of several metal devices used in hoist-
ing stone blocks, columns, or other heavy
masonry units; consists of a dovetailed tenon,
made in sections, which is fitted into a dove-
tailed recess cut in the masonry unit.

lewis bolt 1. A bolt with a wedge-shaped end
inserted like the shank of a lewis in a hole
drilled in a stone and fastened therein by pour-
ing melted lead or concrete into the unfilled
part of the hole. 2. An eyebolt similarly inserted
and used like a lewis for lifting heavy stones.

lewis hole A dovetailed recess which is cut in a
masonry unit for the reception of a lewis.

lewising tool A masonry chisel used for cut-
ting lewis holes.

LFT Abbr. for "linear foot."

LG On drawings, abbr. for "long" or "length."

lgr In the lumber industry, abbr. for "longer."

lgth In the lumber industry, abbr. for "length."

LH On drawings, abbr. for "left hand."

L-head The top of a shore which is formed with
a braced horizontal member projecting on one
side, forming an inverted L-shaped assembly.

liability insurance Insurance which protects
the insured against liability on account of injury
to the person or property of another.

Liberty See Neo-Liberty and Stile Liberty.

library A place for maintaining a permanent
collection of books for public or private use; in a
home, usually consists of a single room, but in a
public or private facility, may occupy an entire
building.

LIC On drawings, abbr. for "license."

license A written document authorizing a per-
son to perform specific acts, such as the con-
struction or alteration of a building, or the
installation, alteration, use, and/or operation of
service equipment therein.

licensed architect See architect, 2.

licensed contractor A person or organiza-
tion certified by governmental authority, where
required by law, to engage in construction con-
tracting.

licensed engineer See professional engineer.

lich-gate See lych-gate.

lich-stone See lych-stone.

lien A right enforceable against specific prop-
erty to secure payment of an obligation.

lien waiver See waiver of lien.

lierne rib In Gothic vaulting, any small subor-
dinate rib which is inserted between the main
ribs, more often as an ornament than for reasons
of construction.

lierne vault A vault in which lierne ribs are
used.

life cycle That period of time over which a
building or piece of equipment can be reason-
ably expected to carry out its intended function.

586

ligger

lierne ribs

life cycle cost The cost of a building or equip-
ment (or the like) based not only on the initial
expenditure, but also on its maintenance and
operating costs over its entire lifetime.

life performance curve For a source of light,
a curve showing the variation of some character-
istic of the source throughout its lifetime (e.g.,
lumens vs. life).

lift shaft Same as elevator hoistway.

lift 1 . An elevator used on the stage of a the-
ater, in the orchestra pit, or on the apron.
2. British term for elevator. 3. A handle or pro-
jection from the lower sash in a hung window,
used as a grip in raising the sash; also called a
sash lift. 4. One of a number of frames of scaf-
folding erected one above another in a vertical
direction. 5. The concrete placed between two
consecutive horizontal construction joints;
usually consists of several layers or courses.
6. In reinforced concrete construction, that
portion of a wall, pier, abutment, etc., placed in
a single pour. 7. The amount of grouting or mor-
tar placed at a single time in a building structure.
8. In a multi-level excavation, a bench or step.

lift gate A gate that opens by moving in a verti-
cal direction, in contrast to one that swings
about hinges along one edge.

lift hole A small hole in a pipe or pipe section
which is used to insert a device for handling
the pipe.

lifting, raising In paints, the softening and
swelling of a film of old dry paint when a new
topcoat is applied over it.

lifting beam Same as strongback.

lifting pin A lewis.

lift joint The joint formed between two succes-
sive lifts, 5.

lift latch, thumb latch A type of door latch
which fastens a door by means of a pivoted bar
that engages a hook on the doorjamb; a lever
which lifts the pivoted bar is used to unfasten
the door. Also see Norfolk latch, Suffolk latch,
thumb latch.

lift latch

lift-off butt hinge A special type of butt hinge

which has a pin permitting the door to be raised
off the hinge.

lift-off hinge See loose-joint hinge.

lift platform Same as elevator car platform.

lift shaft See hoistway.

lift slab 1. A method of concrete building con-
struction in which floor (and roof) slabs are cast,
usually at ground level, and then raised into
position by jacking. 2. A slab which is a compo-
nent of such construction.

lift 'well British term for elevator hoistway.

ligger 1 . A horizontal timber secured to
uprights and supporting floor timbers, scaffold-
ing, or the like; a ledger. 2. A long stick (often
of willow) used along the ridge of a thatched
roof. 3. A mortar board. 4. A board pathway
over a ditch.

587

light

light l.An aperture through which daylight is
admitted to the interior of a building. 2. A pane
of glass, a window, or a compartment of a window.

3. An artificial source of illumination. Also see
ceiling light, dead light, divided light, dome light,
elliptical fanlight, fanlight, lantern light, leaded
light, pavement light, quarter-round light, semi-
circular light, semielliptical light, sidelight, sky-
light, sodium light, sunburst light, transom light.

4. A spirelight.

light alloy Any alloy of aluminum.

light bridge A bridge, 3, fixed or suspended
above a theater stage, to which lighting equip-
ment is attached and/or from which it is operated.

light bulb l.Same as incandescent lamp.
2. See lamp bulb.

light-center length The distance between the
center of the light-generating element of a lamp
(e.g., the filament of an incandescent lamp) and
an arbitrary point on the lamp base; for each
type of lamp base, the reference point is defined
by convention.

light control-console A console, 3, in an
auditorium, usually with a view of the stage; used
to control the lighting — in the auditorium and
on the stage.

light court A recess formed by the outer walls
of a building and used to provide light and air
through windows to adjoining spaces within the
building.

light dimmer Same as dimmer.

light-emitting diode A solid-state device
(diode) that emits light of a single primary color,
but in combination with other diodes can produce
colors of any hue for use in signage. These devices,
each of which is about one centimeter (half- inch),
have a remarkably long life. Also called an LED.

lightfast Descriptive of paint or pigment which
is color-stable when exposed to sunlight.

light filter A device for changing the magni-
tude and/or the spectral composition of the radi-
ant light flux which is transmitted through it;
designated as selective (colored) or neutral,
according to whether or not the spectral distri-
bution of the incident flux is altered.

light-gauge steel A cold-rolled steel product,
commonly available in the shape of flat sheets,
angles, or channels; often used to frame non-
structural partitions.

light globe See globe.

light hard bricks Bricks that are not the hard-
est ones in a kiln; thus are less able to withstand
changes in temperature than are hard-burnt
bricks.

light-hazard occupancy An occupancy in
which the quantity and/or combustibility of its
contents is low; if a fire should occur, a relatively
low rate of heat release is expected.

lighthouse A tall structure, such as a tower, with
a powerful source of light on top; located on a sea-
coast or other water channel to provide guidance
for mariners at sea. Lighthouses were important
facilities in establishing seafaring commerce and
continued to be influential until the latter part of
the 20th century, when they were largely replaced
by electronic guidance systems.

lighting l.The various processes, systems,
forms, and/or equipment used to provide light
and illumination. 2. See accent lighting, cove
lighting, etc.

lighting batten A batten, 9 for lighting equip-
ment.

lighting booth A booth, usually with a view of
the stage, where the light-control console is
located.

lighting cost, cost of light In lamp evalua-
tion, the cost of light rather than total system
cost; commonly expressed as the cost per million
lumen-hours; depends on lamp cost, operating
energy cost, and lamp replacement cost.

lighting fitting British term for luminaire.

lighting fixture An electrical component used
to hold a lamp, fluorescent light, or the like; often
includes a shade or light reflector; may be entirely
functional in appearance or decorative in design.

lighting instrument A luminaire, esp. one
that is portable and can be aimed, focused, or
adjusted, as in theater lighting.

lighting outlet An electrical outlet intended
for the direct connection of a lampholder, a
lighting fixture, or a pendant cord which termi-
nates in a lampholder.

lighting panel l.An electric panel contain-
ing fuses or circuit breakers used to protect
branch circuits serving lighting fixtures. 2. A
panel for switching or controlling lights and
lighting circuits.

588

light pipe

lighting panel

lighting panelboard A panelboard which has
10% or more of its overcurrent devices rated at
no more than 30 amperes.

lighting track A special type of surface race-
way with preassembled electrical conductors in
an open U-track; designed so that a lighting fix-
ture (equipped with a special connector) may be
inserted into the open U-track; the fixture is
then twisted 90° to make contact with the con-
ductors on the track.

lighting unit A luminaire; esp. a portable
luminaire.

light loss factor A factor used in calculating the
illumination provided by a lighting system after a
given period of time and under given conditions;
includes the effects of temperature, voltage, bal-
last variations, dirt on luminaire surfaces, dirt on
the room surfaces, maintenance procedures, and
atmospheric conditions. There are two categories:
losses which can be recovered by replacing old
lamps or cleaning surfaces, and nonrecoverable
losses, such as those due to component deteriora-
tion or uncontrollable voltage drops.

lightly coated electrode See coated electrode.

lightness The whiteness of a painted surface as
measured by the amount of light reflected from it.

lightning arrester A device which is connected
in an electric wiring system (usually between a
line voltage terminal and ground) to protect the
wiring system from damage from lightning or any
other abnormally high surge of voltage.

lightning arrester

lightning conductor, lightning rod A

metallic cable or rod, running from the highest
point on the roof of a building (and insulated
from it) to the ground; protects the building,
should lightning strike, by providing a direct
path to ground.

* CONDUCTOR

*- GROUND
lightning conductor

lightning rod A rod-like electrical conductor
attached to the highest exterior point of a build-
ing; provides a direct electrical path to the
ground if lightning strikes the building, furnish-
ing protection against lightning-induced dam-
age; invented in 1752 by Benjamin Franklin,
who established that lightning is an electrical
phenomenon.

lightning shake Separation between annual
rings of wood, caused by lightning damage to the
tree cambium during growth.

light output The total rate of flow of light
energy emitted by a luminaire, 1 .

light output ratio The ratio of the light output
of a lighting fixture to the total light output of
the individual lamp it houses.

light pipe Same as lighting batten.

589

lightproof blind

lightproof blind A vertically operable light-
proof shade which travels in guides that are fixed
to the window jambs; when in the down posi-
tion, the window is eliminated as a natural
source of light.

light reflectance See reflectance.

light-reflective glass See reflective glass.

light resistance The ability of a material, such
as a plastic, to resist fading after exposure to sun-
light or ultraviolet light.

light source A See standard source A.

light source B See standard source B.

light source C See standard source C.

light tormentor A vertical pipe at either side
of a theater or auditorium proscenium, used for
mounting lighting units.

light transmittance See transmittance.

lightweight aggregate Aggregate of low-bulk
specific gravity, such as expanded or sintered
clay, foamed slag, fly ash, exfoliated vermiculite;
used as an ingredient in lightweight concrete.

lightweight concrete Concrete of substan-
tially lower density than that made from gravel
or crushed stone; usually made with light-
weight aggregate or by injecting air or gas into
the mortar.

light 'well A shaft within a building, open to
the outer air at the top, used to admit daylight
and air through windows opening onto the shaft.

lignin l.An organic substance in wood that,
with celluloses, forms the principal constituent
of wood tissue. 2. A crystalline product recov-
ered from paper pulp; used in the manufacture of
plastics, as a binder in wood chipboard, and for
anticorrosive coatings.

lignum In ancient Roman construction, a beam
or timber in a building, generally applied to the
tie beam of a roof.

limba A straight-grained, fine-textured wood of
the limba tree; esp. used for paneling.

lime A white or grayish-white caustic substance,
calcium oxide, usually obtained by heating lime-
stone or marble at a high temperature; used
chiefly in plasters, mortars, and cements. In the
past, in many areas along the seacoast where
limestone was scarce, seashells were heated to
obtain lime. See also hydrated lime, hydraulic
lime, mortar, shell lime, slaked lime.

lime-and-cement mortar Hydrated lime,
lime putty, or slaked lime mixed with portland
cement and sand; forms a cement mortar used
in masonry and in portland cement plaster
(stucco).

lime burning The calcining (heating) of lime.

lime concrete A concrete made from a mixture
of lime, sand, and gravel, widely used before the
lime matrix was replaced by portland cement.

limed rosin Rosin reacted with lime; used as a
binder in paints.

lime glass A common form of glass; contains a
high proportion of lime.

lime mortar A mortar made by mixing lime
putty and sand; now little used because of its
slow hardening.

lime paste Lime soaked with water to form a
putty.

lime plaster A base-coat plaster consisting of
lime and aggregate.

lime putty, plasterer's putty A hydrated
lime which has been slaked with sufficient water
to form a thick paste; used in plastering.

lime rock A natural, consolidated or partially
consolidated form of limestone; mostly of cal-
cium carbonate, but containing some silica.

limestone Rock of sedimentary origin com-
posed principally of calcite or dolomite or both;
used as building stone or crushed-stone aggre-
gate or burnt to produce lime.

limestone marble A re-crystallized limestone,
including commercial marble; capable of taking
a high polish.

limestone tuff A soft, easy-to-cut stone that
cannot be polished; composed mainly of car-
bonic material.

lime-tallow wash A mixture of lime and
water with tallow; used on roofs, walls, and other
external surfaces.

limewash A mixture of lime and water; used to
coat internal and external surfaces; a whitewash.

limewood See basswood.

limit control A safety device on a boiler, refrig-
erator, or air-conditioning system which shuts
off the system and actuates alarms when unsafe
conditions are detected. Also see limit switch.

limit design Structural design based on any
chosen limit of usefulness, such as a plastic limit,

590

lined eaves

stability limit, elastic limit, fatigue limit, or
deformation limit.

limited combustible material A building
construction material which does not comply
with the NFPA definition of noncombustible
material. The materials in this classification
must not exceed a potential heat value of 3500
Btu per pound (8141 kj/kg); in addition, they
must comply with at least at least one other
applicable requirements of the applicable NFPA
standard.

limiter A special-purpose fuse (usually of high
current-interrupting rating) designed to protect
an electrical circuit or equipment from the
effects of high available short-circuit current by
limiting the amount of current permitted to flow
through it.

limiting height 1. The maximum height of a
building permitted by code. 2. The maximum
height of a partition or wall that can be designed
and constructed without exceeding the allowable
deflection for a given design load.

limit of proportionality See proportional
limit.

limit state A condition beyond which a struc-
ture is unfit to perform its intended function.

limit switch An electric switch, operated by a
power-driven machine or by the movement of
the car which it drives, which alters or controls
the electric circuit associated with the machine,
e.g., a switch which slows down and stops an ele-
vator car or dumbwaiter car automatically at or
near the top or bottom terminal landing; oper-
ates independently of the device which nor-
mally controls movement of the car.

limonite A naturally occurring mineral which
is used in high-density concrete because of its
high density and water content, making it effec-
tive in radiation shielding.

LIN On drawings, abbr. for "linear."

linden See basswood.

line l.A system of cables and/or wires (along
with poles to support them) used for the general
distribution of electricity. 2. A flexible cable,
chain, rope, or the like.

linear diffuser, slot diffuser, strip diffuser
An air outlet where the ratio of length to width of
the outlet usually exceeds 10:1; the width of the
outlet usually is not greater than 4 in. (10 cm).

linear dimension A dimension measured along
a straight line.

linear light source A light source whose
dimension along a line is significantly greater
than its other dimensions as, for example, a line
of fluorescent lamps.

linear packer An automatic refuse compactor
similar to a carousel packer, but the bags, con-
tained on a linear carriage, move along a straight
line; especially suitable for use in very narrow
locations.

Compactor 111)

linear packer

linear plan A house plan that is either one
room wide and two or more rooms deep, or one
room deep and two or more rooms wide.

linear prestressing Prestressing as applied to
linear structural members, such as reinforced
concrete beams or columns.

linear-type heat detector In a fire detection
system, a heat sensor that can be activated any-
where along its length; employs a heat-sensitive
cable whose electrical conductivity depends
significantly on temperature. (See illustration
p. 592.)

lined eaves A board that lines the underside of a
roof which projects beyond an exterior wall.

591

line drilling

, Center conductor

Ceramic thermistor

y Stainless steel
Jf tubing

linear-type heat detector

line drilling In rock excavation by blasting,
drilling a series of closely spaced holes, about
4 in. (10 cm) apart, at the perimeter of the cut,
so as to break the rock along a line.

line drop The decrease in voltage in the con-
ductors of an electric circuit resulting from their
resistance.

line level A special spirit level used in checking
the floor of an excavation, in laying pipe, and for
similar work; each end of the level has a hook,
permitting it to be hooked over a horizontally
stretched line; is especially light and short.

line level

linenfold, linen pattern, linen scroll A

form of carved paneling representing a symmet-
rical fold or scroll of linen.

line of collimation See line of sight.

line of levels In surveying, a continuous series
of measured differences of elevation.

line of pressure A line indicating the points
of pressure between the voussoirs of an arch or
buttress.

linenfold

line of sight, line of collimation The line
extending from an instrument along which dis-
tant objects are seen, when viewed with the tele-
scope or other sighting device. Also see sight line.

line of travel See walking line.

line pin In bricklaying, a steel pin used as a
support for the line by which a bricklayer aligns
his work.

line pipe A welded or seamless pipe, available
with the ends plain, beveled, grooved, ex-
panded, flanged, or threaded; principally used to
convey gas, oil, or water.

liner l.In fabrication of stone veneer (princi-
pally marble), stone bonded to the back of the
thin facing sheets to add strength, rigidity, bear-
ing surface, or depth of joint. 2. A tool used by
painters. 3. A sleeve piece used in plumbing.
4. Same as jamb lining.

liner plate A prefabricated plate of stamped
steel; has corrugations to provide stiffness; pro-
vided with flanges so that similar units can be
bolted together to form a support system for a
tunnel, shaft, or pit.

line voltage The voltage provided by an elec-
tric power line at the point of use.

LIN FT On drawings, abbr. for "linear foot."

lining 1 . Material which covers any interior sur-
face, such as framework around a door or win-
dow, or boarding which covers the interior
surfaces of a building. 2. Same as flue lining.

lining out Marking timber for cutting.

lining paper l.A paper, usually waterproof,
fastened to the studding of frame buildings

592

lip strike

before nailing on the weatherboarding; used

under slates and shingles in roofing. 2. An

undercoat paper, applied to a surface as a base for

a decorative wallpaper.
lining plate In sheet-metal roofing, a metal

strip which is attached to the eaves to secure the

lower edge of the roofing sheets.
lining tool A slanting-edged tool used by

painters in drawing lines.
link dormer A dormer which joins one part

of a roof to another, or one which houses a

chimney.

link dormer

linked switch Two or more electric switches
which are mechanically connected by operating
arms or levers, so as to operate at the same time
or in a desired sequence.

link fuse An exposed fuse which is mounted on
electrically insulated supports.

linoleum A resilient floor-covering material
made by combining an oxidized linseed-oil binder
and ground cork and bonding to a burlap or can-
vas backing; relatively low in cost; has poor stain
resistance and low abrasion and dent resistance.

linseed oil A commonly used drying oil in
paints and varnishes. Also see raw linseed oil.

lintel A horizontal structural member (such as a
beam) over an opening which carries the weight
of the wall above it; usually of steel, stone, or
wood. Also see door lintel, eyebrow lintel, fire-
place lintel, splayed lintel, through lintel.

lintel block, U-block A concrete masonry
unit having a single core with an open end; usu-
ally placed with its open end upright; such
blocks form a continuous beam when filled with
grout and proper reinforcement.

steel lintel

i n~

JL^:-.v:. : :v4

-1

stone lintel

lintel course In stone masonry, a course set at
the level of a lintel, commonly differentiated
from the wall by its greater projection, its fin-
ish, or its thickness, which often matches that
of the lintel.

lintol Same as lintel.

lip 1. A rounded overhanging edge or member.
2. See lip strike.

lip block In timberwork supporting an excava-
tion, a short timber which is fixed to the top of a
strut and which projects over a wale.

lip molding A molding resembling an over-
hanging lip; commonly used as a buttress cap or
base molding in the Perpendicular style.

lippage A ragged appearance that occurs when
the upper edges of adjacent stones are not laid at
the same level.

lipping A strip of wood that covers the edge of a
built-up door so that the joints between the core
and veneer are not visible.

lip strike The projection from the side of a
strike plate which the bolt of a lock strikes first,
when a door is closed; projects out from the side
of the strike plate to protect the frame. (See illus-
tration p. 594.)

593

lip union

□ 1

lip strike

lip union A pipe union having a lip to prevent
the gasket from being squeezed into the pipe.

liquefaction 1 . The sudden, large decrease of
shearing resistance of a cohesionless soil
caused by a collapse of the soil structure, pro-
duced by shock or small shear strains, associ-
ated with a sudden but temporary increase of
pore water pressures. 2. The process of trans-
forming a soil from a solid state to a liquid
state, usually as a result of increased pore pres-
sure and reduced shearing resistance. For
example, an action in which a soil deposit
(e.g., loose sand) loses its shear resistance tem-
porarily and takes on the character of a liquid;
such action, for example, may occur during an
earthquake.

liquid-ash removal system A system for the
removal of molten ash (continuously or inter-
mittently, as desired) from the bottom of a fur-
nace, by a piping arrangement operated by
compressed air.

liquid asphaltic material An asphaltic prod-
uct so soft that its consistency cannot be measured
at normal temperature by a penetration, 2 test.

liquidated damages A sum specified in a con-
tract whereby damages in the event of breach
are to be determined. In a construction contract,

liquidated damages usually are specified as a
fixed sum per day for failure to complete the
work, 1 within a specified time. If set at a level
consistent with a reasonable forecast of actual
harm to the owner, liquidated damage clauses
will be upheld and will preclude use of standards
for computation of damages that would other-
wise be imposed by law. If the amount prescribed
for liquidated damages is unreasonably high, the
provision will be denominated an illegal
"penalty" by the courts and held invalid; in such
case, damages will be determined pursuant to
otherwise applicable rules of law.

liquid chiller l.See compressor- type liquid

chiller. 2. See absorption-type liquid chiller.
liquid drier See soluble drier; drier.

liquid- immersed transformer A trans-
former having its core and coils submerged in an
insulating liquid such as oil.

liquid indicator A device, frequently com-
bined with a strainer, located in the liquid line of
a refrigeration system and having a sight port by
which the liquid flow may be observed for pres-
ence of bubbles.

liquid limit The water content corresponding
to the limit between the liquid and plastic states
of consistency of a soil.

fl^i"

BEFORE TEST AFTER TEST

liquid limit

liquid line A tube or pipe carrying the refrig-
erant liquid from the condenser or receiver of
a refrigeration system to a pressure-reducing
device.

liquid-membrane curing compound A
material, laid down in the form of a liquid,
which acts as a sealant.

liquid petroleum gas See liquified petroleum
gas.

liquid receiver A vessel permanently con-
nected to a system by inlet and outlet pipes for
the storage of (condensed) refrigerant.

liquid roofing A seamless roofing material,
applied in liquid or semiliquid form, to produce a
waterproof membrane.

liquid-volume measurement The measure-
ment of grout according to the total volume of
its liquid and solid constituents.

liquid waste The discharge from any fixture,
appliance, area, or appurtenance which does not
contain fecal matter.

liquified natural gas (LNG) A product of
natural gas essentially consisting of methanes;

594

LL&B

stored under pressure to maintain its liquid state;
used as a fuel for heating and cooking.

liquified petroleum gas (LPG) A petroleum
derivative, primarily butane and propane, stored
under pressure to maintain its liquid state; used as
a fuel for heating and cooking.

L»iron Same as angle iron.

lisena A Romanesque pilaster strip.

listed Equipment, materials, or products included
in a list published by an organization acceptable
to the authority having jurisdiction; the organiza-
tion is concerned with the evaluation and peri-
odic inspection of production of listed items; a
listed item must meet appropriate standards or
must have been tested and found suitable for use
in a specified manner.

listed building Any building designated as
being of historic architectural interest by one of
the many organizations dedicated to the preser-
vation of historic architecture.

listel, list A Met, 1.

listing The sapwood cut from the edge of a
board.

lite Same as light, 2.

liter, litre A metric unit of volume equal to
1/1000 cubic meter; equal to 61.03 cubic inches.

litharge A yellow lead monoxide (a powder of
lead oxide); used as a pigment, as a drier, and as
a catalyst in paints. Also see massicot.

lithic Pertaining to stone.

lithopone A white pigment consisting of zinc
sulfide and barium sulfate, having moderate hid-
ing power; high-strength lithopone contains a
higher percentage of zinc sulfide.

lithostrotum opus In ancient Greece and
Rome, an ornamental pavement made of small,
irregular places of stone, such as mosaic.

litmus An organic chemical indicator of acidity

or alkalinity; is red in color for pH values below

4-5 and blue above 8.3.
litre A series of coats of arms of the pious

founders of certain churches in the Middle Ages

and the Renaissance.

little house An 18th-century euphemism for
an outdoor toilet; a privy.

liturgical choir That part of a choir reserved
for the clergy serving the church.

liturgically sited Said of a church that is laid
out in plan so that the congregation faces toward
Jerusalem.

live 1. Connected to a source of voltage.
2. Said of a room having an unusually small
amount of sound absorption.

live boom A boom on a power that can be
raised or lowered without interrupting the dig-
ging operation.

live edge The edge of a painted surface which
can be blended with fresh paint without having
the lap show.

live»front Descriptive of a piece of electric
equipment which is so constructed that there are
live parts which can be touched from the front of
the assembly.

live knot See intergrown knot.

live load The moving or movable external load
on a structure; includes the weight of furnishings
of a building, of the people, of equipment, etc.,
but does not include wind load.

liveness The acoustical quality of a live room.

live part Any electric component or part which
is designed to operate at a voltage different from
that of the earth.

livering The thickening of paint or varnish to
an unusable rubbery consistency.

live room A room characterized by an unusu-
ally small amount of sound absorption.

live steam Steam that has not as yet given up
any of its energy and has not yet condensed, e.g.,
steam emerging from a boiler.

living area See dwelling unit.

living hall, living stair hall A large room at
the entry to a house, especially in an elegant
home; frequently contains an imposing staircase,
fireplace, and seating area; often, simply called
the hall; also see entrance hall.

living room A space in a dwelling for social use
of the residents.

living unit A dwelling or portion thereof, pro-
viding complete living facilities for one family,
including permanent provisions for living, sleep-
ing, eating, cooking, and sanitation.

LL On drawings, abbr. for live load.

L&L Abbr. for "latch and lock."

LL&B Abbr. for "latch, lock, and bolt."

595

lm Abbr. for lumen.

LM On drawings, abbr. for lime mortar.

LNG Abbr. for liquified natural gas.

lng, Lng Abbr. for "lining."

LOA On drawings, abbr. for "length overall."

load 1. A force, or system of forces, carried by a
structure, or a part of the structure. 2. Any
device or piece of electric equipment that
receives electric power. 3. The power delivered
to such a device or piece of equipment. 4. The
amount of heat per unit time imposed on a
refrigeration system; the required rate of heat
removal.

load balancing The pre-stressing of a beam or
slab so that it is subject to zero bending move-
ment under its service load.

load-bearing partition A partition capable of
supporting a load in addition to its own weight.

load-bearing tile Tile, used in masonry walls,
which carries superimposed loads.

load-bearing wall A wall capable of supporting
an imposed load in addition to its own weight.

load-carrying band A flat piece of metal
which is welded to a side or end of a grating
panel, used in a cutout to transfer the load from
unsupported to supported bearing bars.

load-deflection curve A graph in which
increasing flexural loads on a beam are plotted
along the vertical axis, and deflections resulting
from these loads are plotted along the horizontal
axis. See flexure.

loader A self-powered machine equipped with a
front-mounted bucket and lift arms for pushing
and raising a load of earth or other construction
materials; usually mounted on wheels or crawler-
track undercarriage.

loade

load factor 1. In structural design, the factor by
which a working load is multiplied to determine
the design ultimate load. 2. In air conditioning,
the ratio of the average load on a system to the
maximum load capacity. 3. In plumbing, the per-
centage of the total flow rate (expressed in fix-
ture units) which is likely to occur at any point in
the drainage system; represents the ratio of the
probable load to the potential load.

load factor design A method of structural
design based on the use of a given working load
times a multiple; also see limit design.

load-indicating bolt A special type of high-
strength bolt having a small projection which
compresses as the bolt is tightened; the amount of
projection can be measured with a feeler gauge,
thereby acting as a measure of the bolt tension.

loading cycles In structural design, the number
of repetitions of load assumed to act on a struc-
ture during its lifetime; used as a criterion in
determining the fatigue strength of the structure.

loading dock See loading platform, 1.

loading dock leveler An adjustable-level
platform or ramp which facilitates the handling
of goods or materials to or from trucks, at a load-
ing dock or at pavement level.

loading dock seal A resilient pad around the
door of a loading dock to provide a tight seal
between the door and a truck which has backed
into the loading dock.

loading dock shelter A waterproof canopy
which extends out from a building to provide
weather protection between loading dock doors
and the opening of a truck.

loading door A theater stage door through
which scenery, properties, and other equipment
are moved.

loading gallery A narrow gallery above the fly
floor (fly gallery) in the stagehouse of a theater.

loading hopper A hopper, 1 in which con-
crete or other free -flowing material is placed for
loading by gravity into buggies, etc.

loading platform, loading dock 1. An ele-
vated platform at the shipping or delivery door
of a building or adjacent to the stage of a theater;
usually at the same height as the floor of a motor
truck or railroad car to facilitate loading or
unloading. 2. A platform on a theater stage for
storing counterweights, 2.

596

locknut

loading ramp A device or facility (hinged,
mechanical or hydraulic) to provide for differ-
ences in the heights or to span gaps between a
loading surface and a carrier.

loading shovel Same as loader.

load-transfer assembly A unit which is
designed to link or support dowel bars in the
desired position during concreting operations.

loam In building construction, a mixture com-
posed chiefly of moistened clay, sand, and silt,
or some mixture including these ingredients.
Once used as a mortar when combined with
lime, or used as a plaster with the addition of
chopped straw.

lobby A space at the entrance to a building,
theater, etc.

lobe A segment of a circle in tracery; a foil.

lobed arch A cusped arch.

local buckling The buckling of a compression
element which may precipitate the failure of the
whole structural member.

local lighting Lighting which illuminates a rel-
atively small area without illuminating the gen-
eral surroundings significantly.

local vent, local ventilating pipe A pipe
on the fixture side of a trap through which
vapor or foul air is removed from the room or
fixture.

local vent stack A vertical pipe, to which
connections are made from the fixture side of
traps, and through which vapor and/or foul air
may be removed from the fixture.

location block Same as setting block.

location plan Same as site plan.

location survey The establishment on the
ground of points and lines in positions which
have been determined previously by computa-
tion or by graphical methods, or by a descrip-
tion obtained from data supplied by documents
of record, such as deeds, maps, or other sources.

lodged floor A floor that is held in place by its
own weight.

lock A mechanical device that secures a door,
gate, cabinet, or the like; may be operated by a
key or by a dead bolt. The earliest door locks
had a hardwood casing with working parts fab-
ricated of metal; later, these were replaced by
all-metal locks. A further significant advance

in lock design was the invention of the pin-
tumbler cylinder lock in 1848. Also see box
lock, case lock, door lock, rim lock, stock lock.

lock backset The distance from the edge of a
door to the center line of the lock cylinder.

lockband A course of bondstones.

lock bevel The direction in which a latch bolt
is inclined.

lock block In a hollow-core flush door, a block
of wood (the thickness of the door stile) to
which the lock is fitted.

lock clip A flexible metal part which is
attached to the inside of a door face to position
a mortise lock.

lock corner A corner (as of a drawer) which is
secured by an interlocking construction, such as
a dovetail.

lock edge See leading edge.

locker A lockable cupboard for storage of per-
sonal property for protection from theft.

locker plant A public facility containing lock-
able cupboards rented for cold or frozen storage
of privately owned food.

lock face The exposed surface of a mortise lock
which shows in the edge of a door after installa-
tion of a lock.

lock faceplate Same as lock front.

lock front, Brit, forend On a door lock or
latch, the plate through which the latching or
locking bolt (or bolts) projects.

lock front bevel The angle of a lock front
when not at right angle to the lock case, allow-
ing the front to be applied flush with the edge of
a beveled door.

locking device Any device used to secure a
member, unit, or assembly in position, e.g., to hold
a cross brace in scaffolding to the frame or panel.

locking stile See lock stile.

lock jamb See strike jamb.

lock joint See lock seam.

lock keeper The box on a doorjamb into
which the bolt of a lock protrudes.

lock miter A miter joint having interlocking
edges. (See illustration p . 598.)

locknut 1 . A nut which is designed so that it
will not come loose, locking in place when tight-
ened. 2. A supplementary nut, screwed down on
another nut to prevent it from shaking loose.

597

lock plate

'tJL

lock miter

lock plate l.Same as strike plate. 2. Same as

box strike plate.
lock rail An intermediate horizontal structural

member of a door, between the vertical stiles, at

the height of the lock.

lock seam door A door which has its face
sheets secured in place by an exposed mechanical
interlock seam on each of its two vertical edges.

lockset A complete lock system including the
basic locking mechanism and all the accessories,
such as knobs, escutcheons, plates, etc.

lockshield valve Same as key valve.

lockspit A small cut with a spade, or a small
open trench, to mark a line of work, as fencing
or the like.

lock stile, closing stile, locking stile, strik-
ing stile The vertical structural member of a
door (or a casement sash) which closes against
the jamb (or mullion) of the surrounding frame;
the side away from the hinges.

lock rail

lock stile

lock reinforcement A reinforcing plate at-
tached inside of the lock edge or lock stile of a
door to receive a lock.

lock reinforcing unit A metal device used in
a metal door to contain and support a lock.

locksaw A compass saw with a tapering flexible
blade; used for cutting the seats for locks in doors.

lock seam, lock joint A joint or seam in
sheet-metal roofing; the two edges are bent over
in the form of hooks which are inserted in each
other; then they are dressed down to form a
seam.

lock strike Same as strike plate.

lock- strip gasket, structural gasket A gas-
ket in which the sealing pressure is produced by
forcing a keyed lock strip into a groove in one
face of the gasket.

lockup A building or room for the temporary
detention of prisoners by police.

loculus In ancient tombs, a recess for a sarcoph-
agus or cinerary urn.

locust, black locust, red locust Wood of
the locust tree; coarse-grained, strong, hard,

598

log house

decay-resistant, and durable; used in construc-
tion, esp. for posts.

locutorium Same as locutory.

locutory A place for conversation; esp. the par-
lor of a monastic establishment.

lodge l.A small house in a park, forest, or
domain; a temporary habitation; a hut. 2. The
meeting place of a fraternal organization. 3. A
porter's or gatekeeper's house at the entrance to
the grounds of an estate.

lodging chamber Same as bedroom.

lodging house A building containing rooms
used or rented for sleeping purposes by two or
more paying guests; the minimum and maximum
numbers of rooms may be specified by the
applicable local code.

loess A uniform wind-deposited accumula-
tion of silty material having an open structure
and relatively high cohesion due to cementa-
tion of clay or calcium-like material at grain
contacts.

loft 1. Unceiled space beneath a roof, often used
for storage. Also see attic, garret. 2. Upper space
in a barn, e.g., cockloft, hayloft. 3. Upper space in
a church or concert hall, e.g., choir loft, organ
loft. Also see rood loft. 4. Unpartitioned space in
a loft building. 5. In a theater stagehouse, the
space between the top of the proscenium and the
grid.

loft building A building, containing open,
unpartitioned floor space, used for commercial
or industrial purposes.

loft ladder A disappearing stair.

log cabin A general term often applied to
two different types of dwellings, both of which
are constructed of logs. A log cabin is con-
structed of straight, relatively smooth, round
logs stripped of their bark and laid horizon-
tally, one above the other, to form a structure.
In contrast, a log house is constructed of logs
that are hewn to form square timbers before
they are assembled as a structure. The con-
struction of these two types of dwellings dif-
fers with regard to the tools, skill, and time
required for their construction. In both, the
logs are notched or otherwise fastened
together to prevent their spreading at the cor-
ners and to provide rigidity and strength, but
in a log cabin the logs protrude beyond the

log cabin

joints; in the log house, the square-hewn tim-
bers do not protrude beyond the joints. Log
cabin construction requires only an ax, a min-
imum of skill, and a minimum of construction
time. The walls are usually waterproofed by an
infilling between the cracks, such as clay. Typ-
ically, both types have a pitched roof. The ear-
liest log cabins in America usually consisted of
a single room; they usually had a battened
door, and where brick or stone was scarce, a
clay-and-sticks chimney. Compare with log
house; also see dogtrot cabin, double-pen
cabin, notch, planking, saddlebag cabin, verti-
cal log cabin.

log-cabin siding An exterior wood siding,
used on a small structure, which gives it the
appearance of having been constructed of logs.

loge 1. A box in a theater. 2. The front section
of a mezzanine or lowest balcony in a theater;
usually separated by an aisle and/or railing from
the section behind it.

logeion, logeum The raised platform for the
actors in the Hellenistic theater, corresponding
to the modern stage.

loggia An arcaded or colonnaded porch or
gallery attached to or contained within a larger
structure; usually located in a prominent part
of the building; open on at least one side to
provide a protected outdoor sitting area, some-
times contains an upper story. (See illustration
p. 600.)

log house A house constructed of squared tim-
bers that have been hewn from round logs, thus
requiring an adze and/or other tools to shape
them; the timbers are laid horizontally and
notched or otherwise fastened to prevent their
spreading at the corners and to provide rigidity

599

log notch

° 6Gia n j

■ » " wni n ii i wi u \ vr wz,i

loggia

and strength, and do not protrude at the corners
as they do in a log cabin. The house usually has
a shingled, pitched roof; often a chimney on a
gable-end wall. Compare with log cabin, which
is much easier to build.

log notch See notch.

lolly column Same as Lally column.

Lombard architecture North Italian pre-
Romanesque architecture in the 7th and 8th

cent., during the rule of the Lombards, based
on Early Christian and Roman forms.

Lombard style l.A synonym occasionally
used for the Italianate style. 2. A term once
applied to Romanesque Revival, now usually
called Richardsonian Romanesque style.

London stock brick Originally, handmade
bricks produced in the vicinity of London,
made on a "stock," i.e., a block of wood that
locates the mold on the mold table; now
machine-made brick of a coarse-textured
yellow.

long-and-short work In rubble masonry,
quoins which are placed alternately horizontally
and vertically.

long-and-short work

t^0\.

Lombard architecture

long column A concrete column whose load
capacity must be reduced, according to code
requirements, because of its slenderness.

long float A float so long that two men are
required to handle it.

long gallery A gallery in the upper stories of
an Elizabethan or Jacobean manor house; often
used as a promenade or family room.

long grip The grip of a bolt or rivet which is
longer than five times its diameter.

long header A header which runs the full
depth of a thick wall.

600

loop window

longhouse 1 . A multifamily dwelling usually
having a rectangular plan divided by a central
aisle along the length. 2. A 20th-century term
for a building that once provided both the
domestic quarters for a family and housing for
animals.

longitudinal axis An axis along the length-
wise direction of the figure or body, usually pass-
ing through its center of gravity.

longitudinal bar A steel reinforcing bar used
in longitudinal reinforcement.

longitudinal bond A masonry bond in which
occasional courses are laid with all stretchers;
sometimes used in thick walls.

longitudinal bracing Bracing extending length-
wise of the structure, or parallel to its center line.

longitudinal joint Any joint which fastens
two pieces along their length.

longitudinal reinforcement Steel rein-
forcement, 1 for concrete which is essentially
parallel to the horizontal concrete surface, or to
the long axis of a concrete member.

longitudinal section In graphic representa-
tion, a section, 1 taken along the longest axis.

longitudinal shear A shear, 1 which is paral-
lel to the longest axis of a member.

long-life lamp Any lamp type having a design
life longer than the conventionally set value for
its general class; an incandescent lamp of this
type provides lower luminous output than a
standard lamp of the same wattage.

long nipple A nipple having a considerable
unthreaded length.

long nipple

long-oil alkyd An alkyd resin in which over
60% of the solids consist of an oxidizing oil; used
for brushing enamels.

long-oil varnish See long varnish.

long-radius elbow An elbow, 1 having a
radius larger than standard to reduce friction
losses and improve flow characteristics.

long room Primarily in the 17 th and 18th cen-
turies, a room for social gatherings, usually
attached to a tavern.

long screw A pipe nipple usually 6 in. (15 cm)
in length, with one thread much longer than
usual.

long ton The equivalent of 2,240 lb (1,016 kg).

long varnish, long-oil varnish An oleo-
resinous varnish containing 20 to 100 gal oil per
100 lb (2 to 10 liter oil per kg) gum or resin;
more durable, more flexible, less glossy, and
softer than short-oil varnish.

lookout 1 . A rafter or joist at the ridge of a roof
that projects beyond an end wall of a building;
may support the overhanging portion of the roof
or cornice; also called a rafter lookout. 2. An
elevated place or structure that provides a wide
view for observation of the countryside, particu-
larly against marauders.

lookout tower A belvedere.

lookum A small roof or penthouse used to shel-
ter a wall crane, hoisting wheel, or the like.

loom See flexible nonmetallic tubing.

loom house Same as spinning house.

loop 1. A loophole. 2. A circuit vent.

loophole l.See arrow loop. 2. In a fortifica-
tion, one of a number of long, narrow slits in the
walls, usually widening inward to permit small
arms to be fired over a wide angle at an enemy.
3. Same as slit ventilator.

looping in A method of avoiding splices in res-
idential electric wiring by carrying the conduc-
tor or cable to and from the outlet to be
supplied.

loop vent 1 . A vent arrangement for a group
of plumbing fixtures; consists of a vent pipe
which is connected to the waste or soil branch
immediately before the first fixture of the
group and immediately before the last fixture
of the group; the two connections are then
"looped" together and connected to the vent
stack. 2. The same as a circuit vent except that
it loops back and connects with a stack vent
extension of the soil stack instead of a separate
vent stack.

loop window A long, narrow, vertical open-
ing, usually widening inward, cut in a medieval
wall, parapet, or fortification for use by archers;
an arrowloop. (See illustration p. 602.)

601

loose-box

(t>

loop windows

loose-box See box stall.

loose-butt hinge Same as loose-joint hinge.

loose core See strip core.

loose cubic yard (or meter) A unit to
express the volume of loose material.

loose-fill insulation Thermal insulation in
the form of granules, nodules, fibers, powder,
flakes, or shreds; may be hand-packed, pneu-
matically placed, or poured into cavities or over
supporting membranes. Also see granular-fill
insulation.

loose grid In a theater stagehouse, a counter-
weight system using rope ties at the pinrail,
instead of fixed counterweights.

loose insulation Same as loose-fill insulation.

loose-joint hinge, heave-off hinge, lift-off
hinge, loose-joint butt A door hinge hav-
ing two knuckles, one of which has a vertical pin
(at its center) that fits in a corresponding hole in
the other; by lifting the door up, off the vertical
pin, the door may be removed without unscrew-
ing the hinges.

loose-key faucet A faucet that can be opened
only with a tool or special handle so as to pre-
vent its unauthorized use.

loose knot A knot in wood which is not firmly
in place and may fall out.

loose-laid membrane A ballasted roofing
membrane that is only attached to the sub-
strate along the edges and at penetrations
through the roof.

loose lintel A lintel that is not attached to
another structural member but is merely placed
across an opening in a wall during construction
to support the weight of the wall above.

loose material Soil or rock in a blasted, bro-
ken, or loose state.

loose molding A removable wood glazing bead.

loose-pin hinge A hinge having a removable
pin which permits its two parts to be separated.

£5

c *

©>

loose-pin hinge

loose side, slack side The side of knife-cut
wood veneer, next to the knife, which has
numerous small checks as a result of the cutting
operation.

loose stop A nailed-on or planted stop bead; a
planted stop.

loose tongue l.Same as cross tongue. 2. A
spline in a spline joint.

loose-tongue miter A mitered joint having
matching grooves into which a common key or
tongue is fitted to align or strengthen the joint.

loricula Same as squint, 1.

lorymer A larmier.

loss of gloss A paint defect in which a dried
film of paint loses gloss, usually over a period of
several weeks.

602

Louis XV

loss of prestress In prestressed concrete, the

reduction of the prestressing force which results
from the combined effects of creep in the steel
and creep and shrinkage of the concrete; nor-
mally does not include friction losses but may
include the effect of elastic deformation of the
concrete.

loss of use insurance Insurance protecting

against financial loss during the time required to

repair or replace property damaged or destroyed

by an insured peril.
lost ground Soil which runs from outside to

within an excavation, as around or through

sheeting, or as a boil on the bottom.
lost-head nail A thin nail having a head only

slightly larger than the diameter of the nail

itself; usually nailed below the surface of the

wood.
lot A parcel of land that is described on a

recorded plat or by a survey.
lot depth The distance from the front of a lot to

the extreme rear line of the lot.
lot front The boundary line of a lot that abuts a

street, or, if it abuts more than one street, then

the street designated by the owner.
lotiform Having the shape of a lotus bud

or flower, as used in some Egyptian column

capitals.

lot line The legally defined boundary or limit of

a parcel of land.
lot»line wall A wall adjoining and parallel to

the lot line, used only by the party upon whose

lot the wall is located.
lotus capital In ancient Egyptian architecture,

a capital having the shape of a lotus bud.

lotus column A column whose capital has
the shape of a stylized lotus; see Egyptian
Revival.

loudness The intensive attribute of an audi-
tory sensation, in terms of which sounds may
be rank-ordered on a scale extending from
soft to loud; depends primarily on sound pres-
sure, but also on the frequency and wave form
of the sound stimulus; expressed in units
called sones; 2 sones is just twice as loud as 1
sone.

loudness level Of a sound, the sound-pressure
level of an equally loud 1,000-Hz pure tone,
expressed in units called phons.

loudspeaker An electroacoustic device, used
to radiate acoustic power in air, the acoustic
waveform of the reproduced sound being
essentially equivalent to that of the electrical
input.

Louis XIV, Louis Quatorze style The
style of the high Classical period in France
under the rule of Louis XIV (1643-1715) in
architecture, decoration, and furniture, culmi-
nating in the building of Versailles. (See illustra-
tion p. 604.)

Louis XV, Louis Quinze style The Classi-
cal and Rococo style in France under the rule of

603

Louis XVI

Louis XIV style: central compartment, northern facade, Louvre

Louis XIV style: overdoor panel

Louis XV style: Pavilion, Hotel Soubise, Paris (c. 1730)
604

Louis XV (1715-1774) in architecture, decora-
tion, and furniture.

Louis XVI, Louis Seize style The later
Rococo and classicist phase of the 18th century
in France under the rule of Louis XVI
(1774-1792), terminated by the French Revolu-
tion.

Louisiana Vernacular architecture See
French Vernacular architecture, Cajun cottage,
Creole house.

lounge An informal sitting room, esp. in a
hotel, theater, or institutional building.

louver l.An assembly of sloping, overlapping
blades or slats; may be fixed or adjustable;
designed to admit air and/or light in varying
degrees and to exclude rain and snow; esp. used in
doors, windows, and the intake and discharge of
mechanical ventilation systems. 2. A dome or
turret rising from the roof of the hall of a medieval
English residence, originally open at the sides to

louver door

i-mimmmt w n wtwt w ffiaifwrn '

i
li

■ I!

Ill

Louis XVI style

allow the escape of smoke from the open hearth
below; also called a lantern. 3. In side openings of
a belfry, one of many sloping overlapping slats
with a fixed open-space between them; sound
produced by bells in the belfry is transmitted
through these openings to the surrounding area.
(See illustration p. 606.)

louver board One of the narrow boards,
placed at an angle, in a louver or louver window;
also called a luffer board.

louver door A door containing a louver, usu-
ally with horizontal blades, providing for the
passage of air while the door is closed. (See illus-
tration p. 606.)

Louis XVI style

605

louvered ceiling

ss\\

louver door

louvered ceiling A ceiling system consisting
of multicellular louvers which shield the light
sources mounted above it.

louvered shutter See shutter.

louver shielding angle The angle between
the horizontal plane of a louver grid and the
plane beyond which the louver conceals all
objects above it.

louver-type damper A damper, 1 having
multiple blades which are mechanically linked
so that they open or close simultaneously.

louver window l.A window having louvers
which fill all or part of the opening instead of glass.
2. An open window in the tower of a church.

louvre Same as louver.

low-alkali cement A portland cement con-
taining a relatively small amount of sodium or
potassium or both.

low-alloy steel Steel having an alloy content
of less than 8%.

louver window

low bid A bid stating the lowest bid price,
including selected alternates, and complying
with all bidding requirements.

lowboy A type of trailer for hauling construc-
tion equipment, with reduced ground clearance
that facilitates loading of machinery without an
auxiliary ramp.

low-carbon steel Steel having a carbon con-
tent less than 0.20%.

low-density concrete Concrete whose oven-
dry unit weight of less than 50 pounds per cubic
foot (800 kg/m 3 ).

low-emissivity glass, low-e glass l.A glass
that has a special thin-film metallic or oxide
coating which allows short-wavelength energy
of the sun to be transmitted into a building, but
which prevents long-wavelength energy of the
heating systems within the building from escap-
ing to the exterior; thereby conserves heat energy.
2. Same as reflective glass.

lower lateral bracing Same as bottom lateral
bracing.

lowest responsible bidder, lowest quali-
fied bidder The bidder who submits the
lowest bona fide bid and is considered to
be fully responsible and qualified to perform
the work, 1 for which the bid is submitted. In
the case of private construction contracts, the
decision as to the bidder's responsibility and
qualification usually is made by the owner and
the architect. In public contracts, a decision
disqualifying a low bidder may have to be made
on a reasonable basis rather than an arbitrary
one.

lowest responsive bid The lowest bid which
is responsive to and complies with the bidding
requirements.

lowest tender Same as lowest responsive bid.

606

LPG

low-hazard contents Building contents hav-
ing such low combustibility that no self-propa-
gating fire therein can occur.

low-heat cement, type IV cement A

cement in which there is only limited genera-
tion of heat during setting, achieved by modi-
fying the chemical composition of normal
Portland cement.

low-lift grouting In masonry wall construction
employing hollow concrete blocks, a technique
in which wall sections are built as high as 5 feet
(1.7m); then, the cells of the masonry blocks are
filled with grout.

low-noise lamp An incandescent lamp hav-
ing a special internal construction to minimize
the generation of audible noise, esp. when oper-
ated on certain types of dimmers.

low-pressure boiler According to the
ASME Boiler Code, a boiler whose maximum
safe working gauge pressure for steam service is
15 pounds per square inch.

low-pressure laminate A laminate molded
and cured in the range of pressures from 400 lb
per sq in. (28 kg per sq m) down to and includ-
ing the pressure obtained by the mere contact of
the plies.

low-pressure mercury lamp A mercury-
vapor lamp whose partial pressure during opera-
tion does not exceed 0.001 atmosphere;
fluorescent and germicidal lamps are included in
this category.

low-pressure overlay A thermosetting resin-
impregnated, wear-resistant paper, often with a
decorative wood-grain print which has been
applied, under pressure, at a high temperature to
plywood, fiberboard, particleboard, etc., usually
at a pressure of 150 to 250 lb per sq in. (7.5 to
10.5 kg per sq m).

low-pressure sodium lamp A sodium-vapor
lamp having a relatively low partial pressure;
produces a deep yellow light that is essentially
monochromatic; widely used where the color of
the lighting is not important (as, for example, in
lighted parking lots) because of its high efficacy.

low-pressure steam curing Same as atmo-
spheric steam curing.

low relief Same as bas relief.

low-rise building A building that is usually no
more than five stories high.

low-side window, leper's squint, offertory
window, squint A small low window, usu-
ally on the right side of the chancel, through
which the altar may be seen.

low-silicon bronze See silicon bronze.

low steel A soft steel containing a small
amount of carbon (less than 0.25%).

low-studded Having short studs.

low-temperature recovery The ability of
a sealant to recover its original form at low
temperature when the deforming load is
removed.

low-temperature-water heating system
Same as hot-water heating system.

low-velocity HVAC system A heating, ven-
tilating, and air-conditioning system in which
the velocity of air in the ductwork is relatively
low, thus limiting the noise created by the air-
flow through it.

low voltage According to ANSI/IEEE standards,
a nominal system voltage of 1000 volts or less.

low-voltage lighting control A system of
switches, control transformers, relays, and
auxiliary devices to control a number of light-
ing circuits remotely, from one or more
locations.

low-water alarm In a system in which water is
supplied to a building from a gravity tank, an
alarm indicating that the pump supplying the
tank has not activated at the low- water condition
and that water in the tank is dangerously low.

low-water cutoff A device required by the
ASME Boiler Code on any steam boiler that is
automatically fired; prevents the continued fir-
ing of a boiler that contains insufficient water.

lozenge 1 . A rhomb or, more rarely, a rhom-
boid; usually one of a series. 2. In a double lancet
window, a small light which pierces the space
between the heads of the two lancets. (See illus-
tration p. 608.)

lozenge fret, lozenge molding A type of
diamond fret. (See illustration p. 608.)

lozenge light One of many small diamond-
shaped panes of glass used in leaded lights.

LP On drawings, abbr. for "low pressure."

L&P Abbr. for "lath and plaster."

LPG 1. Abbr. for liquid petroleum gas. 2. Abbr.
for liquified petroleum gas.

607

LP gas

lozenge, 2

lozenge fret

LP gas Same as liquid petroleum gas.

L»plan A plan having the shape of a capital
letter L.

LPS Abbr. for "low-pressure sodium."

LR Abbr. for living room.

LS l.Abbr. for "left side." 2. Abbr. for loud-
speaker.

L»shore A shore having an L-head.

LT On drawings, abbr. for light.

lucarne A small dormer window in a roof
or spire.

lucome window A term once used for a win-
dow in the gable end of a house, usually provid-
ing light for a room in a loft or attic.

lucullite A variety of black marble used in
ancient Roman construction; first brought to
Rome from Assan on the Nile River.

luffer Same as louver.

luffer board Same as louver board.

luffing-boom crane A heavy-duty crane hav-
ing a tower- mounted boom, 2.

lug 1 . In electric wiring, a device for terminating
a wire or cable; the lug is bolted to an electric
terminal. 2. A small projection attached to any

lugs, 1

member or component for use in handling,
assembling, or installing.

lug angle See clip angle.

lug bolt A round bolt to which is welded a flat
iron bar.

lug sill A sill, 3, with its ends extending beyond
the window or door and built into the masonry
at the jambs.

lukovitsa In early Russian architecture, an
onion dome.

lumber Timber sawn or split in the form of
beams, boards, joists, planks, etc., esp. that
which is smaller than heavy timber. Also see
board, 1, dimension lumber, matched boards, and
yard lumber.

lumber core, stave core Wood core consist-
ing of narrow strips of lumber edge-glued
together; usually held in place by veneer which
is glued to both faces with the grain of the
veneer at 90° to that in the core.

lumber grade A classification used by the lum-
ber industry for pieces of lumber: the categories
are standard, structural, and utility.

lumen (lm) The SI unit of luminous flux equal
to the luminous flux received on a unit surface,
all points of which are equidistant from a point
source having a uniform intensity of 1 candela.

lumen maintenance curve See life perfor-
mance curve.

lumen method, flux method A procedure
in lighting design used to determine the number
and types of lamps or luminaires required to pro-
vide a desired average level of illumination on a
work plane; takes into account both direct and
reflected light flux.

lumiline lamp A tubular incandescent lamp
having a lamp base at each end.

luminaire 1. A complete lighting unit consisting
of one or more lamps, together with components

608

luminous transmittance

which are designed to distribute the light, to posi-
tion and protect the lamps, and to connect the
lamps to the electric power supply; also called a
lighting fixture. 2. The above lighting unit with-
out lamps in it. 3. A device that projects light on
the stage of a theater.

luminaire classification l.For indoor lumi-
naires, a classification system based on the per-
centage of flux which is emitted by the
luminaire, above (or below) a horizontal plane
through the center of the luminaire. 2. Flood-
lights: a measure of the beam spread in terms of
beam angle ranges: type I, beam angle 10° to
18°; II, 18° to 29°; III, 29° to 46°; IV, 46° to 70°;
V, 70° to 100°; and VI, above 100°.

luminaire dirt-depreciation factor A
factor (used in illumination calculations)
which relates the initial illumination provided
by a clean, new luminaire to the reduced illu-
mination that it will provide as a result of the
accumulation of dirt on the luminaire at the
time when it is next scheduled for cleaning.

luminaire efficiency The ratio of luminous
flux emitted by a luminaire to total flux emitted
by the lamp or lamps in the luminaire.

luminance The luminous intensity of any
surface in a given direction per unit of pro-
jected area of the surface, as viewed from that
direction; a directional property of luminous
radiation.

luminance contrast The relationship be-
tween the luminance of an object and the lumi-
nance of the immediate background.

luminance factor The ratio of the lumi-
nance of a surface or medium under specified
conditions of incidence, observation, and light
source to the luminance of a lossless, perfectly
diffusing surface or medium under the same
conditions.

luminance meter, brightness meter A

visual instrument or a photoelectric instrument
used to measure luminance.
luminescence The emission of light not
ascribable directly to incandescence.

luminosity The ratio of luminous flux to the
corresponding radiant flux at a particular wave-
length; expressed in lumens per watt.

luminous ceiling A ceiling area-lighting system
comprising a continuous surface of transmitting

material (of a diffusing or light-controlling charac-
ter) with light sources mounted above it.

luminous efficacy The ratio of the total emit-
ted luminous flux, in lumens, to the total elec-
tric power consumption in watts.

luminous efficiency Same as luminous effi-
cacy; also called the luminous coefficient.

luminous energy The time integral of lumi-
nous flux; given by the product of the luminous
flux and the time that the flux is maintained, if
the luminous flux is of constant value; usually
expressed in lumen-hours.

luminous flux The rate-of-flow of radiant
energy emitted by a lamp.

luminous intensity The luminous flux per unit
solid angle in a specific direction from a point
source of light; in practice, an interior source may
be considered a point source if the distance
exceeds 5 to 10 times the maximum source
dimension of the luminaire; in US Customary
units, expressed in candlepower; in SI units,
expressed in candelas.

luminous-intensity distribution curve A

polar plot representing the light intensity as a
function of angle about a light source.

luminous-intensity distribution curve

luminous paint 1 . Phosphorescent paint,
which, after activation, continues to emit light
(even in darkness) for several hours. 2. Fluores-
cent paint, which has a high light reflectivity
because it reflects absorbed ultraviolet energy
as visible light.

luminous transmittance Of a lens, light dif-
fuses or the like: the ratio of the total transmit-
ted light to the total incident light.

609

lump lime

lump lime A high-quality quicklime.

lump sum agreement Same as stipulated

sum agreement.
lunding beam See tie beam.

lune A tapering wedge-shaped unit forming the
covering of a hemisphere.

lunette 1. A crescent-shaped or semicircular area
on a wall or vaulted ceiling, framed by an arch or
vault. 2. An opening or window in such an area.
3. A painting or sculpture on such an area.

luster 1 . An iridescent decorative surface
appearance. 2. A surface or coating which
imparts a gloss, sheen, glitter, or sparkle.

lute 1. A scraper having a straight cutting edge;
used to level plastic concrete. 2. A bricklayer's
straightedge used for striking off clay from a
brick mold. 3. See sulfur cement.

Lutheran window Same as dormer window.

luthern Same as dormer window.

lux The SI unit of illuminance equal to the illu-
mination on a surface, all points of which are at
a distance of 1 meter from a uniform point
source of 1 candela; 1 lux is equal to 1 lumen per
square meter (1 lm/m 2 ).

LWC Abbr. for lightweight concrete.

lx Abbr. for lux.

lyceum A building for general education by
means of public discussions, lectures, concerts, etc.

lych-gate, lich-gate A roofed gateway at the
entrance to a church or cemetery where a coffin

lych-gate

may be placed temporarily before proceeding to

the grave.
lychnoscope Same as low-side window,
lych- stone A stone at the entrance to a

churchyard, intended to receive a bier.
lying panel 1 . A panel so placed that the fibers

of the wood lie in a horizontal position. 2. A

panel whose longer dimension is in a horizontal

position. 3. Same as lay panel,
lysis A plinth or step above the cornice of the

podium of some Roman temples; when present

in a columnar edifice, it constitutes the stylobate

proper.

610

m Abbr. for "meter."

M 1. Abbr. for "thousand." 2. On drawings, abbr.
for bending moment.

macadam, tarmac, tarmacadam 1. A pav-
ing for roads or other surfaces, formed by
grading and compacting layers of crushed stone
or gravel; then the top layer(s) are usually bound
by asphaltic material, acting to stabilize the
stone, provide a smoother surface, and seal
against water penetration. 2. The crushed stone
used in a macadamized surface.

macadam aggregate A product manufac-
tured by crushing stone, slag, or gravel and
then screening it to a uniformly coarse size;
when compacted, void spaces are relatively
large.

Macassar ebony A hard, very heavy wood of
the East Indies; black with red or brown
streaks; used for decorative paneling and appli-
cations requiring high-impact or wear resis-
tance.

macellum A Roman meat or produce market
in a covered hall.

maceria In ancient Roman construction, a
rough wall having no facing; constructed in
a wide variety of materials.

machicolation An overhanging defensive
structure at the top of a medieval fortification,
with floor openings through which boiling
water or oil, missiles, etc., could be dropped on
attackers.

machicolation

machine bolt A threaded bolt having a
straight shank and a conventional head such as a
square, hexagonal, button, or countersunk type.

ri4 m R

1 >'f B

machine

bolt

machine burn A darkening or charring of
a surface due to overheating of the cutting
knives or abrasive belts during machining of the
material.

machine finish See smooth machine finish.

machine gouge A groove which results when
a machine cuts below the desired line of cut.

machinery room See mechanical equipment
room.

macroscopic Visible to the unaided eye.

made ground, made-up ground 1. Solid
ground formed by filling in an artificial or nat-
ural pit with hard rubble such as broken brick,
concrete, etc., or with rubbish. 2. See fill, 1.

made-up ground Same as made ground.

madrasah A theological school, generally ar-
ranged around a courtyard, from the 11th cent.
A.D. on, in Anatolia, Persia, and Egypt.

maeander See labyrinth fret.

611

maemanum

maenianum 1. In ancient Rome, a balcony or
gallery for spectators at a public show. 2. Origi-
nally, the balcony in the Forum at Rome, for
spectators of the gladiatorial combats.

magazine A storage place for ammunition and
explosives; also see powder house.

magazine boiler A coal- or coke-fired boiler
(in a hot-water or central heating system) which
has a bunker fitted to it, large enough to contain
24 hours of fuel.

magnesia A fine white powder of magnesium
oxide; gives brick a yellow tint.

magnesia cement Magnesium oxide mixed
with water, often with the addition of asbestos
fibers; used to cover steam pipes, furnaces, etc.

magnesia insulation Magnesium carbonate
hydroxide, with or without admixture of fiber
reinforcement or other materials; a good thermal
insulator because of the great number of closed
air cells it contains; molded into rigid boards,
blocks, or shapes conforming to piping.

magnesite A natural magnesium carbonate.

magnesite flooring A flooring material com-
posed of calcined magnesite, magnesium chlo-
ride, sawdust, ground quartz or silica, and fine
powdered wood waste; used as a finishing surface
on concrete floor slabs.

magnesium A gray-white, light metal (64%
the weight of aluminum); easily drawn and
machined; immune to alkalies.

magnesium alloy Any of a number of alloys
of magnesium; the usual additives are aluminum,
manganese, silicon, silver, thorium, and zirco-
nium, used singly or in combination.

magnesium carbonate See magnesia insula-
tion.

magnesium hydroxide A white powder
which is slightly soluble in water; in dolomitic-
type limes used in plaster, its presence helps the
lime to spread more easily.

magnesium lime Lime manufactured from
limestone; contains some magnesium; used as fin-
ish lime in plastering or as mason's lime in mortar.

magnetic bearing The bearing, 4 of a line
where the reference meridian is the local mag-
netic meridian.

magnetic catch A door catch that uses a mag-
net to hold the door in a closed position.

magnetic catch

magnetic core See core, 11.

magnetic declination At a particular loca-
tion, the horizontal angle between true meridian
(true north-south line) and magnetic meridian
(direction of compass needle).

magnetic switch An electric switch whose
switch contacts are controlled by means of an
electromagnet; esp. used in the control circuits
for motors.

magnetite A natural black oxide of iron, con-
taining from about 65 to 72% iron and some-
times a small amount of nickel and titanium;
used as an aggregate in high-density concrete.

mahlstick, maulstick A stick used by
painters as a rest for the hand while painting.

mahogany 1 . A straight-grained wood of inter-
mediate density, pinkish to red-brown in color;
found principally in the West Indies, and Cen-
tral and South America. Used primarily for inte-
rior cabinetwork and decorative paneling. 2.
Wood from a number of tropical species which
resemble mahogany, generally classified as to
origin, i.e., African mahogany, Philippine maho-
gany, etc.

maiden tower The keep or principal tower of
a castle.

mail box A multiple arrangement of boxes for
receipt and/or distribution of mail at a central

612

makeup air

point in a building; mainly used in apartment or
office buildings.

mail chute, letter chute A small shaft for
conducting letters from an upper floor to a post-
box on the ground floor.

mail slot, letter slot A small opening, often
with a hinged closer, which is set in an exterior
door, sidelight, etc., and through which mail is
delivered.

main l.In an air-conditioning system, a major
duct or pipe for distributing to or collecting from
various branches. 2. In any system of continuous
piping, the principal artery of the system to
which branches may be connected.

main bar A steel reinforcing bar in main rein-
forcement.

main beam A principal beam used to carry a
load, which transmits the load directly to the
columns.

main cable An electric cable which distributes
power to a group of buildings.

main contractor Same as general contractor.

main couple The principal truss in a roof.

main diagonal A diagonal member of a web,
joining the top and bottom chords of a truss.

main member, primary member In a

structural system, a member or component part
which is essential to the overall stability of the
structure.

main rafter A common rafter.

main reinforcement In reinforced concrete,

steel reinforcement which resists stresses result-
ing from applied loads and moments, as opposed
to reinforcement intended to resist secondary
stresses.

main runner A large supporting runner for a
suspended ceiling; a primary member of the sus-
pension system; usually l'/i-in. (3.8-cm) metal
channels, held by hangers or rods from the
building structure; used to support furring chan-
nels or rods to which lath is attached.

main sewer 1. A public sewer. 2. A sewer to
which one or more branch sewers are connected
and which serves a large area; also called a trunk
sewer.

main stack Same as vent stack.

maintainer Same as motor grader.

maintenance The upkeep of a building and its
equipment so that the building can continue to
perform its required functions. See condition-
based maintenance, corrective maintenance,
deferred maintenance, emergency maintenance,
periodic maintenance, planned maintenance, pre-
ventive maintenance, scheduled maintenance.

maintenance bond A bond that provides a
guarantee to an owner that the contractor will
rectify defects in workmanship or materials
reported to the contractor within a specified
time period following final acceptance of the
work under contract.

maintenance curve For a light source, same
as life performance curve.

maintenance factor The ratio of illumina-
tion on a given area after a period of time to the
initial illumination on the same area; used in
lighting calculations to account for the depreci-
ation of lamps or reflective surfaces (or the like).
Also see light loss factor.

maintenance finish A heavy-duty paint, var-
nish, or lacquer used to protect and decorate
industrial, institutional, and commercial build-
ings and structures.

main tie In a roof truss, a member which con-
nects the feet of the rafters.

main trap See building trap.

main vent The principal artery of the venting
system to which vent branches may be con-
nected; also called vent stack.

maison de maitre See Creole house.
maison de poteaux-en-terre See poteaux-

en-terre house.
maisonette Same as duplex apartment.

maison piece sur piece 1. In French vernac-
ular architecture of Louisiana, primarily in the
18th century, a dogtrot cabin consisting of two
single-room cabins separated from each other by
an open passageway which both cabins shared.
2. A one-room log cabin. See also piece sur piece
construction.

majolica A type of pottery decorated with an

opaque white glaze and a colored overglaze; a

type of faience tile.
makeup air Outdoor air which is supplied to

an HVAC system to replace exhaust air and any

air lost by exfiltration.

613

makeup water

makeup water Water which is supplied (as to
a steam boiler or cooling tower) to compensate
for losses by evaporation and leakage.

makore, African cherry, cherry mahogany
A moderately hard, heavy wood of West Africa,
pinkish to red-brown in color; resembles maho-
gany and American cherry; used for cabinets,
flooring, and plywood.

maksoorah In a mosque, an area which is
enclosed by a screen or partition and which
is reserved for prayer or surrounds a tomb.

malachite A carbonate of copper; green in
color; harder than marble; usually employed as
a highly polished veneer.

male connector Any type of electrical con-
nector having contacts which project into the
recessed opening of a female connector.

male plug An electric plug, 5 inserted into a
receptacle to form an electric connection.

male thread l.A thread on the outside of a
pipe. 2. Same as external thread.

mall l.A public plaza, walk, or system of walks,
often set with trees and designed for pedestrian
use. 2. See shopping mall. 3. A heavy wood mal-
let; a maul.

malleability The property of a metal that per-
mits mechanical deformation by extrusion, forg-
ing, rolling, etc., without fracturing.

malleable brass Same as Muntz metal.

malleable iron l.A white cast iron that has
been annealed; malleable cast iron. 2. Wrought
iron. A low-carbon cast iron that has been
annealed and allowed to cool slowly; capable of
being beaten into shape to form decorative iron-
work.

mallet A short-handled wooden hammer, used
by carpenters, stonecutters, etc., chiefly for driv-
ing another tool, as a chisel; the head may be of
a soft material such as plastic.

mallet-headed chisel A steel mason's chisel
having a rounded head.

malm 1. Earth containing a considerable quan-
tity of chalk in fine particles; a calcareous loam.
2. A malm brick.

malm brick A brick made of true or artificial
malm, the latter consisting of comminuted
chalk mixed with sand and pan breeze.

malm rubber A relatively soft malm brick
which can be rubbed to a desired shape.

Maltese cross A cross formed by four equal tri-
angles or arrowheads joined at their points.

maltha l.In ancient Roman construction, a
type of bitumen, various cements, stuccos, and
the like, used for repairing cisterns, roofs, etc.
2. A bituminous substance midway in consis-
tency between asphalt and petroleum.

malus In ancient Roman theaters and amphi-
theaters, one of the poles over which the velar-
ium was stretched.

MAN. On drawings, abbr. for "manual."

mandapa A large, open porch or hall of a
Hindu temple.

mandatory and customary benefits See
benefits.

mandatory standard A standard with which it
is obligatory to comply; established by an author-
ity endowed with the necessary legal power.

mandoral Same as mandorla.

mandorla, vesica piscis An aureole, almond-
shaped, depicted around the full form of a sacred
person.

mandrel, mandril l.A temporary internal
support for a light-gauge metal shell during a
pile-driving operation; takes the impact of the
pile hammer during driving and is then with-
drawn before concrete is placed in the shell; also
called a pile core. 2. A cylindrical bar or spindle,
used chiefly as a support during machining or
forming operations.

manganese A metallic element used as an
alloying element in steel as a hardener and deox-
idizer; also used as an alloying element in other
metals such as copper to introduce high
mechanical damping.

manganese drier Manganese acetate used in
paints to speed its rate of drying.

manganese greensand See greensand.

manganese steel A very hard, brittle steel
containing from 1 1 to 14% manganese and 1.5%
carbon; must be treated by cooling in water to
remove extreme brittleness; used where high
resistance to abrasion is necessary.

manger A trough in a stable for feeding cattle.

manhole A covered opening in a street which
provides access for cleaning and repairing of
a sewer beneath, or for repairing a conduit
for electric underground piping or electric cables.

614

mantelpiece

unsmmm

ihole

man»hour A unit of work equal to the output
of one man working for 1 hour.

manifold A section of duct, a fitting, or a pipe
with a number of branches which are close
together.

Mannerism Transitional style in architecture
and the arts in the late 16th cent., particularly in
Italy, characterized in architecture by unconven-
tional use of classical elements.

manometer An instrument for the measure-
ment of pressure; a U-shaped glass tube partially
filled with water or mercury, one side of which is
connected to the source of pressure. The amount
of displacement of the liquid is a measure of the
magnitude of the pressure.

manor house 1 . Usually, an imposing house in
a countryside, often the residence of a land-
owner with considerable acreage. 2. A relatively
simple one-room house of early colonists in
America, having a gable roof, clapboard walls, a
battened door, a window at the front of the
house with solid shutters, and a chimney at one
or at each end.

mansard roof 1 . ( US and Brit. ) A roof having
a double slope on all four sides, the lower slope
being much steeper. 2. (US) Same as gambrel
roof. 3. A hipped roof usually having a double
slope or compound curve on all four sides of the
roof, the lower slope usually being much
steeper than the upper slope; alternatively, the
sides may have a concave-, convex-, or S-

mansard roof

shape. 4. A sloping roof that projects from the
wall of a building and has a double slope, the
lower slope being steeper than the upper.

Mansard style 1. A term sometimes used as a
synonym for Second Empire style in the United
States. 2. An architectural style that makes use
of, or suggests, a mansard roof.

manse The dwelling of a clergyman.

mansion 1. A very large, imposing, stately resi-
dence. 2. In colonial times, the residence of a
landholder. 3. A manor house; also called a
mansion house.

mantel 1. A beam or arch that supports the
masonry above a fireplace; also called a mantel-
tree. 2. All the construction or facing around a
fireplace. 3. A mantelshelf.

mantel, 2

mantel board A wood mantelshelf.

mantelpiece l.The fittings and decorative
elements of a mantel above a fireplace. 2. A

615

mantel register

shelf above a mantel; often called a mantelshelf.
3. The construction that serves as a support for
the masonry above a fireplace. 4. A mantelshelf.

mantel register, cast-iron register A rela-
tively inexpensive prefabricated cast-iron man-
telpiece which screws onto the fireplace and
forms the fireplace surround.

mantelshelf That part of a mantelpiece which
constitutes a shelf.

manteltree A wood, stone, or iron structural
member that spans the opening over a fireplace.
Often, a large horizontal oak timber that serves
to support the wall construction above, typically
placed high enough above the hearth to prevent
its igniting; sometimes plastered to improve its
fire resistance.

mantle l.Same as mantel. 2. The outer cover-
ing of a wall which differs from the material of
the inner surface.

mantlet Same as chemise.

mantonium A fireproofing plaster composed
of equal parts of gypsum and exfoliated vermi-
culite; applied to structural steel elements as
fireproofing.

mantrap A short narrow section of corridor
purposely constructed to permit passage by
only one person; has interlocking doors at both
ends; used in some high-level security installa-
tions.

manual batcher A batcher equipped with
gates or valves which are operated manually.

manual call point A British term for fire
alarm box.

manual fire alarm system A fire alarm sys-
tem that is manually operated, so arranged that
the operation of any one station will ring all sig-
nals throughout the building as well as at one or
more selected locations.

manual fire pump A pump supplying water
to a sprinkler or standpipe system which is not
activated automatically and must be started by
hand.

manually-propelled mobile scaffold See

mobile scaffold.
manual operation Said of functioning of

equipment or devices that are capable of being

operated directly by hand without any other

source of power.

Manueline architecture The last phase of
Gothic architecture in Portugal, so named after
King Manuel I (1495-1521).

manufactured building A structure which is
substantially or wholly made in a manufacturing
plant for installation or assembly at a building
site.

manufactured home A manufactured build-
ing intended as a dwelling.

manufactured house Same as prefabricated
house.

manufactured sand A fine aggregate pro-
duced by crushing rock, gravel, or slag.

map A graphic, planar depiction of the earth's
surface, or a portion thereof, drawn to scale.

map cracks, map cracking See checking.

maple A hard, tough, moderately high-density
wood of North America and Europe, light to
dark brown in color; has a uniform texture; used
for flooring, wood turning, etc. Also see bird's-
eye maple.

maqsura An enclosure in a mosque which
includes the praying niche, made usually of an
openwork screen; originally meant for the sultan
during public prayers.

marb Abbr. for marble or "marbleized."
marble A metamorphic rock composed largely
of calcite or dolomite; often highly polished to
enhance its appearance; available in different
colors that result from differences in mineral
content.

marbled, marbleized Having the appearance
of marble, or made to look like marble by a spe-
cial application of paint, as in marbleized wood-
work, or by integral treatment, as in marbleized
plastic tile.

marbling, marbleizing The use of antiquing
techniques to achieve the appearance of marble
in a paint film.

marezzo, marezzo marble A cast imitation
marble produced with Keene's cement. Also see
artificial stone.

margin 1 . The exposed flat surface of the stiles
and rails which form the framing around a panel.
2. The projecting surface above the stair nosings
in a close string. 3. The mitered border around a
hearth. 4. The exposed surface of a slate or tile
which is not covered by the one above.

616

marquetry

marginal bar A glazing bar which divides a
glazed opening so that a central glazed opening
is surrounded by narrow panes at the edges.

margin draft In masonry, the plain-dressed
border on the face of a hewn block; the middle
part of the face may be dressed or left rough; also
see draft, 2.

margin light See side light.

margin of safety Same as factor of safety.

margin strip In flooring, a wood member
which forms a border.

margin trowel A plasterer's trowel which has a
box-like shape or sides which turn up so that it is
especially useful for working corner angles.

margin trowel

marigold window A round window whose
mullions of tracery radiate; a rose window.

marine glue Any glue which is insoluble in
water; usually contains a solution of rubber
and/or resins.

marine paint A paint formulated to withstand
exposure to sunlight and to fresh and salt water.

marine plywood Plywood in which the layers
of veneer (i.e., plies) have been cemented to
each other with a marine glue.

marked face The front or face side of a piece
of lumber.

marker A sign, plaque, or monument that des-
ignates a building, site of historic importance, or
boundary.

market cross Same as cross, 2 or a cross
located at the principal market place of a town.

market house, market hall Often, a one-
or two-story rectangular building where butch-
ers, fishmongers, grocers, and peddlers sell
their goods on the ground floor often open to
the outdoors; sometimes arches or heavy posts
support a second story that may house munici-
pal offices.

marketplace A building or open place in
which produce, usually of local origin, is sold.

marking gauge, butt gauge A carpenter's
tool for scribing a line parallel to an edge; con-
sists of an adjustable faceplate (which is run
along the edge) mounted on a rod containing a
marking point.

SPUR-

marking gauge

mark out In carpentry, to lay out the lines

where cuts are to be made.
marl An earthy deposit; a mixture of clay and

carbonate of lime.
marl brick, marl stock A superior brick

made from marl,
marmoratum In ancient Roman construction,

a cement formed of pounded marble and lime

mortar which were well mixed; used in building

walls, terraces, etc.
marmoset, marmouset An antic figure, usu-
ally grotesque, introduced into architectural

decoration in the 13 th cent.
marouflage A technique for fastening canvas

(or the like) to a wall by means of an adhesive.
marquee, marquise A permanent roof-like

shelter over an entrance to a building.

marquee

marquetry Inlaid pieces of a material, such as
wood or ivory, fitted together and glued to

617

martello tower

marquetry

a common background. Also see inlay and
in tarsia.

martello tower A defensive tower of the 16th
century; of Italian origin and usually circular.

martin hole See owlhole.

Martin's cement, hard-finish plaster Sim-
ilar to Keene's cement but contains potassium
carbonate as an additive in place of alum.

martyrium A place where the relics of a martyr
are deposited.

mascaron, mask The representation of a face,
a human or partly human head, more or less car-
icatured, used as an architectural ornament.

mascaron

mascaron stop A termination at the end of a

molding over a door or window. Also called a
mask stop.

mash hammer, mash In stoneworking, a
short-handled heavy hammer with two round or
octagonal faces.

mashrebeeyeh See meshrebeeyeh.

mask See mascaron.

masking 1. Preparing surfaces adjacent to
paintwork with a temporary covering of masking
tape, or tape plus paper, to keep them free of
paint. 2. Screening off part of a theater stage
from view of the audience. 3. The action of ren-
dering one sound inaudible or unintelligible as
the result of the presence of another (usually
louder) one.

masking tape An adhesive-backed paper tape
used in masking, 1.

mason A person who is skilled in the craft of
building with units of natural or artificial min-
eral products, such as bricks, stones, and cin-
derblocks, that are usually bonded or cemented
with mortar to similar units.

Masonite A proprietary name for a widely used
commercial hardboard.

masonry l.The art of shaping, arranging, and
uniting stone, brick, building blocks, etc., to
form walls and other parts of a building. 2. Con-
struction using masonry units of such materials
as clay, shale, glass, gypsum, or stone, set in mor-
tar; this term includes concrete masonry units
but excludes reinforced concrete.

masonry anchor The metal piece inside the
throat of a hollow-metal doorframe which
secures the frame to a masonry wall.

masonry block Same as masonry unit.

masonry bond See bond.

masonry-bonded hollow wall A wall built
of masonry units so arranged as to provide an air
space within the wall, and in which the facing
and backing of the wall are bonded together
with masonry units.

masonry cement Hydraulic cement for use in

mortars for masonry construction where greater
plasticity and water retention are desired than
are obtainable by the use of portland cement
alone; such a cement always contains one or
more of the following materials: portland

618

mason's lead

cement, portland-pozzolan cement, natural
cement, slag cement, and hydraulic lime, and
usually contains one or more of the following:
hydrated lime, pulverized limestone, chalk, talc,
pozzolan, clay, and gypsum; many masonry
cements also include entrained air and a water-
repellent.

masonry course A layer of masonry units run-
ning (essentially) horizontally in a wall.

masonry cramp A U-shaped metal fastener
used to hold adjacent units of masonry
together.

masonry drill Same as star drill.

masonry filler unit A masonry unit which is
used to fill the space between joists or beams,
providing a platform for a cast-in-place concrete
slab.

masonry grout Any cementitious mixture
used to fill voids in masonry.

masonry guard A plaster guard.

masonry joint Any joint between masonry
units bonded with mortar. See colonial joint,
concave joint, excess joint, extruded joint, flat
joint, flush-cut joint, hick joint, hungry joint,
keyed joint, raked joint, rodded joint, rough-cut
joint, ruled joint, scored joint, scribed joint, skin-
tied joint, spalled joint, struck joint, tooled joint,
troweled joint, V-joint, weather joint, weather-
struck joint. Also see pointing.

masonry mortar See masonry cement and
mortar.

masonry nail A hardened-steel nail with a
knurled or fluted shank; esp. used for fastening
to masonry.

masonry nail

masonry paint A durable paint expressly

designed to coat exterior masonry surfaces. Also

see cement paint.
masonry panel See prefabricated masonry

panel.
masonry reinforcement See reinforcement.
masonry tie 1 . See wall tie. 2 . See tie, 1 .
masonry unit A building unit fabricated of

burnt clay, concrete, stone, or the like.

masonry veneer A masonry facing laid against
a wall and not structurally bonded to the wall.

SHEATHING
PAPER

SHEATHING

BASE

FLASHING

MASONRY
VENEER

masonry veneer

mason's adjustable multiple-point suspen-
sion scaffold A scaffold having a continu-
ous platform supported by bearers suspended by
wire rope from overhead supports, so arranged
and operated as to permit the raising or lowering
of the platform to desired working positions.

mason's ax See axhammer.

mason's hammer A hammer with a heavy
steel head, one face of which is shaped like a
chisel for trimming brick or stone.

mason's hammer

mason's joint Same as mason's V-joint pointing.
mason's lead See lead, 1.

619

mason's level

mason's level A level similar to a carpenter's

level but longer.
mason's lime See building lime,
mason's mark See banker-mark.

mason's measure A measure of the quantity
of masonry units required for a job; corners are
counted twice, and no allowance is made for
small openings.

mason's miter, mason's mitre A masonry
joint having the appearance of a miter joint but
actually shaped from a single solid stone.

mason's putty A lime putty to which portland
cement and stone dust have been added; esp.
used in ashlar work.

mason's scaffold A totally self-supporting
scaffold, having two rows of standards, capable
of carrying unusually heavy loads.

mason's stop Same as mason's miter.

mason's V-joint pointing Pointing in which
the mortar is given a profile similar to a flattened
V; may also have a flat fillet at top and bottom.

masonwork Same as masonry.

mass bell Same as sanctus bell.

mass burning rate The loss of mass per unit
by materials burning under specified conditions.

mass center Same as center of gravity.

mass color When viewed by reflected light,
the color of a pigment-vehicle mixture which is
thick enough to completely obscure the back-
ground.

mass concrete Any volume of cast-in-place
concrete intended to resist applied loads by
virtue of its mass; generally cast as a monolithic
structure; usually incorporates a high propor-
tion of large coarse aggregate and a low cement
content.

mass curing The adiabatic curing of concrete
in sealed containers.

mass diagram A calculation employing a
graph portraying the cumulative quantities of
cut and fill along the center line (cut is shown as
a positive quantity and fill is shown as a negative
quantity); used to determine the haul.

mass foundation Any support for a structure
which is enlarged beyond the size required for
adequate strength; used to provide additional
inertia to dissipate or alleviate the undesirable
effects of vibration or impact.

massicot A yellow amorphous powder, the
crystalline form of which is litharge; used as a
pigment.

mass retaining wall A gravity wall.

masstone The undiluted color of a pigment or
pigmented paint film.

mast 1 . A tower which carries one or more load
lines. 2. The load-bearing component of a der-
rick, or the like.

mastaba A freestanding tomb used in ancient
Egypt, consisting of a rectangular superstructure
with inclined sides, from which a shaft leads to
underground burial and offering chambers.

mastaba

mast arm A bracket attachment to a lamppost
or pole from which a luminaire is suspended.

MasterFormat As illustrated in the definition
of contract documents, a uniform classification
system for construction specifications that is
divided into 1 6 sections, each of which is num-
bered and named.

master key A key that will operate a number
of different locks, each of which is different.

master mason An exceptionally well-qualified
mason in the Middle Ages; a position more or
less equivalent to that of an architect today.

master plan A plan, usually graphic and drawn
on a small scale but often supplemented by writ-
ten material, which depicts all the elements of a
project or scheme.

master plumber An individual licensed and
authorized to install and to assume responsibility
for contractual agreements pertaining to plumb-
ing, and to secure any permits required for
plumbing installations.

MASTERSPEC A proprietary master specifi-
cation for the construction industry developed
by the American Institute of Architects.

620

Matheson joint

master switch A single electric switch in a
wiring system which controls the supply of
power to a building, or the action of relays or any
other remotely operated devices.

mastic l.Any heavy-bodied, dough-like adhe-
sive compound. 2. A sealant with putty-like
properties. 3. A protective coating applied by
trowel or spray on the surface of thermal insula-
tion to prevent its deterioration and to weather-
proof it.

mastic asphalt See asphaltic mastic.

mat l.See matte. 2. See mattress. 3. A very
heavy, flexible blanket of steel mesh, woven wire
rope, or chain; used to confine fragments of rock
during blasting.

match In comparing two materials or construc-
tions: an exact or approximate replication.

matchboards Boards which have a tongue
along one edge and a groove along the other;
when installed, the tongue of one board fits into
the corresponding groove of the adjacent board
and holds it securely. Also see dressed and
matched boards.

TONGUE

HOLLOW

BACK

END GROOVE
matchboards

GROOVE

matched floor A floor laid with matchboards.
matched joint, match joint The joint along

the edge between two matchboards.
matched lumber Lumber having dressed

edges and prepared for tongue-and-groove

joints.

matched roof boards Matchboards used as
roof sheathing.

matched siding Same as drop siding.

matching A system of matchboards, or of
sheets of wood veneer, arranged to emphasize
grain pattern, as in book matching or herring-
bone matching.

matching, 2

match plane One of a pair of planes used to
prepare matchboards; one cuts the tongue along
the edge, and the other cuts the groove.

material costs The total costs of all materials
used on a construction project, including deliv-
ery, handling, waste, storage, and taxes.

material hose Same as delivery hose.

material platform hoist A suspended plat-
form, manually or power operated, for conveying
building materials and supplies; usually con-
trolled from a point outside the conveyance.

material sample A small piece of material,
which is representative of the whole, that a con-
tractor submits to the architect for approval;
includes color, finish, and/or texture.

materials cage An open platform on a vertical
hoist, used for lifting materials to upper floors
during construction of a building.

materials tower Same as hoist tower.

material supplier Same as supplier.

materiato A collective term for all timberwork
employed in Classical Roman roof construction.

mat foundation A large, thick concrete slab
that sustains the load imposed by a number of
columns and/or walls; also called a raft founda-
tion or floating foundation.

A-r

Matheson joint In wrought-iron pipe, a bell-
and-spigot joint.

621

MATL

MATL On drawings, abbr. for "material."

matrix 1. In mortar, the cement paste in which
the fine aggregate particles are embedded. 2. In
concrete, the mortar in which the coarse aggre-
gate particles are embedded.

matroneum In some religious settings which
do not allow the sexes to mingle, a gallery set
aside for women.

mat sink Same as mat well.

matsu A common Japanese pine; used in house
construction.

matte, mat, matt A surface finish which is
dull, with little or no gloss or sheen, and with
low light reflectivity.

matte dip A liquid dip composed of two parts
by volume of sulfuric acid to one part by volume
of nitric acid and saturated with zinc oxide or
sulfate; used to obtain a matte finish on metals.

matte- surfaced glass Glass, one or both sides
of which have been etched, ground, sandblasted,
etc., to provide diffusion of light.

matte varnish See flat varnish.

mattock A tool for loosening soil in digging;
shaped like a pickax, but having one of its ends
broad instead of pointed.

mattress A layer or slab of concrete, laid di-
rectly on the ground, which acts as a footing or
the like.

mature tree A tree having a trunk diameter
greater than that specified in the applicable
code.

maturing The aging and/or proper hardening
of a material, e.g., mortar, plaster, concrete, etc.

maturing bin See boiling tub.

maturity A measure of the developing of
strength in concrete; combines the effects of
curing temperature and time of hydration.

mat well At the entrance of an exterior door, a
depression in the floor to hold a fiber doormat.

maul, mall 1. A heavy, wooden mallet. 2. See
beetle.

maul

maulstick A mahlstick.

mausoleum 1 . A commemorative edifice for
the reception of a monument; a cenotaph. 2. A
sepulchral chapel to contain tombs.

MAX On drawings, abbr. for "maximum."

maximum acceptable pressure In a

water distribution system, the highest water
pressure that will not result in the premature
or accelerated damage of any component in
the system.

maximum demand l.The greatest load, 3
delivered to an electric system over a definitely
prescribed time interval. 2. The greatest flow of
water (or waste discharge) for all the fixtures in
a plumbing system in a building during a defi-
nitely prescribed time interval.

maximum overall length l.For a lamp bulb
having a single base, the dimension from the base
to the point on the bulb farthest away. 2. For a
lamp bulb with a base at each end, the maximum
dimension from base to base.

maximum rated load As applied to scaffolds,
the total of all loads including the working load,
the weight of the scaffold, and such other loads
as may be reasonably anticipated.

maximum size of aggregate The largest size
of aggregate particles present in sufficient quan-
tity to affect the physical properties of concrete;
generally designated by the sieve size on which
the maximum amount permitted to be retained
is 5 or 10% by weight.

maximum temperature period In auto-
clave curing, the time interval over which the
maximum temperature is held constant.

maximum working pressure The maxi-
mum pressure at which piping materials of the
"standard" or "normally used" type are safe to
use.

may A term which denotes an option or alter-
native. Compare with shall and should.

Maya architecture The architecture of the
Mayan people in Central America and Mexico
from the 4th to the 15th cent., principally of
pyramid temples with steep stairways.

Mayan arch A corbeled arch of triangular
shape common in the buildings of the Maya
Indians of Yucatan.

maze Same as labyrinth, 3.

622

mechanical-draft water-cooling tower

Mayan arch

M.b.m., MBM In the lumber industry, abbr.

for "thousand (feet) board measure."
MC 1 . Abbr. for "moisture content." 2. Abbr. for

"metal-clad." 3. Abbr. for "mail chute."
MC asphalt Same as medium-curing asphalt.
MCM Abbr. for "thousand circular mills." See

wire size.
meager lime Low-purity lime containing at

least 15% impurities.
meal house A structure once used for storing

grain that had been ground.
meander Same as Greek key.
meandering shear wall A shear wall that is

irregular in plan.
mean gradient Average slope (for example, of

a water pipe or drain pipe).
means of egress A continuous path of travel

from any point in a building or structure to the

outside at ground level.
means of escape See fire escape.
measured drawing An architectural drawing

of an existing building, object, site, structure, or

detail thereof; accurately drawn to scale on the

basis of field measurements.

measurement standard A prescribed proce-
dure for conducting a measurement in such a
way as to obtain reliable, reproducible results
with a specified level of accuracy.

measuring chain l.See chain. 2. See
Gunter's chain.

measuring frame Same as batch box.
meat house Same as smoke house.

MECH On drawings, abbr. for "mechanical."

mechanical analysis The process of deter-
mining particle-size distribution in an aggregate
or in a soil, sediment, or rock. Also see sieve
analysis and particle-size distribution.

mechanical application The application of
plaster or mortar by pumping and spraying,
rather than by hand with a trowel.

mechanical bond l.The keying of a plaster
coat: (a) with another coat or a plaster base
below or (b) as a result of plaster which is par-
tially troweled through metal lath. 2. In rein-
forced concrete construction, a bond between
concrete and specially shaped steel reinforcing
bars or rods.

mechanical connection The joining of two
or more elements by mechanical fasteners such
as bolts, rivets, or screws (but not by non-
mechanical means, such as by adhesives).

mechanical core Prefabricated piping for
plumbing and/or heating, prefabricated duct-
work, and/or prefabricated electric wiring, ready
for field installation with a minimum amount of
labor at the site.

mechanical-draft chimney A chimney in
which the draft is produced, wholly or partly, by
an auxiliary blower that either forces air into the
furnace or draws the gases and smoke from the
furnace and discharges them into the chimney.

mechanical-draft water-cooling tower A
water-cooling tower in which air is moved
through the tower by one or more fans built into
the tower.

. COOLING
| ~ t TOWER FAN

ELIMINATORS

SPRAYS-
PACKING 0R-"
SLATS

AIR INTAKE

mechanical-draft water-cooling tower

623

mechanical drawing

mechanical drawing A precise drawing, pro-
duced with the aid of instruments, as compasses,
triangles, T-squares, etc.

mechanical equipment room, machinery
room A room containing a permanently
installed refrigeration or air-conditioning sys-
tem, or major parts thereof.

mechanical equivalent of heat The num-
ber of units of mechanical energy equal to one
unit of heat, e.g., 778.2 ft-lb (107.6 kg-m) equals
1 Btu; 4-187 joules equals 1 calorie.

mechanical joint l.A gastight and water-
tight joint formed by joining metal parts through
a positive -holding mechanical assembly (such as
flanged joint, screwed joint, flared joint). 2. In
piping, a joint which typically consists of: (a) a
flange which is integrally cast with the bell of
the pipe, (b) a rubber gasket which fits into the
recess in the socket, (c) a follower ring which
compresses the gasket, and (d) nuts and bolts
used to tighten the joint.

Nut

Cast-iron gland

/ T-bolt

Gasket

r^wwwwwK^

Cast lug

77/////////}

>Pipe

\— l~7~7f U J A

■/////////

typical mechanical joint

mechanically foamed plastic A cellular
plastic whose structure is produced by physically
incorporated gases.

mechanically galvanized nail, peen-
coated nail A nail which is zinc-coated by
tumbling in a container with powdered zinc and
small glass beads.

mechanical operator A mechanism for
opening and closing side -by-side windows in fac-
tories, gymnasiums, etc., either by manual oper-
ation with a hand crank, handwheel, or hand
chain, or by an electric motor drive.

mechanical property A property of a mate-
rial that is associated with elastic and inelastic
reaction when force is applied, or that involves
the relationship between stress and strain.

mechanical room See mechanical equipment
room.

mechanical saw See band saw, circular saw,
jigsaw.

mechanical stoker A device which automat-
ically feeds a solid fuel (such as coal) into a com-
bustion chamber of a boiler or furnace, and
provides air for proper combustion; may include
a means for automatically removing solid prod-
ucts of combustion.

mechanical trowel A trowel consisting
of power-driven metal or rubber blades for
smoothing.

mechanical ventilation The process of sup-
plying outdoor air to a building or removing air
from it by mechanical means, e.g., with fans; the
air which is supplied may or may not be heated,
cooled, or air-conditioned.

mechanic's lien A lien on privately owned
real property created by state statute in favor of
persons supplying labor or materials for a build-
ing or structure or improvements thereof, gener-
ally for the value of the labor or materials
supplied by them. In some states, a mechanic's
lien also exists for the value of professional ser-
vices. Laws differ greatly among states as to the
circumstances in which such a lien may arise, the
sum for which it may be imposed, and the proce-
dures whereby the sum due may be collected or
the lien discharged. In most circumstances, clear
title to the property cannot be obtained until the
claim on which the lien is based has been settled.

mechanized parking equipment Devices
in mechanical parking garages that are used
exclusively for conveying automobiles, by means
of a power-driven transfer device, directly into
parking spaces or cubicles.

MED On drawings, abbr. for medium.

medallion l.An ornamental plaque (often
round, oval, or square, but may be of any other
form) representing an object or design in relief,
such as a figure, flower, or head. 2. A ceiling
ornament, often cast in plaster, at the center of
which is often hung a chandelier or luminaire;
also called a rose or rosette.

624

medullary ray

medallion molding A molding consisting of a
series of medallions, found in the later and richer
examples of Norman architecture.

medallion molding

medicine cabinet A storage cabinet for med-
ical supplies, toilet articles, and the like.

Medieval architecture Architecture of the
European Middle Ages, from about the 5th to
the 15th centuries. Found, in particular, in the
pre-Romanesque, Romanesque, and Gothic
styles.

Mediterranean Revival An imprecise term
(not a Revival architecture, as the name implies)
for a mixture of Mission Revival, Italian Villa
style, and Spanish Colonial Revival, particularly
in the latter part of the 20th century; usually
applied to a one- or two-story house with a red tile
roof and stuccoed walls, usually having rounded
or arched windows; occasionally referred to as
Mediterranean style.

medium The liquid or semiliquid ingredient of
a paint which controls ease of application,
appearance, gloss, adhesion, durability, and
chemical inertness.

medium-carbon steel Steel having a carbon
content between 0.3 and 0.6%.

medium-curing asphalt Liquid asphalt com-
posed of asphalt cement and a kerosene-type
diluent of medium volatility.

medium-curing cutback See medium-curing
asphalt.

medium-density fiberboard, medium-
density hardboard Fiberboard having a
density of from 30 to 50 lb per cu ft (480 to
800 kg per cu m); used for structural building
applications, coreboards, etc.

medium-density overlay An overlay of
paper impregnated with a thermosetting resin;
applied by a hot-press to plywood, fiberboard,

particleboard, etc., usually to improve its appear-
ance and durability.

medium-duty scaffold A scaffold designed
and constructed to carry a working load not to
exceed 50 lb per sq ft (245 kg per sq m).

medium oil varnish A varnish containing
between 5 and 15 gal oil per 100 lb (0.5 and 1.5
liter oil per kg) gum; used for interior paints and
varnishes.

medium relief Same as mezzo-relievo.

medium steel Steel neither very hard nor
very soft, usually contains from 0.25 to 0.5%
carbon.

medium-temperature water-heating sys-
tem A heating system in which water having
supply temperatures between 250°F (121°C)
and 350°F (177°C) is used as a medium to
convey heat from a central boiler, through a
piping system, to suitable heat-distributing
devices.

medium voltage According to ANSI/IEEE
standards, a nominal system voltage of between
1000 and 72,500 volts.

medullary ray, pith ray In a cross section
of a tree or log, one of the ribbons of tissue
extending radially from the pith; may vary
from microscopic to 4 in. (10 cm) or more in
oak; used to store and transport food horizon-
tally within the tree.

AXIS OF

TREE

MEDULLARY
RAYS

medullary rays

625

meeting house

meeting house A house of worship for some
Protestant faiths; also may serve as a center of
community activity; usually a notably plain
structure, often having a square floor plan.

meeting post, miter post The outer stile of a
lock gate which meets, at the middle of a gate-
way, the corresponding stile of the companion
gate.

meeting rail In a double-hung window, the
horizontal member at the top of the lower sash
or the horizontal member at the bottom of the
upper sash.

1 +

MEETir

: rail

JG
1

meeting rail

meeting stile One of the abutting stiles in a

pair of doors or sashes.
megalithic Built of unusually large stones.

megalithic monument

megalopolis, megapolis A thickly populated
urban region usually consisting of one or more
large cities and surrounding suburbs.

megaron l.In many Greek temples, a space
divided off and sometimes subterranean, where

only the priest was allowed to enter. 2. The great
central hall of a palace.

megascopic Visible to the unaided eye.

megilp In painting, a vehicle made of oil of
turpentine and pale drying oil in equal propor-
tions.

mehrab Same as mihrab.

MEK See methyl ethyl ketone.

melamine formaldehyde A colorless alkyd-
type synthetic resin which is resistant to alkalies
and most acids; used for surfacing plywood, chip-
board, etc.

melon dome A melon-like ribbed dome
(either an exterior or interior dome), especially
found in Islamic architecture.

MEMB On drawings, abbr. for "membrane."

member In structural engineering, a compo-
nent part of a structure, complete in itself.

membrane In built-up roofing, a weather-
resistant (flexible or semiflexible) covering
consisting of alternate layers of felt and bitu-
men; fabricated in a continuous covering and
surfaced with aggregate or asphaltic material.

membrane curing A process in which
either a liquid sealing compound (e.g., bitumi-
nous and paraffinic emulsions, coal-tar cut-
backs) or a nonliquid protective coating (e.g.,
sheet plastics) functions as a film to restrict
evaporation of mixing water from a fresh con-
crete surface.

membrane fireproofing A lath and plaster
membrane that provides resistance to fire and
extreme heat.

membrane forces Direct and shear forces
that act entirely within a thin concrete shell.

membrane roofing See membrane.

membrane theory In the design of thin
shells, a theory assuming that a shell cannot
resist bending because it deflects, and that the
only stresses in any section are shear stress and
direct compression or tension.

membrane waterproofing A membrane

applied to a surface to make it impervious to

water.
MEMO On drawings, abbr. for "memorandum."
memorial An architectural or sculptural object

or plaque commemorating a person or an event.

626

mercury lamp

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WATER TABLE

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membrane waterproofing

memorial arch An arch commemorating a
person or event, popular during the Roman
Empire, and again at the time of Napoleon and
later.

*si*i>v

memorial arch at the F'

orum, Komc

memorial park A cemetery, usually having
grave markers flush with the ground in large
open meadows bordered by groves of trees.

memorial plaque A flat marker, usually of
metal or stone and often inscribed, affixed to or
set into a surface; used to serve as a memorial or
to commemorate a special event.

memorial stone, memorial tablet A stone
or tablet set up, or placed on or in a wall, to com-
memorate some person or event.

memorial window In a church, a stained
glass window dedicated to the memory of a per-
son or family.

memory The quality of a material that enables
it to return to its original shape after it has been
compressed or stretched.

mending plate A steel strip, usually predrilled
with staggered screw holes; used to strengthen
joints in wood construction.

menhir A prehistoric monument consisting of
a single large standing stone, sometimes rudely
sculptured.

mensa 1. The stone slab or other piece forming
the top of an altar. 2. The upper surface of an
altar.

mensao Same as menhir.

mensole Same as keystone of an arch.

men's room In a public building, a room con-
taining toilet and lavatory facilities for the use
of men.

mensuration 1 . The process or art of measuring.
2. The branch of mathematics dealing with the
determination of length, area, or volume.

MER Abbr. for mechanical equipment room.

mer The smallest repetitive unit in the structure
of a high polymer.

mercantile occupancy The use of rooms,
stores, markets, buildings, or structures for the
display and sale of merchandise.

merchant bar iron Obsolete name for wrought
iron bars and rods.

merchant pipe A pipe which is not of standard
full weight; usually 5 to 8% lighter.

mercury-contact switch A wall-mounted
switch used in interior electric wiring; contains a
sealed glass tube of mercury which provides a
silent contact when the switch is turned on.

mercury lamp A high- intensity electric-
discharge lamp consisting of an electric arc in
mercury vapor in a sealed tube, which in turn may
be enclosed in an outer glass envelope; the light
produced appears blue-white, but contains only
violet, blue, green, and yellow components; usu-
ally operates slightly above atmospheric pressure.

627

mercury switch

5ame as mercury-contact

mercury switch

switch.

mercury-vapor lamp An electric-discharge
lamp consisting of an electric arc in mercury
vapor in a sealed tube, which in turn may be
enclosed in an outer glass envelope; the light
produced appears to be blue-white, but contains
only violet, blue, green, and yellow components.
The lamp is said to be "low pressure" if the par-
tial pressure of the vapor is below 0.001 atmo-
sphere, and "high pressure" if about an
atmosphere.

meridian stone A stone placed along a merid-
ian (i.e., an accurately determined line running
north and south) to delineate the eastern or
western boundary of a town or village.

merlon In an embattled parapet, one of the
solid alternates between the embrasures. Also
see battlement.

merlon

meros The frontal area between two grooves of
a triglyph.

mesaulos In an ancient Greek house: 1. A pas-
sageway connecting the andron with the gynae-
ceum. 2. The door in this passageway.

mesh 1 . The number of openings per inch in
wire cloth; a 100-mesh screen has 100 openings
per inch in each direction. 2. A network of
metal wires or the like. 3. Expanded metal,
light-woven steel, or welded steel used as rein-
forcement in concrete.

mesh-core door, cellular-core door A
hollow-core door of wood construction; the core
consists of a cellulose mesh grid or honeycomb
which is encased by wood rails and stiles; face
panels are fixed to the core with a waterproof
adhesive.

mesh partition A partition constructed of a
framework which is closed by heavy wire mesh;
acts as a barrier against unauthorized entry, but
provides for the passage of air, heat, and light;
does not obstruct operation of a sprinkler system;
used to protect and secure an area, such as a
stockroom.

meshrebeeyeh, mashrebeeyeh, mouch-
araby, mushrabiya 1 . An elaborately turned
wood screen enclosing a balcony window in an
Arabic structure. 2. Such a screen otherwise
used. 3. A balcony with a parapet and machico-
lations projected over a gate to defend the
entrance; the parapet may be either embattled or
plain.

meshrebeeyeh, 1

meshrebeeyeh, 3

mesh reinforcement In reinforced concrete,
an arrangement of steel bars or wire normally in
two directions at right angles, tied or welded at
the intersections or interwoven.

Mesoamerican architecture Architecture
of the area of Mexico and Central America in
which the presence of certain pre-Hispanic
cultural traits permits the classification of cul-
tures of the region as one civilization; includes
central and southern Mexico, the Yucatan

628

metal roof covering

peninsula, Guatemala, El Salvador, and parts
of Honduras, Nicaragua, and northern Costa
Rica.

Mesopotamian architecture Architecture
developed by the Euphrates and Tigris Valley
civilizations, from the 3rd millennium to the 6th
cent. B.C. Primarily a massive architecture of
mud bricks set in clay mortar or bitumen. The
heavy walls were articulated by pilasters and
recesses; important public buildings were faced
with baked or glazed brick. Rooms were narrow
and long and generally covered by timber and
mud roofs, but in certain cases also by tunnel
vaults; columns were seldom used; openings usu-
ally were small.

messmate A variety of eucalyptus wood; used
as timber for rough work.

messuage A dwelling with all attached and
adjoining buildings and curtilage together with
adjacent lands used by the household.
MET. On drawings, abbr. for "metal."
meta In a racetrack, a column or monument to
mark a turn.

metal-arc welding See arc welding.
metal ceiling See pressed-metal ceiling.
metal-clad cable See armored cable.

metal-clad fire door, Kalamein fire door

A flush door consisting of a wood core, or stiles
and rails and heat-insulated panels, covered
with sheet steel.

metal curtain wall An exterior building wall
which carries no roof or floor loads and consists
entirely or principally of metal, or a combina-
tion of metal, glass, and other surfacing materials
supported by a metal framework.

metal extrusion Same as extrusion, 1.

metal floor decking Formed sheet metal

decking, 2 for structural load-carrying purposes

in floor construction.
metal grating An open metal flooring for

pedestrian and/or vehicular traffic, covering

floor depressions or openings.

metal halide lamp, metallic-additive lamp

An electric-discharge lamp in which the light is
produced by the radiation from a mixture of a
metallic vapor (e.g., mercury) and the products
of the dissociation of halides (e.g., halides of
thallium, indium, sodium, etc.).

metal lath, metal lathing, steel lathing A

base for plaster fabricated: (a) by slitting metal
and then stretching it to form a diamond-shaped
mesh or (b) by punching and forming sheet
metal. Usually classified as rib lath, diamond'
mesh lath, sheet lath, or wire lath.

PLASTER

METAL
LATH

metal lath

metal leaf A very thin sheet of metal, such as
gold or silver, used in decoration or in lettering;
after application, the surface may be protected
against oxidation by a thin coating of shellac or
lacquer.

metallic -additive lamp See metal halide lamp.

metallic area Of a wire rope, the sum of the
cross-sectional areas of all of the strands of
which it is composed.

metallic paint A paint or lacquer containing
metal flakes which reflect light.

metallic-sheathed cable See armored cable;
BX.

metallic tubing See electrical metallic tubing.

metallize To apply a coating of metal on a base
material, usually by spraying the coating metal
in a molten state.

metallized lamp bulb A lamp bulb having a
metallic-film coating on a portion of either the
inner or the outer surface to change the direc-
tion of the emitted light.

metal-molding See surface metal raceway.

metal pan See perforated metal pan.

metal primer The first coat of paint on metal;
a primer, 1 coat.

metal roof covering Sheet metal or shingles,
often corrugated or otherwise shaped, for appli-
cation on a roof framework or on a solid roof
surface; also see sheet-metal roofing.

629

metal sheeting

metal sheeting Same as sheet metal.

metal siding An exterior wall siding fabricated

of metal, usually aluminum.
metal structural cladding A nonload-bear-

ing cladding for exterior walls and sloping roofs;

fabricated of metal.
metal tie See tie, 1 ; see wall tie.
metal trim A piece of metal which protects the

edges, joints, or ends of another material, such as

plaster.

metal valley A velley gutter lined with metal.

metal window A metal frame, with or without
a sash, which accommodates glazing.

metamer A light, 2 of the same color as another
light, but of different spectral power distribution.

metamorphic rock Rock which has been
altered in appearance, density, and crystalline
structure (and in some cases mineral composition)
by high temperature and/or high pressure; e.g.,
slate is a metamorphic rock derived from shale.

metatome The space between two dentils.

meter, metre (m) The International Stan-
dard unit of length; equal to 39.37 inches.

meter-candle, metre-candle See lux.

metered demand The maximum rate of the
consumption of electric power or water in a
building supplied by a utility.

meter rod Same as precise leveling rod.

meter stop An off-on valve in a water service
pipe for stopping the flow of water to a building.

,• a

BUILDING FOUNDATION
meter stop

metes and bounds The boundaries, property
lines, or limits of a parcel of land, defined by dis-
tances and bearings, 4.

methylated spirit A mixture of ethyl alcohol
and a small amount of methyl alcohol; used
industrially as a solvent for paints, lacquers, and
varnishes.

methyl cellulose A granular, white flaky
material which acts as a water-soluble thickener
and stabilizer; used in water-based paints.

methyl chloride A gas which liquefies under
compression; used as a refrigerant.

methyl ethyl ketone, MEK A strong, aro-
matic, flammable solvent used in paints, var-
nishes, and lacquers.

methyl methacrylate A tough, rigid, trans-
parent acrylic plastic having good resistance to
common solvents and acids; subject to crazing.

metoche Same as metatome.

metope The panel between the triglyphs in the
Doric frieze, often carved. Also see triglyph.

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metope

metre See meter.

metric modular unit A brick whose dimen-
sions are multiples of 10 cm.

metric sabin A unit of sound absorption equiv-
alent to 1 sq m of perfectly absorptive surface.

metric ton Same as tonne.

metriostyle Intercolumniation in which the

space between two adjacent columns is of

medium distance.

630

mid-wall column

meurtriere Same as gun hole.

mews l.The royal stables in London, so
called because they were built where the king's
hawks were kept; hence, a place where carriage
horses are kept in cities or large towns. 2. An
alley or court in which stables are or once were
located.

MEZZ On drawings, abbr. for mezzanine.

mezzanine, entresol 1. A low-ceilinged story
or extensive balcony, usually constructed next
above the ground floor. 2. In a theater, the lowest
balcony or the forward part of the first balcony.
3. A space under the stage used for the manipula-
tion of scenery in connection with a plateau lift
system.

mezzo-relievo Midway between high-relief
and bas-relief.

MF Abbr. for "mill finish."
MFG On drawings, abbr. for "manufacturing."
MG On drawings, abbr. for "motor generator."
MH On drawings, abbr. for manhole.
MI On drawings, abbr. for malleable iron.
MIA Abbr. for "Marble Institute of America."
mica A naturally occurring silicate; used in
paints to improve suspension and brushing prop-
erties and to improve resistance to moisture pen-
etration; also used as a filler in plastics and in
electrical and thermal insulators.

mica pellets Pellets of exfoliated vermiculite.

mica powder Very small flakes of mica (or
ground mica) used in the manufacture of asphalt
shingles and roofing and as a filler in paints.

microbar Same as a dyne per square centimeter.

micro crack A crack that is too fine to be seen
by the naked eye but can be detected by use of
electronic measurement equipment.

micron A unit of length equal to a thousandth
part of a millimeter or a millionth of a meter.

microorganisms In paint technology, bacteria
and fungi which are harmful to liquid paint and
dry paint films. Bactericides and fungicides are
added to paints to inhibit the growth of these
organisms.

microphone A device which converts sound
waves into essentially equivalent electric waves;
the sound waves move an element in the device
which generates an electric voltage.

microsand An aggregate, essentially free of
clay and shale, that is sufficiently fine to pass
through a No. 100 (150 |im) sieve.

microscopic Observable only with the aid of a
microscope.

microstrainer A fine sieve used in the initial
stage of water filtration.

microwave motion detector A device that
generates a train of microwaves having a fixed fre-
quency in a space that is to be protected. If
an intruder enters and moves in the protected
area, waves reflected off the intruder's body will be
of a slightly different frequency. This change in
frequency is detected, thereby activating an alarm.

mid-Colonial architecture A term occa-
sionally used for Georgian style architecture.

Middle Pointed style Same as Decorated
style of Gothic architecture.

middle post 1. A king post. 2. A lock rail.

middle rail An intermediate horizontal struc-
tural member of a door between the stiles; if it
contains a lock, it is called a lock rail.

middle strip In flat concrete slab framing, the
slab portion which occupies the middle half of
the span between columns.

midfeather l.See parting slip. 2. A longitudi-
nal division or partition, as a withe in a chimney
or as in a cased frame.

midrail A rail approximately midway between
the guardrail and platform, secured to the
uprights erected along the exposed sides and
ends of platforms.

mid-wall column A column which carries a
part of a wall much thicker than its own diameter.

mid-wall column

631

Miesian

Miesian A term descriptive of the style of
Ludwig Mies van der Rohe (1886-1969), a
German- American architect who was a princi-
pal exponent of the International style. An out-
standing example of his work is the Seagram
Building in New York City (1958), designed by
Mies with Philip Johnson (1906- ).

migration The spreading or creeping of a
sealant onto adjacent surfaces, usually to the
detriment of bond.

mihrab A niche in the mosque or any religious
Muslim building indicating direction of prayer
toward Mecca. Focal point of decoration with
dome in front.

mihrab with the minbar on the right

mil, MIL 1 . A unit of measure equal to a thou-
sandth of an inch (0.0254 mm). 2. On drawings,
abbr. for "military."

mildew A fungus that grows and feeds on paint,
cotton and linen fabric, etc., which are exposed
to moisture; causes discoloration and decompo-
sition of the surface.

mildewstat A chemical agent which inhibits
the growth of mildew.

mild steel 1. Nearly pure iron having a very
low carbon content, usually between 0.15 and

0.25%; a ductile, rust-resistant material used in
boilers, tanks, enamelware, etc. 2. Same as low
steel.

milestone, milepost A marker showing the
distance in miles from a designated location;
before the 19th century, such markers were espe-
cially helpful to those traveling between outly-
ing communities.

mile-yard A unit equivalent to hauling one
cubic yard a distance of 1 mile; used (in the US)
in determining the cost of movement of excava-
tions.

milk house Before the 19th century, a small
subsidiary structure in which milk and other
dairy products were stored at a lowered tempera-
ture with cooling usually provided by slowly run-
ning cold spring water or the runoff from an
icehouse; typically had overhanging eaves to
shade it, and double walls and ceiling filled with
a thermal insulator, such as sawdust; commonly
had a concrete floor to promote cleanliness and
louvers for ventilation; was separated from the
barn for reasons of sanitation. This term replaced
by the word dairy in the 1800s; health regulations
have now made such structures obsolete.

milkiness A white, semiopaque discoloration

in a clear varnish film.
milk of lime A slaked lime and water solution.
milk paint Same as casein paint.

mill l.To remove metal by a circular tool hav-
ing teeth, as by use of a milling machine. 2. A
machine for rolling plates, shapes, rails, etc. See
bark mill, bolting mill, gristmill, sawmill, textile
mill, tide mill, water mill, windmill.

mill construction See heavy timber construc-
tion.

milled lead Same as sheet lead.

milled lumber Lumber that has passed through
a milling machine.

milled surface The surface obtained when
metal is removed by a milling machine.

mill file A single-cut file having a rectangular
cross section.

mill finish The finish on a metal sheet, bar, etc.,
which is produced by cold rolling or extrusion.

milliarium A column placed at intervals of one
Roman mile (equivalent to 0.92 mile or 1.48 km)
along a Roman road to indicate distance.

632

mineral fiber pad

milliarium aureum A golden column erected
by Augustus in 29 B.C. at the point where the
principal roads of the Roman empire termi-
nated.

millilambert A unit of luminance equal to
1/(1,000 k) candela per sq cm.

milling l.In stonework, the processing of
quarry blocks, through sawing, planing, turning,
and cutting techniques, to finished stone. 2. In
metalwork, the process of dressing a surface with
various shapes of rotary cutters to produce a flat
or grooved surface. 3. See knurling.

milling machine A machine consisting of a
rotating mandrel carrying a milling cutter, and a
movable table, operated by a feed screw, to
which is bolted the object to be milled.

milliphot A unit of illumination equal to
1/1,000 lumen per sq cm.

mill length, random length Run-of-the-
mill length of pipe, usually 16 ft to 20 ft (approx.
4.9 m to 6 m).

mill material Steel-mill products ordered expli-
citly for a particular job.

mill-mixed, ready-mixed Descriptive of a
product that is formulated and dry-mixed by the
manufacturer; only the addition of water is
required at the job site.

mill practice Standardized fabrication or
rolling procedures of a specific mill or of an
industry, usually applicable to structural steel.

mill run Products from a mill which have not
been graded or inspected.

mill scale A loose coating of oxide which forms
on iron or iron products when heated.

millwork Ready-made products which are man-
ufactured at a wood-planing mill or woodwork-
ing plant: moldings, doors, door frames, window
sashes, stair work, cabinets, etc.; normally does
not include flooring, ceilings, and siding.

milori blue High-quality pigment of the ferric-
ferrocyanide family mixed with gypsum or bar-
ium sulfate; used in lacquers.

mimbar Same as minbar.

min, MIN l.Abbr. for "minute." 2. On draw-
ings, abbr. for "minimum."

minah See minar.

minar, minah A tower, usually a memorial
monument, found esp. in India.

minaret A tall tower in, or contiguous to, a
mosque with stairs leading up to one or more bal-
conies from which the faithful are called to
prayer.

Persian portal with dome, flanked by minarets

minbar The pulpit in a mosque.

minchery A nunnery.

minch house A roadside inn.

mineral aggregate See aggregate.

mineral black, slate black Black pigment
obtained from crushing and grinding black
earth deposits, such as slate, coal, coke, or
shale.

mineral dust A very finely divided mineral
product, the greatest bulk of which will pass
through a 74-micron (No. 200) sieve; the most
common such material is pulverized limestone.

mineral fiber A fiber manufactured from glass,
rock, or slag (with or without a binder) generally
for use in fabricating heat insulation.

mineral fiber pad In a perforated-metal-pan
acoustical ceiling assembly, the porous sound-
absorptive element laid into the pan; may be
enclosed in a thin, sound-transparent envelope
of paper or plastic.

633

mineral fiber tile

mineral fiber tile An acoustical tile formed of
mineral or glass fiber and a binder.

mineral-filled asphalt Asphalt containing an
appreciable percentage of very finely divided
mineral matter which passes through a 74-
micron (No. 200) sieve.

mineral filler Any finely ground mineral sub-
stance, usually inert, used as a filler.

mineral flax Fibrous asbestos; used in the man-
ufacture of asbestos cement products.

mineral granules A natural or synthetic
aggregate used to surface roofing material.

mineral-insulated cable An electric cable
consisting of one or more conductors embedded
in an insulating material of a highly compressed
refractory mineral; has an outer sheath of con-
tinuous seamless tubular copper.

mineral pigment See earth pigment.

mineral spirit, petroleum spirit A flam-
mable thinner having a low-aromatic hydrocar-
bon content obtained in petroleum distillation;
widely used in paints and varnishes. Also see
odorless mineral spirit.

mineral streak A dark green or brown stain in
hardwoods; usually results from an injury during
growth.

mineral-surfaced felt A heavy, saturated
roofing felt which is coated on both sides with
asphalt; the top surface is covered with particles
of slate or stone; used on both sloped and flat
roofs.

mineral turpentine Same as white spirit.

mineral wool A wool-like material of fine
inorganic fibers such as asbestos or those made
from molten rock, slag, or glass; used as loose fill
or formed into blanket, batt, block, board, or
slab shapes for thermal and acoustical insula-
tion; also used as reinforcement for other mate-
rials such as insulating cements and gypsum
wallboard.

minimalist architecture Architecture that
follows the doctrine that the use of all decorative
elements, including ornamentation and color,
should be held to an absolute minimum. This
tenet considers all such architectural features to
be nonessential and of negative aesthetic value,
thus promoting the concept attributed to Mies
van der Rohe that "less is more."

minimum acceptable pressure In a water
distribution system, the lowest water pressure
permitting safe, efficient, and satisfactory opera-
tion at the most hydraulically remote fixture or
component in the system.

minium Naturally occurring red lead oxide;
used as a pigment.

miniwarehouse A warehouse that is subdi-
vided into a number of small, separate spaces,
each with its own lock.

Minoan architecture The architecture of
Bronze Age Crete, which reached its apogee
between the 19th and 14th century B.C. Most
important were its palaces, in which a great
number of rectangular rooms of various sizes,
serving different functions and connected by
long labyrinthine passages, were clustered
around a large central courtyard. Gate build-
ings with columnar porches provided access to
the otherwise unfortified compounds, which
were generally constructed on sloping sites, uti-
lizing terracing and split and multilevel organi-
zation of buildings with a great number of open
and enclosed stairs; light wells, air shafts, elab-
orate drainage and sewage systems, and flushing
toilets were the engineering features. Founda-
tion walls, piers, lintels, and thresholds were
built in ashlar stone; upper walls and stories in
timber framework with rubblestone masonry
faced by stucco and decorated by wall paint-
ings. Ceilings were of wood, as were the fre-
quently used columns with their typical
downward-tapering shape.

minor change A change of minor nature in
the work not involving an adjustment in the
contract sum or contract time, which may be
effected by field order or other written order
issued by the architect.

minster A monastic church; since many
English cathedrals were originally associated
with monasteries, the term applies to them by
extension.

minstrel gallery A small balcony on the
inside of a church or manor house hall, usually
over the entrance.

minute One division of a module, 3.

mirador In Spanish architecture and deriva-
tives, a lookout, whether an independent struc-
ture, a bay window, or a roof pavilion.

634

mission dormer

mirror l.A nearly perfect reflecting surface.
2. A small oval ornament surrounded by a mold-
ing.

MISC On drawings, abbr. for "miscellaneous."

miscellaneous storage According to NFPA
standards concerning the storage of goods in a
building, storage that does not exceed 12 feet
(3.7 m) in height and which is incidental to
another occupancy use group.

miserere, subsellium A ledge on the bottom
of a hinged seat in a church; when the seat is
raised, the ledge provides some support for a wor-
shiper or choir singer who, in standing, leans
against it.

miserere

misericord 1. In monastic architecture, a room
or separate building where monastic rule was
relaxed. 2. Same as miserere.

mismatched l.Said of adjacent boards or
veneers in which there is an absence of symme-
try. 2. Said of a poorly fitting joint.

mismatch lumber Lumber or boards which
are dressed and match but have edge details that
do not fit properly.

mission In Spanish Colonial architecture, a
church and complex of buildings usually depen-
dent for support on a monastic order or a larger
church.

Mission architecture Church and monastic
architecture of Spanish religious orders, espe-
cially in the Americas in the 18th century,
displaying considerable regional variation as a
result of influences of skills of local laborers
and the availability of construction materials;

mission architecture

relatively unadorned in some regions but con-
siderably more elaborate in others, often with
ornamentation imitative of the elaborate and
lavish Baroque or the Churrigueresque style.
Mission architecture usually exhibits many of
the following characteristics: thick, massive
walls of adobe brick, laid with lime mortar
where available, commonly with wall but-
tresses to provide additional stability; adobe
wall surfaces usually coated with lime-and-
sand stucco to reduce the effects of erosion;
tamped earth floors, commonly decorated with
square tile, arcaded walkways with arches
usually built around the patios; commonly,
multicurved gables, a belfry, bell tower, or twin
bell towers; a flat roof or a low-pitched roof
with shaped parapets, usually supported by
round logs; thatched or tile roofs; grilles cover-
ing windows facing the street; a massive wood
door at the main entrance, sometimes heavily
carved or paneled, often set in an elaborately
sculptured portal. Compare with Mission
Revival; also see Spanish Colonial archi-
tecture.
mission dormer In Mission Revival architec-
ture, a dormer having a multicurved shape simi-
lar to that of a mission parapet; it projects above
the tiled roof.

635

mission parapet

mission parapet In Spanish Colonial archi-
tecture, a low, freestanding wall at the edge of a
roof (i.e., a parapet) whose upper edge has two or
more curves on each side of the uppermost
point.

Mission Revival, Mission style An archi-
tectural style popular in the southwestern
United States and in Florida from about 1890
to 1930 and beyond; suggestive or imitative of
the earlier Mission architecture, although usu-
ally much simpler because of the absence of
sculptured ornamentation; compare with
Spanish Colonial Revival. Buildings in this
style are usually characterized by: stucco-
finished exterior walls, occasionally with terra-
cotta ornamentation; balconies or balconets;
semicircular arches; a roof supported by mas-
sive piers with broad arches between them,
forming arcaded walkways; multicurved gables;
a low-pitched red mission-tile roof; often a
hipped roof; open eaves having exposed rafters
and a significant overhang; roof ridges topped
with a red-tiled protective cap; commonly,
dormers; tile-faced bell towers; roof drainage
provided by waterspouts that pierce the para-
pets; typically, double-hung rectangular win-
dows; a main entry door often located within a
recessed porch.

mission tile 1. A red-clay roofing tile, approxi-
mately semicylindrical in shape; laid in courses,
with adjacent tiles having their convex side
alternately up and down; also called Spanish tile.
2. Same as pantile, 2.

tile

mist coat A sprayed coat of very dilute paint.
miter, mitre The oblique surface forming the

beveled end or edge of a piece where a miter

joint is made.

miter arch, mitre arch Two straight blocks of
stone set diagonally over an opening, the upper
ends resting against each other.

miter arch

miter bevel A piece of material, such as wood,
usually cut at a bevel, 1 of 45°, used with a simi-
larly beveled piece to form a right-angled joint.

miter block In joinery, a wood block arranged
for sawing pieces at an angle of 45°.

miter board, miter shoot A board on which
material to be planed is laid; guides or stops hold
the material at the prescribed angle so that the
ends of the miters can be planed at the correct
angle.

miter box A device for guiding a handsaw at
the proper angle in making a miter joint; often a
narrow wooden box having a bottom and two
sides in which kerfs are cut (usually at an angle
of 45°) for guiding the saw.

miter box

miter brad Same as corrugated fastener.
miter cap, mitre cap A shaped wood block,

supported by the newel post, which receives the

mitered handrail.
miter clamp, miter cramp A clamp used to

hold together a miter joint during gluing.
miter cramp See miter clamp.
miter cut Any oblique cut across two pieces of

board or molding, so that when joined they form

an angle.

636

mixed-in-place pile

miter dovetail See secret dovetail.

mitered-and-cut string Same as cut-and-
mitered string.

mitered closer A brick closer cut at an oblique
angle.

mitered fitting A fitting especially manufac-
tured for use with beveled pipe.

mitered hip A close-cut hip.

mitered tile A piece of tile that is cut at the
appropriate angle that will finish upright work;
at the corners of dormers.

mitered valley A valley which is close-cut.

miter ending The end of a member having an
angular, dovetailed, or square member which is
designed to fit into an adjacent matching member
so as to provide a continuous profile at the joint.

miter gauge A gauge for determining the angle
of a miter.

mitering machine A machine for sawing or
cutting the ends of pieces to be joined to a true
angle of 45°, in order that they may be united by
a miter joint, or for cutting the pieces to any
desired angle to make a bevel joint.

miter joint A joint between two members at an
angle to each other; each member is cut at an
angle equal to half the angle of the junction; usu-
ally the members are at right angles to each other.

miter knee The miter joint between the hori-
zontal handrail at a stair landing and the adja-
cent angled handrail of the descending stairs.

miter plane A carpenter's plane generally used
for preparing miter joints or butt joints.

miter post A meeting post.

miter rod A flat steel plate having one end cut
at a 45° angle; used by plasterers in finishing
reentrant corners.

miter saw See tenon saw.

miter shoot See miter board.

miter square l.In carpentry, a square with a
handle having one edge with a bevel at an angle
of 45°; used for laying out miter joints. 2. A
bevel square with a blade having a fixed angle of
45° for marking miters prior to cutting.

miter valve A valve having a disk that fits in a
seat at a 45° angle to the axis of the valve.

mitre British variant of miter.

mix A ready-mixed batch of concrete, plaster, or
mortar.

MIX. On drawings, abbr. for "mixture."

mix design Same as proportioning.

mixed arch A three- or four-centered arch; a
composite arch.

mixed garden wall bond In brickwork, a
bond similar to English garden wall bond, except
that the course of headers is replaced by one
consisting of alternate headers and stretchers.

miter joint

mixed garden wall bond

miter joint with spline

mixed glue A ready-mixed synthetic resin
glue.

mixed-grained lumber Edge -grained and flat-
grained lumber in any combination.

mixed-in-place pile A soil-cement pile,
formed in place by forcing a grout mixture

637

mixed occupancy

through a hollow shaft into the ground where it
is mixed with in-place soil.
mixed occupancy In a building, two or more
classes of occupancy so intermingled that sepa-
rate safeguards for each class are impractical; the
building construction, fire protection, exit facil-
ities, and other safeguards meet the require-
ments for the most hazardous occupancy unless
otherwise specified.

mixed use 1 . Descriptive of a district that has
been zoned to permit more than a single use,
for example, commercial and residential. 2.
Descriptive of a building that has more than
one use.

mixer A machine employed for blending the
constituents of concrete, grout, mortar, or paint.

mixer efficiency The adequacy of a mixer in
rendering a homogeneous product within a
stated period; determinable by testing samples,
which are extracted from various portions of a
freshly mixed batch, for differences in physical
properties.

mixer truck See truck mixer.

mixing box l.A device used to reduce the
air velocity in the duct of a medium- or high-
pressure, high-velocity HVAC system; incorpo-
rates a valve which controls the volume of
flow for distribution of air within a room and
for mixing hot and cold air. 2. See dual-duct
system.

mixing cycle In mixing concrete in a batch
mixer, the time taken for a complete cycle, i.e.,
the elapsed time between successive discharges
of the mixer.

mixing plant See batch plant.

mixing speed In mixing a batch of concrete,
the rate of rotation of a mixer drum or of the
paddles in an open-top, pan, or trough mixer,
expressed in rpm or in feet per minute (or meters
per minute) of a point on the circumference of
the drum at its maximum diameter.

mixing time The period of time during which
the constituents of a batch of concrete are mixed
in a fixer.

mixing valve A valve which mixes liquids, by
either automatic or manual regulation.

mixing varnish A varnish which is added to a
pigmented paint to increase its gloss or improve
its sealing properties.

mixing water The water in freshly mixed
sand-cement grout, mortar, or concrete, exclu-
sive of any previously absorbed by the aggregate.

mix proportion In a given concrete mixture,
the ratio of cement to sand to gravel, in terms of
either dry, loose volume or dry weight.

Mixtec architecture A type of Mesoameri-
can architecture, circa 1000 A.D., in the state of
Oaxaca, Mexico; usually characterized by great
mass, use of interior stone columns, and empha-
sis on horizontal lines; minutely detailed fret-
work on paneled friezes; use of scapulary tablets
on building facades.

mixture l.The assembled, blended, commin-
gled ingredients of mortar, concrete, or the like.
2. The proportions for their assembly.

MK On drawings, abbr. for "mark."

ML On drawings, abbr. for "material list."

mldg, Mldg Abbr. for "molding."

MLMA Abbr. for "Metal Lath Manufacturers
Association."

mm Abbr. for "millimeter."

MN On drawings, abbr. for "main."

MO On drawings, abbr. for "month."

moat A broad, deep trench surrounding the
ramparts of a town or fortress; usually filled with
water.

mobile form Same as slipform.

mobile scaffold A portable rolling scaffold
supported by casters.

mock-up A model of an object in the course of
design, as a section of a window or its parts; built
to scale or at full size, for purposes of studying
construction details, judging appearance, and/or
testing performance.

MOD On drawings, abbr. for "model."

mode See architectural mode.

model 1 . A representation or reproduction,
usually at small scale, for purposes of study or to
illustrate construction. 2. A pattern of an item
to be reproduced, often in quantity.

model code (US) A proposed building code
that is written and published by building-official
associations (e.g., BOCA, ICBO, and SBCC);
available for adoption by states, counties, and
municipalities.

modeling, Brit, modelling Forming or shap-
ing a clay or plaster surface.

638

modulus of rigidity

moderately hydraulic lime A putty that

sets slowly, for a period up to one month.

Modern architecture A loose term applied
since the late 19th century to buildings in a
variety of styles, in which emphasis is placed
on functionalism, rationalism, and current
methods of construction, in contrast with
architectural styles based on historical prece-
dents and traditional methods of building.
This category often includes Art Deco, Art
Moderne, Bauhaus, Contemporary style, Inter-
national style, Organic architecture, Stream-
line Moderne.

Moderne An imprecise term occasionally ap-
plied to Art Moderne, PWA Moderne, Stream-
line Moderne, and Art Deco.

Moderne Style Same as Style Moderne; also
see Art Deco.

Modernismo The Spanish, particularly Cata-
lan, version of Art Nouveau.

Modernistic style See Art Deco and Art
Moderne.

modernize To adapt a building or structure to
current conditions, tastes, or usage, usually by
remodeling.

Modern style An imprecise term that often
includes Contemporary style and Shed style.

modification 1. A written amendment to the
contract document signed by both parties. 2. A
change order. 3. A written or graphic interpre-
tation issued by the architect. 4. A written order
for a minor change in the work, 1 issued by the
architect.

modified asphalt An asphalt that has been
modified by the addition of a synthetic resin or
rosin ester.

modified portland cement, type II port-
land cement A cement used in general con-
struction where moderate heat of hydration is
required.

modillion A horizontal bracket or console,
usually in the form of a scroll with acanthus,
supporting the corona under a cornice. If in
the form of a plain block, it is a block modil-
lion or uncut modillion. Found in Corinthian,
Composite, and, less frequently, Roman Ionic
orders.

modillion block See modillion.

modillion

modillion cornice A cornice supported by a
series of modillions, often found in Composite
and Corinthian orders.

modular construction 1. Construction in
which a selected unit or module, such as a box
or other subcomponent, is used repeatedly in
the aggregate construction. 2. A system of con-
struction employing large, prefabricated, mass-
produced, partially preassembled sections or
modules which are subsequently put together in
the field.

modular dwelling A manufactured home
consisting completely or in part of module, 4.

modular masonry unit A brick or block
whose nominal dimensions are based on a 4-in.
(10.16 cm) module.

modular ratio The ratio of the modulus of

elasticity of steel to that of concrete.
modular system, modular design A

method of designing or constructing buildings
and equipment in which modules are widely
used.

module l.A distinct component forming part
of an ordered system. 2. A repetitive dimen-
sional or functional unit used in planning,
recording, or constructing buildings or other
structures. 3. A standard, usually of length, by
which the proportions of a building are deter-
mined. 4. A unit of a building structure which is
based on a standard pattern of standard dimen-
sions.

modulus of elasticity In an elastic material
which has been subject to strain below its elastic
limit, the ratio of the unit stress to the corre-
sponding unit strain.

modulus of resilience The amount of elastic
energy absorbed by a unit volume of a material
when it is loaded to its elastic limit in tension.

modulus of rigidity, modulus of shear In

an elastic material which has been subjected to
stress, the ratio of the shearing stress to the
shearing strain.

639

modulus of rupture

modulus of rupture A measure of the ulti-
mate load-carrying capacity of a beam; equal to
the ratio of the bending moment at rupture to
the section modulus of the beam.

modulus of subgrade reaction Same as
coefficient of subgrade reaction.

modulus of toughness The amount of en-
ergy per unit volume which is absorbed by a
structural material when subject to shock or
impact, up to the point of fracture.

moellon Stone rubble used as filling between
the facing walls of a structure.

Mogen David See Star of David.

Mogul architecture The later phase of
Indian Islamic architecture, named after the
Mogul dynasty (1526-1707), typified by monu-
mental palaces and mosques and detailed deco-
rative work. The Taj Mahal is the most famous
example.

mogul base A large, screw-in type of base for
an incandescent lamp of 300 watts or higher.

Mohammedan architecture See Muslim
architecture, Islamic architecture.

Mohs' scale A scale which rates the scratch
hardness of a mineral on a scale of 1 (talc) to 10
(diamond).

moist room A room in which the atmosphere
is maintained at a selected temperature, usually
73.4°F (23°C), with a relative humidity of at
least 98%, for the purpose of curing and storing
cementitious test specimens.

moisture barrier l.A vapor barrier. 2. A
damp course.

moisture content l.The weight of water,
usually expressed as a percentage of the total dry
weight of a material. 2. The weight of water in a
given soil mass.

moisture equilibrium See equilibrium mois-
ture content.

moisture expansion l.See bulking. 2. An
increase in dimension or bulk volume of a mate-
rial or manufactured article caused by the
absorption of water or water vapor.

moisture gradient The difference in moisture
content between the inside and outside of a
piece of wood.

moisture migration Same as moisture move-
ment.

moisture movement 1 . The process by which
moisture moves through a porous medium, such
as a wall construction, as a result of differences in
vapor pressure. 2. The effects of such movement
on the dimensions of a material such as concrete,
mortar, cement paste, or rock.

moistureproofing The application of a mois-
ture barrier.

MOL Abbr. for maximum overall length.

mold, mould l.A concave and/or convex
form from which castings or pressings are repli-
cated. 2. A template or pattern. 3. Same as
molding.

■<.».

•fr'-

FORM CONCRETE

mold for finishing concrete

molded brick 1 . A specially shaped brick, usu-
ally for decorative work. 2. Ordinary brick
which is neither cut with a wire nor pressed.

molded-case circuit breaker A relatively
light, fast-acting electrical circuit breaker
assembled as an integral unit in a supporting
and enclosing housing of molded insulating
material.

molded insulation A thermal insulation
material that is premolded to fit the surface con-
tours of pipes, pipe fittings, valves, etc.

molded plastic skylight A skylight molded
of transparent or translucent plastic, which
allows the passage of light to the space below.

molded plywood Plywood formed and cured
into a curved shape.

molding A member of construction or decora-
tion so treated as to introduce varieties of out-
line or contour in edges or surfaces, whether on
projections or cavities, as on cornices, capitals,

640

monkeytail bolt

CROWNING

SUPPORTING
BINDING

D £> b

SEPARATING

LL^^

sections of classical moldings: A, cavetto; B, conge;

D, cyma recta; E, quarter round; F, ovolo; G, echinus;

H, cyma reversa; I, half round; J, torus; K, thumb; L, half

hollow; M, fillet; N, head; O, scotia; P, cavetto; Q, scape;

R, cyma recta; S, cyma reversa; T, ovolo

bases, door and window jambs and heads, etc.;
may be of any building material, but almost all
derive at least in part from wood prototypes (as
those in classical architecture) or stone proto-
types (as those in Gothic architecture). Mold-
ings are generally divided into three categories;
rectilinear, curved, and composite-curved. Also
called a mold. For special definitions and illus-
trations, see applied molding, beadmolding,
bead-and-reel molding, bolection molding,
cyma, dripmolding, egg-and-dart molding, half-
round molding, head molding, hip molding,
hood molding, Italian molding, label molding,
laid-on molding, ogee, ovolo molding, planted
molding, quarter-round molding, rope molding,
scotia, stop molding, struck molding, sunk mold-
ing, tongue-and-dart molding, treacle molding,
weather molding.

molding machine A high-speed machine for
planing, shaping, and cutting moldings.

molding pattern See WP-series molding pat-
tern.

molding plastic A partially polymerized resin,
usually in powdered form, which is molded
under heat and pressure; often filler materials
and pigments are added.

molding powder See molding plastic.

mold stone The jambstone of a door or win-
dow.

molecular sieve An adsorbent composed of
porous aluminosilicates with pores of uniform
molecular dimensions which will selectively
absorb molecules of the substance to be gath-
ered.

mole drain A subsurface channel for draining
water.

moler brick l.An insulation brick made
from moler earth, a type of diatomaceous mate-
rial. 2. A brick made from any diatomaceous
earth, i.e., any diatomite.

molybdate orange Bright orange pigment
consisting of mixed crystals of lead chromate,
lead molybdate, and lead sulfate; used in paint
because of its high opacity.

moment The property by which a force tends
to cause a body, to which it is applied, to rotate
about a point or line; equal in magnitude to the
product of the force and the perpendicular dis-
tance of the point from the line of action of the
force.

moment connection A rigid or semi-rigid
connection between columns and girders.

moment of inertia Of a body around an axis,
the sum of the products obtained by multiplying
each element of mass by the square of its dis-
tance from the axis.

momentum Of a moving body, the product of
the mass of the body and its velocity.

monastery A building complex of a monastic
order.

monial Same as mullion.

monitor, monitor roof A raised section of a

roof, usually straddling a ridge; has openings,

louvers, or windows along the sides to admit

light or air.
monitor skylight

raised section of a

ridge.
monk bond Similar to Flemish bond but with

two stretchers instead of one between each

header.
monkeytail The vertical scroll at the bottom

of a handrail of a stairway.
monkeytail bolt An extension flush bolt.

A skylight placed in a
roof, often straddling a

641

monkey wrench

monkey wrench A wrench having one jaw
fixed and the other jaw (which is adjusted by a
screw) movable.

ftlHHt=o

monkey wrench

monolith An architectural member (as an
obelisk, the shaft of a column, etc.) consisting of
a single stone.

monolithic 1. Shaped from a single block of
stone, as a monolithic column. 2. Composed of
monoliths. 3. Characterized by massiveness and
complete uniformity. 4. Said of concrete which
is cast in a single piece. 5. Said of a concrete
pavement or floor whose surface layer is formed
integrally with the slab below.

monolithic concrete Reinforced concrete
cast with no joints other than construction
joints.

monolithic pour A pour of concrete, all at a
single time. Also called a one-pour system.
Contrast with two-pour system.

monolithic screed Screed, 4 laid in a single
layer without joints.

monolithic surface treatment, dry shake
The treatment of the surface of unformed con-
crete by sprinkling a mixture of dry cement and
sand on it after the water has mostly disappeared
from the surface, following the strike-off; it is
then worked in by floating.

monolithic terrazzo A terrazzo topping
which has been applied directly on a specially
prepared concrete substrate; no underbed is
used.

mono lock See preassembled lock.

monomer An organic liquid having a rela-
tively low molecular weight which reacts with
itself (or other compounds of low molecular
weight) to create a solid polymer.

mono-pitched roof A pitched roof having a
single slope.

monopteron In Greek architecture, a circular
peripteral building, as a temple, having only a
single row of columns.

monopteron

monostyle 1 . Having but a single shaft; applied

to medieval pillars. 2. Having the same style of

architecture throughout.
monotower crane Same as tower crane.
monotriglyphic In the Doric order, having

one triglyph over the space between two

columns.

monotriglyphic

monstrance See ostensory.

montant That part of a framed stile which is in

contact with the rail.
Monterey style, Monterey Revival An

architectural style that came into existence in
Monterey, California, between about 1835 and
1840; typically, a two-story house with a full-
facade balcony supported by plain wood posts
and enclosed by wood railings. A modified ver-
sion of this style was revived from about 1920 to
1960, combining Spanish Colonial architecture
with some elements of early New England colo-
nial architecture; in this 20th-century version,
the balcony is typically cantilevered rather than
supported by wood columns from ground level,
as in the earlier Monterey style. Nineteenth-
century houses in this style usually were charac-
terized by: thick whitewashed adobe walls; a

642

mortar bed

Monterey style

low-pitched gable roof or hipped roof with its
ridge parallel to the facade, usually covered with
hand-split wood shingles, but sometimes with
tiles; occasionally a decorative chimney cap or
chimney hood; double-hung wood-frame win-
dows with mullions; often, window shutters;
occasionally, full-length windows opening onto
the balcony; a relatively simple paneled entry
door. Doors in 20th-century houses in this style
are often imitative of those found in Colonial
Revival architecture, including paneling, a fan-
light over the door and sidelights flanking the
door; occasionally, some elements of Greek
Revival are included in the wood trim around
doors and windows.

montmorillonite One of the common clay
minerals which typically swells upon wetting
and becomes soft and greasy.

monument l.A permanent natural or artifi-
cial object marking the corners and boundaries
of real property or establishing the location of a
triangulation or other important survey station.
2. A stone, pillar, megalith, structure, building,
or the like, erected in memory of the dead, an
event, or an action.

monumental stone A dimension stone of
adequate size and quality for use in carving a
monument or a memorial.

moon gate In traditional Chinese architecture,
a circular opening that provides a passageway
through a wall.

Moorish arch Same as horseshoe arch.

Moorish architecture The Islamic architec-
ture of North Africa and the regions of Spain
once under Islamic domination.

Moorish Revival A rarely used mode of
Exotic Revival architecture from about 1845 to

1890. Usually characterized by the use of
horseshoe arches, multifoil arches, and win-
dow tracery.

moot hall A place of public assembly; a hall for
meeting, debate, or judgment; a town hall.

mop-and-flop A roofing procedure in which
roofing elements (such as felt plies or cap sheets)
are initially placed upside down adjacent to their
ultimate locations on the substrate; then they
are coated with adhesive, turned over, and
adhered to the substrate.

mopboard A baseboard.

mopping Applying hot bitumen with a mop or
mechanical applicator on the felt of a built-up
roof membrane, on a roof-deck, or the like.

mop plate A narrow plate fixed to the bottom
of a door for protection against soiling from a
mop; similar to a kickplate.

mop sink A type of sink having a deep basin,
usually used by janitors.

mopstick handrail A handrail having a circu-
lar cross section except for a small flat on the
underside.

Moresque architecture Same as Moorish
architecture.

morgue, mortuary A room or building for
the holding and/or identification of dead bodies
prior to burial or cremation.

Mormon thatched-roof shed Same as
jacal, 1 .

morning room A family, or private, sitting
room, usually sunlit early in the day.

mortar, mortar mix A plastic mixture of
cementitious materials (such as plaster,
cement, or lime) with water and a fine aggre-
gate (such as sand); can be troweled in the
plastic state; hardens in place. When used in
masonry construction, the mixture may con-
tain masonry cement or ordinary hydraulic
cement with lime (and often other admix-
tures) to increase its plasticity and durability.
Also see clay-and-hair mortar, gypsum mortar,
lime mortar.

mortar aggregate An aggregate consisting of
natural or manufactured sand.

mortar bed l.A mortar box. 2. A thick layer
of mortar used to seat a structural member.

643

mortarboard

mortarboard, fat board, spot board A

board, usually set on legs to form a table, used to
mix lime putty and gauging plaster.

mortar box, mortar bed A shallow, trough-
like box in which mortar or plaster is mixed.

mortar brick A type of brick used primarily in
the 18th and 19th centuries; usually consisted of
a mixture of sand and lime, to which water was
added; then molded into bricks and allowed to
harden in the open air; primarily used in regions
where clay for making a better grade of bricks
was unavailable.

mortar classification A system of classifying
mortar for brickwork numerically, from 1 to 5, 1
being the strongest and 5 the weakest.

mortar cube test A test of the compressive
strength of a material; a sample is formed into a
cube, dried according to a standard procedure,
and then crushed.

mortar fillet Same as cement Met.

mortar joint See masonry joint.

mortar mill A mixing and stirring machine for
combining lime, sand, and other materials to
make mortar.

mortar mix See mortar.

mortar tray A template designed to facilitate
the laying of two ribs of mortar in conjunction
with V-brick.

mortgage A loan in which property is used as
security for the debt.

mortgagee The lender from whom a mortgage
is obtained.

mortgage lien A charge against property as
security for the payment of a loan.

mortgagor The borrower who obtains a mort-
gage.

mortice British variant of mortise.

mortise A hole, cavity, notch, slot, or recess cut
into a timber or piece of other material; usually
receives a tenon, but also has other purposes, as
to receive a lock.

mortise-and-tenon joint, mortise joint A
joint between two wood members that is formed
by fitting a tenon at the end of the one member
into a mortise in the other member; the mortise
and the tenon are usually cut or shaped with a
mallet and chisel. After fitting the tenon into
the mortise, a hole is drilled through them with

MORTISE AND
TENON

mortise-and-tenon joint

an auger; then a wooden peg (treenail) is driven
into the hole to secure the joint. Also called a
mortise-and-pegged joint.

mortise bolt A door bolt designed to be mor-
tised into a door rather than applied to its sur-
face.

mortise chisel, framing chisel, heading
chisel, socket chisel A steel chisel for
woodworking; has a heavy body with a socket
shank; esp. used for cutting mortises.

mortise chisel

mortised astragal On a door having two
leaves, a two-piece astragal having one part
recessed in the edge of each door.

mortised astragal

mortise gauge A tool (similar to a marking
gauge) having two scribes for marking parallel
lines; can be adjusted to the required distances

644

motor controller

from a working edge in preparing mortises or

tenons.
mortise joint See mortise-and-tenon joint.
mortise latch A mortise lock.

mortise lock A lock designed to be installed in
a mortise rather than applied to a door's surface.

mortise lock

mortise machine A machine which cuts
square or rectangular holes, usually with a chisel,
or circular holes with a circular cutting bit.

mortise pin A pin which locks a mortise-and-
tenon joint by being driven either through the
extended tenon or through both the mortise and
the tenon.

mortise preparation On a door or doorframe,
the drilling, tapping, and reinforcing for hard-
ware which is to be mortised into it.

mortuary See morgue.

mortuary temple A temple for offerings and
worship of a deceased person, usually a deified
king, as distinguished from a cult temple.

mosaic l.A pattern formed by inlaying small
pieces of stone, tile, glass, or enamel into a

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Slag

jag

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* f X ^** 5** '**■ X J*r !*• -^ -*

la ■ # * . » ■ m 4-4 * - *»»

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cement, mortar, or plaster matrix. 2. A form of
surface decoration, similar to marquetry, but usu-
ally employing small pieces or bits of wood to
create an inlaid design.

Moslem architecture See Muslim architec-
ture.

mosque A Muslim house of worship.

mosaic, 1

mosque

MOT On drawings, abbr. for "motor."

motel A roadside building or group of build-
ings which contains hotel and parking accom-
modations primarily for transient motorists,
often with individual exterior entrances to
each room.

motif A principal repeated element in an orna-
mental design.

motion detector A device to detect intru-
sion within an area to be protected. The device
radiates waves (electromagnetic or ultrasonic,
at a fixed frequency) that are reflected back
to the device. If an intruder moves within the
protected space, a change in frequency results
which is detected and which activates an
alarm.

motor A machine which converts electric
power into mechanical power by means of a
rotating shaft.

motor branch circuit A branch circuit
which supplies electric power to one or more
motors and their associated controllers.

motor-circuit switch A switch intended for
use in an electric-motor branch circuit; rated in
horsepower and capable of interrupting the
maximum operating overload current of a motor
of the same rating at the rated voltage.

motor controller A controller which governs
the power delivered to a motor (or group of
motors).

645

motor-generator set

motor-generator set A machine that consists
of a motor which is mechanically coupled to an
electric generator.

motor grader A dirt-moving machine for lev-
eling and planing the surface to fine tolerances
by means of a blade (or moldboard) than can be
set and held at precise slope and elevation. Con-
trols at the operator's station raise and lower,
turn, and tilt the moldboard.

motorized buggy cart A type of power-
driven wheelbarrow.

motor starter A motor controller used only for
connecting and disconnecting a motor.

motte In medieval times, a high, defensive
mound of earth surmounted by a timber stock-
ade and tower, and surrounded by a ditch.

motte-and-bailey A motte that is adjacent to,
or surrounded by a bailey; the open area within a
medieval fortification.

mottle 1. The pattern or arrangement of spots
and cloudings forming a mottled surface, esp. in
marble, or in wood veneer as a result of unusual
variation in fiber growth or fiber arrangement.
Also see fiddleback, quilted figure, blister figure.
2. See mottling.

mottler In painting, a brush having a flat thick
shape; used for graining and marbling.

mottling Spotty round marks which appear as a
defect in a sprayed film of paint.

moucharaby See meshrebeeyeh.

mouchette In 14th cent. Gothic tracery and
derivatives, a typical small motif, pointed, elon-
gated, and bounded by elliptical and ogee
curves; a dagger motif with a curved axis.

mould, moulding British variants of mold,
molding.

mouse, duck A lead weight on a string; used
to pull a sash cord over a sash pulley, to clear a
blocked pipe, etc.

mouse-tooth pattern, mouse-tooth finish
See tumbling course and straight-line gable.

movable form In the placement of concrete, a
formwork which has been so sized in its manu-
facture or construction as to be suitable for
repetitive use in a series of pours.

movable partition A demountable partition.

movement In wood, same as working.

movement joint Same as expansion joint, 1 .

moving ramp A continuously moving system
on which passengers stand, to be carried along a
horizontal plane or up an inclined plane.

moving staircase, moving stairway See
escalator.

moving walkway A continuously moving
passenger-carrying device on which passengers
stand or walk; the passenger-carrying surface
remains parallel to its direction of motion and is
uninterrupted.

mow The loft in a barn for storage of hay.

Mozarabic architecture Northern Spanish
architecture built after the 9th cent, by Chris-
tian refugees from Moorish domination, charac-
terized by the horseshoe arch and other Moorish
features.

Mozarabic style A style of architecture used
by Christians in Spain from about the 9th to the
16th century, when Spain was under Moorish
domination.

mpl Abbr. for maple.

MR Abbr. for mill run.

M-roof A roof formed by joining two parallel
gable roofs, creating a valley between them,
resembling the capital letter M in section.

M-roof

MRT Abbr. for "mean radiant temperature."

MRTR On drawings, abbr. for mortar.

MSDS Abb. for "Material Safety Data Sheet,"
used by OSHA for construction materials.

mucilage 1. An adhesive prepared from a gum
and water. 2. A liquid adhesive which has low
bonding strength.

muck 1 . An organic soil of very soft consis-
tency; also called muck soil. 2. Material to be
excavated; clay, dirt, loam, stone, etc. 3. The
material so excavated.

muck soil Same as muck, 1.

646

multicolor finish

mud A mixture of soil with sufficient water to
make it soft.

mud-and-sticks chimney Same as clay-and-
sticks chimney.

mud brick A term occasionally used for adobe
that has been shaped in a brick form and then
sun-dried.

mud-capping The blasting of a boulder by
placing a quantity of explosives against it with-
out confining the explosives in a drill hole.

Mudejar architecture A Spanish style cre-
ated by Moors under Christian domination in
the 13th and 14th cent., but retaining Islamic
elements such as the horseshoe arch.

mudflow Movement of soft weak soil having
the consistency of mud.

mud house Any primitive dwelling having
walls of unbaked earth; often constructed of
molded sun-dried blocks of mud usually mixed
with straw, manure, or other material to provide
increased mechanical strength.

mud-jacking A process of raising a concrete
slab on ground where it has settled or been
depressed; a hole is drilled through the slab, then
a mixture of mud and cement is pumped beneath
the slab under pressure, thereby raising it.

mud plaster A plaster that is usually a mixture of
heavy clay and water, often containing chopped
straw or manure to improve its mechanical
strength when dry.

mud room A small entry area in a house where
muddy footwear and wet outer clothing may be
removed and stored temporarily.

mud sill The lowest horizontal timber at the
base of a timber-framed building, usually laid
directly on the ground; used to distribute con-
centrated loads.

mud slab A layer of concrete, 2 in. (5 cm) to 6
in. (15 cm) thick, below a structural concrete
floor or footing over soft, wet soil.

mud wall A wall usually constructed of a mix-
ture of clay and a binder such as chopped straw;
often, gravel is added.

muff glass Window glass, made by a now obso-
lete technique. A glass cylinder was blown; but
before it cooled, it was sliced lengthwise and
unrolled into a flat piece from which the panes
were cut.

muffle 1 . A material used to build up the core

of a large plaster molding. 2. To deaden sound.
muffler See sound attenuator.

Mughal architecture See Mogul architec-
ture.

mulch Material such as leaves, hay, straw, or the
like, spread over the surface of the ground to
protect the roots of newly planted shrubs or
trees, of tender plants, etc., from the sun or from
the cold.

mullion A vertical member separating (and
often supporting) windows, doors, or panels set
in series. Also see door mullion.

■

irlJi 1

mullions:

mullion cover A loose piece of metal trim
which screws or snaps in place on the interior
side of the mullion of a window.

MULT On drawings, abbr. for "multiple."

multibag packer See carousel packer and lin-
ear packer.

multi-blade damper A damper, 1 through
which the quantity of airflow is controlled by
means of a number of blades linked together
mechanically.

multicentered arch An arch having a shape
composed of a series of circular arcs with differ-
ent radii, giving an approximation to an ellipse.
These arcs are symmetrically disposed about a
vertical axis and occur in odd numbers.

multicolored brick See rustic brick.

multicolor finish A speckled paint finish con-
taining small individual colored particles.

647

multiconductor cable

multiconductor cable An assemblage of sev-
eral electrical conductors having a common
outer jacket.

multicurved gable A gable having an out-
line containing two or more curves on each
side of a central ridge; for example, see Flemish
gable.

multicurved parapet At the edge of a roof, a
freestanding wall whose outline contains sev-
eral curves on its upper surface, as in a mission
parapet.

multicurved parapet

multi-element prestressing Prestressing of
reinforced concrete which is accomplished by
stressing an assembly of several individual struc-
tural elements to produce one integrated struc-
tural member.

multifamily dwelling A residential building
containing more than two dwelling units.

multifoil Having more than five foils, lobes, or
arcuate divisions.

multifoil: window

multifolding door A door composed of large
panels hung on a ceiling track; when the door is
open, the panels stack against each other and are
housed in a relatively small space.

multifuel burner A burner which can be fed
by more than one type of fuel, used either sepa-
rately or simultaneously.

multimedia filter In a water supply system, a

bed-type filter containing several different filtra-
tion media (e.g., coal, sand, and garnet).

TREATED

WATER

0UTL5T

multifoil: arch

multimedia filter

multi-outlet assembly A metallic or non-
metallic assembly used in electric wiring; a type
of surface-mounted or flush raceway designed to
hold conductors and attachment plug recepta-
cles; assembled in the field or at the factory.

multiple dwelling A building for residential
use which houses several separate family units,
usually three or more.

multiple echo See flutter echo.

multiple-family Said of a building in which
more than two families or households live

648

muntin

independently of each other and do cooking

within their own living quarters.
multiple-folding rule A folding rule up to 8 ft

long used where precision accuracy is not required.
multiple frame A framework of beams and

columns extending over more than one bay in a

horizontal direction.

multiple glazing Glazing comprised of more
two or more sheets of glass with space between
them, e.g., see double glazing.

multiple hoistway A hoistway for more than
a single elevator or dumbwaiter.

multiple-layer adhesive A film-type adhe-
sive inserted between dissimilar materials in
order to bond them together; often a different
type of adhesive is used on each side of the film.

multiple-layer weld A weld in which more
than one pass or deposit of filler metal is required
to obtain the required dimensions of the weld.

multiple of direct personnel expense A

method of compensation for professional ser-
vices based on the direct expense of professional
and technical personnel, including cost of
salaries and mandatory and customary benefits,
multiplied by an agreed factor.

multiple prime contract A contract in
which more than one primary contractor has
been retained to work on the same project.

multiple-window operator See mechanical
operator.

multiplier The factor by which an architect's
direct personnel expense is multiplied to deter-
mine compensation for his professional services
or designated portions thereof.

multi-ply construction Laminated construc-
tion having more than three plies. Also see bal-
anced construction.

multistage stressing The prestressing of rein-
forced concrete performed in stages as the con-
struction progresses.

multistory Having several stories, usually more
than five.

multistory frame, skeleton construction
A building framework of more than one story in
which loads are carried to the ground by a system
of beams and columns.

multi-unit wall A masonry wall composed of
two or more withes.

multivallate A fort on a hill that is protected
by three or more concentric ditches and
embankments.

multiway deflection The deflection of air,
from an air outlet, in several directions, usually
at 90° to each other.

multizone system An air-conditioning system
which is capable of handling several individually
controlled zones simultaneously.

municipality A town, city, or district possess-
ing corporate jurisdiction.

municipal planning See city planning and
community planning.

muniment house, (Brit.) muniment room
A secure structure or area for storing and dis-
playing important documents, official seals, etc.

munnion 1. A mullion. 2. A muntin.

muntin 1 . A secondary framing member to
hold panes within a window, window wall, or

muntin, 1

muntin, 2

649

munton

glazed door; also called a glazing bar, sash bar,
window bar, or division bar. 2. An intermediate
vertical member that divides the panels of a
door. Also see curved muntin.

munton Same as mullion.

Muntz metal, malleable brass, (Brit.) yellow
metal A copper-zinc metal alloy having 60%
copper and 40% zinc; used in castings and in
extruded, rolled, and stamped products.

muqarnas, honeycomb work, stalactite
■work An original Islamic design involving
various combinations of three-dimensional shapes,
corbeling, etc.

muqarnas

mural 1. Pertaining to a wall. 2. A mural paint-
ing, decorative or figurative.

mural arch An arch in a wall which was con-
structed in the plane of the meridian; used for
attachment of astronomical instruments in the
Middle Ages.

mural tower In a medieval fortification, one of
a number of towers built along a curtain wall, 2.

murder hole An opening in an overhanging
medieval defensive structure through which

boiling water, boiling oil, or rocks could be
dropped on an attacker; also called a machico-
lation.

murtriere Same as murder hole.

murus A wall of stone or brick, built as a
defense and fortification around an ancient
Roman town. Also see paries.

murus coctilis A wall built of bricks that have

been hardened in a kiln at an especially elevated

temperature.
museum An institution for the assembly and

public display of any kind of collection, esp. one

of rare and/or educational value.

mushrabiya See meshrebeeyeh.

mushrebeeyeh Same as meshrebeeyeh.

mushroom column In reinforced concrete
construction, a structural column, suggestive of
a mushroom shape, that flares at the top to
counteract sheering stresses.

mushroom construction A type of flat slab
construction which utilizes column capitals and
drop panels.

mushroom light A lighting fixture having
light bulbs that are located on the underside of
a mushroom-like fixture set at ground level;
especially used to illuminate a path so that
bulbs are not visible to a person walking along
the path.

mushy concrete A concrete of relatively fluid
consistency; used where mobility after initial
placement is important, as between narrowly
spaced forms or where reinforcement is closely
spaced.

musicians' gallery At the west end of a

church in Europe during the 18th century, a
gallery on which villagers played church music.

musivum Same as opus musivum.

musket-stock post A principal vertical struc-
tural support, in an early timber-framed house,
having the shape of an inverted musket stock;
the additional thickness at the top provides an
added bearing surface to support the imposed
load.

Muslim architecture, Muhammadan archi-
tecture, Saracenic architecture Archi-
tecture developed from the 7th to the 16th cent.
A.D., in the wake of the Muhammadan conquests
of Syria and Egypt, Mesopotamia and Iran, North

650

mynchery

musket-stock post

Africa and Spain, Central Asia and India, coun-
tries from which it absorbed in turn elements of art
and architecture. A new building type was devel-
oped from the Christian basilica — the multiaisled,
arcaded, columnar, or pillared mosque; a new type
of domed mosque, tomb, or madrasah from the
vaulted, centrally organized Byzantine and Sassan-
ian structures. Uses many variations of basic archi-
tectural elements; pointed, horseshoe, "Persian,"
multifoil, and interlacing arches; bulbous, ribbed,
conical, and melon domes; tunnel, cross-rib, and
stalactite vaults; a wide variety of crenelations.
Surfaces are covered by abundant geometric,
floral, and calligraphic decorations executed in
stone, brick, stucco, wood, and glazed tile.

mute A mortised rubber silencer for a door.

mutule A sloping flat block on the soffit of the
Doric cornice, usually decorated with rows of six

mutule

guttae each; occurs over each triglyph and each
metope of the frieze.

Mycenaean architecture Architecture of
the heroic age in southern Greece from the 17 th
to 13th century B.C. Exemplified in the earliest
phase by shaft graves cut into the sloping rock,
with sidewalls of stone masonry and a timber
roof; in the middle period by monumental bee-
hive tombs constructed of superimposed layers
of enormous stone blocks progressively project-
ing to create a parabolic corbeled vault, with
a stone-faced, inclined access passage leading to
the entrance composed of upward-slanting
jambs and a heavy stone lintel supporting
a characteristic Mycenaean relief triangle; in the
late period by fortified palaces having Cyclo-
pean walls, underground passages with corbeled
vaults, postern gates, and cisterns, laid out on an
irregular ground plan, with distinctive propy-
laea, one or more unconnected columnar halls
with porches facing individual courts, and long
corridors linking auxiliary and storage rooms.

mynchery Old Anglo-Saxon term for nunnery.

651

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N 1. On drawings, abbr. for "north." 2. On draw-
ings, abbr. for nail. 3. Symbol for newton.

N1E In the lumber industry, abbr. for "nosed
one edge."

N2E In the lumber industry, abbr. for "nosed
two edges."

NAAMM Abbr. for "National Association of
Architectural Metal Manufacturers."

nab The strike plate of a door lock.

nail A straight, small, rigid, slender shaft of
metal, one end of which is usually pointed; the
other end has a head that may be driven with a
hammer; used as a fastener to join separate
pieces of wood, to attach tiles to a wood sheath-
ing on a roof, and so on. Nails were hand-
wrought until the invention of machines for
their manufacture in the early 19th century. See
cut nail, dog nail, hand-wrought nail, wire nail,
wrought nail.

FINISH NAIL

w&&

CASING NAIL

SPIKE (LARGER THAN 60d]

OUPLEX HEAP HAIL

Types of nails

nailable concrete Concrete into which nails

can be driven; usually made with a suitable light-
weight aggregate, with or without the addition
of sawdust.

nail claw A tapered steel bar having a curved
end which is slotted; generally used to pull nails
from materials, such as wood, into which they
had been driven. Also called a claw bar, nail bar,
nail puller, pinch bar, pry bar, ripping bar,
wrecking bar.

nailer Same as nailing strip.

nailer joist Same as nailing joist.

nail float See devil float.

nail gun A compressed-air device for driving
nails.

nailhead l.An ornament, often highly deco-
rated, resembling the head of a nail. 2. The
enlarged top of a nail.

decorative nailhead on a wooden quatrefoil

nailhead molding A molding decorated with
a series of quadrangular pyramidal projections
resembling the heads of nails.

nailhead molding

653

nailing

nailing In roofing, the process of fixing roofing
materials to the substrate. In exposed nailing,
the nails are left exposed to the weather. In con-
cealed nailing, the nails are protected by the
next sheet of roofing material.

nailing anchor See wood stud anchor.

nailing block A wood brick.

nailing ground A ground to which trim can
be nailed.

nailing joist A steel joist which has a nailing
strip permanently attached to it.

nailing marker A small mark cut into one
member to position a nail for correct entry into
a second wood member.

nailing strip A wood strip, attached to a sur-
face; used as a base for nailing or fastening
another material.

nail plate A metal plate which is placed over
the two ends of pieces of wood that are to be
joined (in the same plane); it is secured to each
end by screws or nails driven into the wood
through holes in the plate.

nail puller Same as nail claw.

nail punch Same as nail set.

nail set A short steel rod, usually tapered; used
to drive a nail or brad below, or flush with, a
wood surface.

nail set

nail shank The main body of a nail; the shaft
between the head of the nail at one end and the
point of the nail at the other end.

naked flooring The timber or framework on
which floor boarding is laid.

naked wall A wall with lath in place, ready for
plastering.

nanometer A unit of length used to express
wavelengths of light in and near the visible spec-
trum; 1 nanometer equals 10~ 9 meter or 10
angstroms. Abbr. nm.

naos See cella.

nap The relatively short fuzzy ends of fibers
forming the surface of the carpet.

naphtha A distillate of petroleum or coal; gen-
erally has low solvency and high volatility; used
as a solvent in paints and varnishes.

naphthenate A drier used in paints; made with
naphthenic acid and lead, cobalt, calcium, or
manganese salt.

napkin pattern Same as linenfold.

Naples yellow, antimony yellow A light
yellow pigment; the true pigment is a basic anti-
monate of lead, but is imitated by mixtures.

narrow-light door A door having a narrow
rectangular fixed light, usually placed in a verti-
cal position near the lock stile.

narrow-ringed, close-grained, close-grown,
fine-grained, slow-grown Descriptive of
wood having narrow annual rings.

narrow side Of a door, the face of a door which

contacts the doorframe stops.
narthex An enclosed porch or vestibule at the

entrance to some early Christian churches.
NAT On drawings, abbr. for "natural."
natatorium 1 . A swimming pool. 2 . A building

containing a swimming pool.

National Building Code See BOCA National
Building Code and Uniform Building Code.

National Electrical Code A nationally
accepted guide to the safe installation of wiring
and equipment; not intended as a design speci-
fication but rather for the practical safeguard-
ing of persons and of buildings and their
contents from hazards arising from the use of
electricity for heat, light, power, and other pur-
poses. Provides rules, recommended by the
National Fire Protection Association, govern-
ing the installation of interior electric wiring.
These rules, subject to revision every three
years, a standard of the National Board of Fire
Underwriters, have been incorporated in many
municipal ordinances; city or state regulations
take precedence where they differ from the
rules of the Code.

National Electrical Manufacturers Asso-
ciation A trade association of electrical man-
ufacturers setting standards of construction
quality and dimensional uniformity.

654

natural environment

National Electrical Safety Code (NESC)

Rules, prepared by the NESC and approved by
ANSI, which govern: (a) methods of grounding;
(b) installation and maintenance of electric-
supply stations and equipment, of overhead
supply and communication lines, and of under-
ground and electric-supply and communications
lines; and (c) operation of electric-supply and
communication lines and equipment.

National Fire Protection Association An
organization devoted to all aspects of fire safety.

National Historic Landmark See landmark.

National Register of Historic Places A US
government organization that maintains lists and
files of documentation of buildings, structures,
objects, districts, and sites of national, state, or
local significance. Buildings on the Register may
be marked with plaques that provide historical
information about them. Also called the
National Register. Address: National Park Ser-
vice, US Department of the Interior, RO. Box
37127, Washington, DC 20013-7127.

National style A term sometimes used as a syn-
onym for Greek Revival style during the height
of its popularity, from about 1830 to 1850.

National Trust for Historic Preservation
A national, nonprofit private organization char-
tered by the US Congress to encourage public
participation in the preservation of buildings,
objects, and sites that have been significant in
American history. Address: 1785 Massachusetts
Avenue, NW, Washington, DC 20036.

native asphalt Same as natural asphalt.

natte A basket weave, as a pattern carved or
painted to imitate interlaced withes, 2 of matting.

natural asphalt Asphalt occurring in nature,
produced from petroleum by natural evaporation
or distillation; usually not suitable for paving
purposes until refined and softened to proper
consistency by combining with flux oil.

natural bed Of a stone, a plane parallel to its
natural strata.

natural cement A product obtained by finely
pulverizing calcined argillaceous limestone
which has been burnt at a temperature no higher
than necessary to drive off carbon dioxide.

natural circulation The circulation of air or
water due to differences in density rather than to
the actions of a pump or blower.

natural clay tile A ceramic tile made from
clays that produce a dense body, having a dis-
tinctive, slightly textured appearance.

natural-cleft Describing stone that has been
split (cleaved) parallel to its stratification, yield-
ing an irregular but nearly flat surface.

natural cleft finish The finish of metamor-
phic rock (such as slate or quartzite) resulting
from cleaving it along its bedding plane.

natural convection The convection resulting
from the flow of air caused by temperature differ-
ences in an enclosed space, as opposed to the
flow of air caused by a fan. Also known as free
convection.

natural draft The flow of gases in a chimney
due to the difference in temperature and density
between the gases within the chimney and the
outside air.

natural-draft boiler A boiler system in which
a chimney is required to draw the products of
combustion through the boiler or furnace.

natural-draft chimney A chimney that draws
the gases and smoke of combustion from a furnace
because of the natural draft it develops; operates
without auxiliary mechanical-draft equipment.

natural environment The aggregate of the
natural external surroundings and conditions, in
contrast to the built environment (i.e., those
surroundings and conditions resulting from con-
struction by human beings).

655

natural fiber

natural fiber Any fiber made from a mineral,
plant, or animal source, as opposed to a syn-
thetic fiber.

natural finish Any finish resulting from the
application of a transparent substance (such as a
varnish, water-repellent preservative, sealer, or
oil) which does not affect significantly the origi-
nal color or grain.

natural finish tile Ceramic facing tile having
unglazed or uncoated surfaces which have been
fired to the natural color of the material used in
forming the body of the tile.

natural foundation A foundation which
requires no special preparation of the soil
below to support the structure.

natural frequency One of a number of fre-
quencies at which a system or object tends to
vibrate if subject to a mechanical displacement
or impact and then allowed to vibrate freely.

natural gas A combustible hydrocarbon gas
having a calorific value of about 1000 Btu per
cubic foot (8,900 kilocalories per cubic meter) of
gas; the most commonly available gas from util-
ity companies.

natural grade The elevation of the original or
undisturbed natural surface of the ground.

natural light Daytime light from the sun and
sky, as opposed to light from artificial sources.

natural pigment See earth pigment.

natural pozzolan A raw or calcined natural

material (such as volcanic ash) which has poz-

zolanic properties.
natural resin A solid, thermoplastic organic

substance which occurs in nature; is flammable

and a nonconductor of electricity.

natural sand Sand which is the result of nat-
ural disintegration and abrasion of rock.

natural-seasoned lumber See air-dried lum-
ber.

natural stone True stone, as distinguished
from imitations. The term is a redundancy, as
stone is, by definition, natural in its occurrence.

natural ventilation Ventilation by air move-
ment caused by natural forces, rather than by
fans.

naval stores l.Oils, resins, tars, and pitches
obtained from the oleoresin of pine trees. 2.
Obsolete name for resin and turpentine.

nave l.The middle aisle of a church. 2. By
extension, both middle and side aisles of a
church from the entrance to the crossing or
chancel. 3. That part of the church intended
primarily for the laity.

NAVE

NAVE
ARCADE

nave, 1; nave arcade

nave arcade The open arcade between the
central and side aisles.

NBC Abbr. for "National Building Code."

NBFU Abbr. for "National Board of Fire
Underwriters."

NBS l.Abbr. for "National Bureau of Stan-
dards." 2. Abbr. for "natural black slate." 3.
Abbr. for "New British Standard."

NC Abbr. for "noise criterion."

NC curves A series of curves of octave-band
sound spectra, used to provide a single-number
rating of the noisiness of an indoor space. A
measured octave-band spectrum is compared
with this set of curves to determine the NC level
of the space in which the measurements were
made.

656

needle

NCM On drawings, abbr. for "noncorrosive

metal."
NCMA (US) Abbr. for the "National Concrete

Masonry Association."
NCSBCS Abbr. for the "National Conference

of States on Building Codes and Standards."
neat Descriptive of plaster or cement mixed

without the addition of any material except

water. See neat cement.
neat cement 1. Hydraulic cement in the unhy-

drated state. 2. Cement mortar made without the

addition of sand.
neat cement grout l.A fluid mixture of

hydraulic cement and water, with or without

admixture. 2. The hardened equivalent of such

mixture.
neat cement paste A mixture of hydraulic

cement and water, both before and after setting

and hardening.
neat gypsum plaster See gypsum neat plas-
ter.

neat line, net line 1 . A line which defines the
limits of work, such as an excavation, cut stone,
etc. 2. The true face line of a building regardless
of the projections of the stones; a line back of, or
inside of, incidental projections.

neat plaster Plaster made without aggregate.

neat size The exact size after preparation.

neat 'work Brickwork set at the base of a wall
above the footings.

nebule molding, nebuly molding A char-
acteristic Norman molding with an undulating
lower edge.

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L -■!■<(' — .- - ■■ — ! — jj i ■ . I ..: |

nebule molding

NEC

Abbr. for National Electrical Code.

necessarium A privy in an ancient castle or a
monastery.

neck 1. In the classical orders, the space between
the bottom of the capital and the top of the shaft,
which is marked by a sinkage or a ring of mold-
ings. 2. A section of the branch duct that con-
nects an air diffuser with the main supply duct.

necking l.Same as neck. 2. A molding or
group of moldings between a column and capi-
tal. 3. Any ornamental band at the lower part of
a capital; a hypotrachelium. 4. An irrecoverable
reduction in cross section of a sealant under
stress.

ASTRAGAL

necking, 2

neck molding A necking which takes the form
of a molding of any type; same as necking, 2.

necropolis l.A city of the dead; a large ceme-
tery in ancient Egypt, Greece, Phoenicia,
Carthage, etc. 2. An ancient or historic burial
place.

necropolis of Tantalus, Sipylus; section (above)
and plan (below)

needle l.A piece of timber laid horizontally
and supported on props or shores under a wall or
building, etc.; provides temporary support while
the foundation or part beneath is altered,
repaired, or underpinned. 2. A short timber, or
the like, which passes through a hole in a wall;
used to support a shore, a scaffold, etc.

657

needle bath

needle bath A shower bath containing pipes
with a large number of tiny holes through which
a spray of water strikes the bather in tiny jets.

needle beam A crossbeam supporting a load;
used in underpinning foundation walls; attached
to columns at its ends, clear of the existing footing.

needle beam scaffold Same as needle scaf-
fold.

needle pile A very slender steel pile used in
underpinning operations.

needle scaffold A scaffold which is hung from
needles.

needle spire A slender spire surmounting the
center of a tower roof.

needle valve A type of globe valve in which
the throttling is performed by a tapered pin
moving in and out of a conical seat to adjust the
fluid flow.

needlework A form of construction combin-
ing a framework of timber and a plaster or
masonry filling; common in medieval houses.

needling 1. Attaching a base coat of thatch
onto the battens of a thatched roof; by sewing
them together with a large, flat metal needle. 2.
A needle beam which provides temporary sup-
port of a load.

NEG On drawings, abbr. for "negative."

negative bending moment A bending
moment that produces compression on the bot-
tom side of a beam and tension on the top side.

negative easement An easement, 1 which
limits the possible use that the owner of land
may otherwise be entitled to.

negative friction In foundation engineering,
the additional load on a pile resulting from the
settling of fill, which tends to drag the pile
downward into the soil.

negative pressure A pressure less than atmos-
pheric.

negative- slump concrete Concrete whose
consistency has a zero slump before and after the
addition of water.

negative tension reinforcement On the

top face of a beam or slab, the tension reinforce-
ment that resists the negative bending moment.

negligence Failure to exercise that degree of
care which a reasonable and prudent person
would exercise under the same circumstances.

negotiated contract A building contract in
which the amount of the contract sum is estab-
lished by agreement between the owner and the
contractor, rather than by putting the work out
to bid.

negotiation phase See bidding or negotiation
phase.

NEMA Abbr. for National Electrical Manufac-
turers Association.

Neo-Adamesque style See Neo-Federal style.

Neo-Baroque Said of a mode of architecture
(in the late 19th century and early 20th century)
more or less patterned after Baroque architec-
ture developed in the 17th century.

Neo-Byzantine Same as Byzantine Revival.

Neoclassical Revival A mode of architecture
primarily since about 1965; a rather free interpre-
tation of the Neoclassical style with little attempt
to emulate the original style accurately; usually has
a pedimented portico with full-height columns.

Neoclassical style An architectural style based
primarily on the use of forms of Classical antiq-
uity used in both public buildings and opulent
homes; aspects of this style are imitative of the
earlier Classical Revival style (often called "Early
Classical Revival") that was most popular from
about 1770 to 1830; others are imitative of the
Greek Revival style that was popular from about
1830 to 1850. Buildings in this style are generally
characterized by: a smooth ashlar facade, an attic
story, an enriched entablature, and a parapet;
a symmetrical facade, commonly having a visually
important full-width portico with full-height wood
or stone classical columns or with square columns
(sometimes paired) and full-height pilasters, or a
one-story-high portico; an unadorned roof line;
often a side-gabled roof, hipped roof, or gambrel
roof; a moderate overhang at the eaves or boxed
eaves; balustrades frequently located just above
the eaves; commonly ornamented with statuary; a
wide frieze below the cornice; double-hung, sym-
metrically arranged, with lintels above the
windows; in homes, usually six-over-six or nine-
over-nine double-hung windows; a doorway at
the center of the facade, capped with a decorative
lintel or with a broken pediment; ornamental ele-
ments usually surround the door. The terms
Classical Revival, Neoclassical Revival, and Neo-
classicism are sometimes used as synonyms for the
Neoclassical style.

658

neon lamp

Neoclassicism A reinterpretation of the princi-
ples of Classical architecture in the late 1 8th and
the early 19th century, and beyond. This term
often includes the Federal style, Classical Revival
style, and Greek Revival style and is generally
characterized by: monumentality, colossal porti-
cos, and columns; strict use of the Greek and
Roman orders; sparing application of ornamenta-
tion, an unadorned roof line, and an avoidance of
moldings. The term Neoclassical style is occa-
sionally used as a synonym.

Neoclassicism of the 19th cent.

Neo-Colonial architecture In American
architecture of the last half of the 20th cen-
tury, a term applied to buildings more or less
patterned after 19th-century Colonial Revival
architecture but usually a poorer version of
the original; occasionally called Neo-Colonial
Revival.

Neo-Eclectic architecture One of any num-
ber of domestic modes of architecture during the
second half of the 20th century that freely bor-
rows from, but does not copy, an earlier tradi-
tional style and detailing, making little effort to
be precise in imitating its prototype; some fea-
tures of Post-Modern architecture can be called
Neo-Eclectic. For examples, see Neo-Classical
Revival, Neo-Colonial architecture, Neo-
French, Neo-Mansard, Mediterranean Revival,
Neo-Tudor architecture, Neo-Victorian.

Neo-Federal style An inexact term applied to
architecture loosely based on the American Fed-
eral style of architecture; moderately popular in
the 1920s and beyond.

Neo-French architecture A free interpreta-
tion of French Eclectic architecture in the latter
part of the 20th century (especially in America,
but also elsewhere), often vaguely recalling
farmhouses in Normandy. Usually characterized
by: steeply pitched, hipped roofs, sometimes
with flared eaves; a cylindrical tower with a con-
ical roof; occasionally, false half-timbering;
often, rounded or segmental arches over the
windows that extend above the line of the eaves.

Neo»Georgian A loose term, descriptive of
an architecture that emulates features and
details of Georgian architecture, including a
symmetrical facade, but commonly historically
inaccurate; found primarily in the 19th and
20th centuries, but continues to be built today.

Neo- Gothic The reuse of forms of Gothic
architecture in the second half of the 19th cen-
tury and thereafter.

Neo-Grec A term descriptive of architecture, pri-
marily in the 1870s, that sought to follow the tra-
beated, rectangular construction of the early
Greeks (see Greek Revival); especially usually
characterized by the use of brickwork and ironwork.

Neo-Greek Revival A term for architecture
loosely based on the Greek Revival style, usually
historically inaccurate.

Neo-Hispanic See Spanish Colonial Revival.

Neo-Liberty A mid- 1900 emulation of Art
Nouveau.

Neo-Mansard A loose term applied to archi-
tecture since about 1960 that makes use of some
form of mansard roof, but usually has little else
in common with the Mansard style.

Neo -Mediterranean See Mediterranean Re-
vival.

neon An inert gas which produces a reddish orange
glow when used in an electric discharge lamp.

neon lamp l.A cold-cathode lamp whose
principal light radiation is due to passage of an
electric current through neon gas. 2. Any cold-
cathode glass-tubing lamp, such as that used for
electric signs, regardless of the type of gas that
fills the lamp or the presence of phosphors or fil-
ters to control color.

659

Neo-Norman

Neo-Norman A style of architecture that
emulates works of the 11th and 12 th century
Romanesque in Britain and Norman France.

neoprene A synthetic rubber which has high
resistance to sunlight and oil; used in sheet form
as roof membranes and flashings, as gasketing, in
vibration control, etc.

Neo-Rococo A style of architecture that
reflects the transitional period from the Rococo
to the Classical Revival style.

Neo-Romanesque A term sometimes used as
a synonym for Richardsonian Romanesque style,
particularly in its early phases, or for Roman-
esque Revival. Also see Rundbogenstil.

Neo-Tudor Descriptive of a Neo-Eclectic
architecture, vaguely imitative of its earlier
Tudor architecture and Tudor Revival proto-
types. Houses are usually one or two stories with
front-facing gables, and generally usually char-
acterized by: false half-timbering and strapwork
employed as decorative elements; masonry or
stucco walls on the ground floor, sometimes with
a different treatment on the walls of the floor
above; occasionally, an overhanging upper story;
a shingle-covered, steeply pitched roof; promi-
nent chimney stacks; groups of tall, narrow win-
dows separated by mullions, often set with small
panes of leaded glass that are either diamond-
shaped or square -shaped, set diagonally.

Neo-Victorian A term descriptive of a Neo-
Eclectic architecture somewhat imitative of fea-
tures and details of the traditional 19th-century
Queen Anne style, 2; especially usually charac-
terized by porches of wood construction having
wood brackets and abundant spindlework.

NEPA Abbr. for "National Environmental Pol-
icy Act."

nerve Same as nervure.

nervure Any one of the ribs of a groined vault,
but esp. a rib which forms one of the sides of a
compartment of the groining.

NESC Abbr. for "National Electrical Safety
Code."

net cross-sectional area In masonry units, the
gross cross-sectional area of a section minus the
average area of ungrouted cores or cellular spaces.

net cut In an excavation on a hillside (in a par-
ticular area), the required cut minus the required
fill.

net fill In an excavation on a hillside (in a par-
ticular area), the required fill minus the required
cut.

net floor area The total usable floor area in a
building, measured to the inside of the enclosing
walls.

net line See neat line.

net load In a heating system, the gross load
minus all losses between the source of heat and
the terminal heating units (such as radiators).

net mixing water See mixing water.

net positive suction head The absolute
pressure available at the inlet to a pump; the
most important factor in determining the perfor-
mance of a pump.

net room area The wall-to-wall floor area of a
room.

net section The net or available area of a cross
section of a beam after deducting for holes for
rivets, bolts, etc.

net site area The total area which is within the
property lines of a project, but not including any
streets which may be included within.

net tensile strain The tensile strain at nomi-
nal strength, exclusive of strains due to effective
prestress, creep, shrinkage, and/or temperature.

net tracery Tracery with repetitive motifs or
openings.

net tracery

net vault A vault, 1 whose ribs form a repeti-
tive motif or a network of diamond frets.

660

New England connected barn

network 1 . An aggregate of interconnected elec-
tric conductors consisting of high- voltage feeders,
step-down transformers, protective devices,
mains, and services. 2. In CPM terminology, the
same as arrow diagram.

neutral axis An imaginary line in a beam,
shaft, or other member, subjected to bending,
where there is no tension or compression and
where no deformation takes place.

neutral conductor l.In an electric circuit
consisting of three or more conductors, the elec-
tric conductor that usually is so energized that the
voltages between it and the other conductors are
equal in magnitude. 2. In a three-phase three-
wire electrical circuit: a conductor whose poten-
tial differences between it and each of the other
conductors are equal in magnitude and equally
spaced in phase.

neutralizing The treatment of concrete,
cement, or plaster with solutions of weak acid
salts to neutralize the lime before painting.

neutral plane See neutral surface.

neutral soil Soil which is in the range from
slightly acid to slightly alkaline, usually considered
to be in the range of pH values from 6.6 to 7.3.

neutral surface, neutral plane An imagi-
nary surface within a beam, subjected to bend-
ing, where there is neither compression nor
elongation.

New Brutalism See Brutalism.

newel l.The central post or column around
which the steps of a circular staircase wind, and

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which provides support for the staircase. 2. A
newel-post.

newel cap The terminal feature of a newel-
post; often molded, turned, or carved in a deco-
rative shape.

newel collar A turned wood collar used to
lengthen the base of a newel.

newel drop An ornamental, terminal projec-
tion of a newel-post, often through a soffit.

newel joint The joint between a newel-post
and the handrail or between the newel-post and
the string of a stair.

newel-post A tall and more or less ornamental
post at the head or foot of a stair, supporting the
handrail.

newel, 1

newel-post: N

newel stair l.A screw stair. 2. Same as solid
newel stair.

New England Colonial architecture See
Cape house, captain's house, Corporate style,
meeting house, New England gambrel roof, Sab-
bath house, saltbox house, stone-ender, whale
house.

New England connected barn See contin-
uous house.

661

New England gambrel roof

New England gambrel roof A gambrel roof

in which the upper and lower slopes are of
approximately equal length; the lower slope has
a steeper pitch, usually about 60 degrees.

New England method See pick and dip.

New Shingle style A term occasionally used
to classify a late-20th-century wood-shingled
house having many of the basic characteristics of
a Shingle style house built between about 1880
and 1900.

newton (N) The unit of force in the Interna-
tional System of Units; the force necessary to
produce an acceleration of 1 metre per second-
square in a body having a mass of 1 kilogram.

new town A new, essentially self-sufficient city,
built in a previously undeveloped area, which
provides residential, commercial, industrial, edu-
cational, recreational, and public facilities.

new 'wood Virgin wood, never having been
worked by a tool.

New York leveling rod A two-piece leveling
rod with a movable target.

NFC Abbr. for "National Fire Code."

NFPA Abbr. for the National Fire Protection
Association.

NFS A Abbr. for "National Fire Sprinkler Asso-
ciation."

NGR stain, non-grain-raising stain One
of many liquid wood stains, based on alcohol or
other solvent; almost totally free of water.

nib Any projecting piece, part, or particle.

nibbed tile A roofing tile having a small pro-
jection at its head for convenience in hanging
the tile on a batten.

nib guide A straight piece of wood, nailed on
the base-coat plaster of the ceiling, which acts as
a guide on which a cornice mold is run.

NIC Abbr. for "not in the contract."

niche A recess in a wall, usually to contain
sculpture or an urn; often semicircular in plan,
surmounted by a half dome.

nicked-bit finish A stone surface having paral-
lel, raised projections of various sizes and spacing
formed by an irregularly notched planer blade.

nickel A silver-white metal; widely used as an
additive to steel and cast-iron alloys; also used in
electroplating metals which require resistance to
corrosion.

nickel steel Steel containing 3 to 5% nickel
and 0.2 to 0.5% carbon; the nickel increases the
strength and the elastic limit of the alloy; has
better properties (such as greater strength, more
ductility, and higher corrosion resistance) than
carbon steel.

nidge, nig In masonry, to dress the face of a
stone with a sharply pointed hammer instead of
a chisel and a mallet.

nidged ashlar, nigged ashlar Stone dressed
on the surface with a pick or sharp-pointed
hammer.

nig Same as nidge.

nigged ashlar See nidged ashlar.

night latch, night bolt, night lock An aux-
iliary lock having a spring latch bolt which func-
tions independently of the regular lock of the
door; may be opened by a knob or handle from
the inside but only by a key from the outside.

night stair A stair in the transept of a church
used by monks going from their dormitory to the
church for night services.

night vent See ventlight.

nimbus A halo or disk of light surrounding the
head in representations of divine and sacred per-
sonages.

662

nominal diameter

nine-over-nine A term descriptive of a dou-
ble-hung window having nine panes in the
upper sash and nine panes in the lower sash.

NIOSH Abbr. for "National Institute of Occu-
pational Safety and Health."

nippers A form of hand pincers with cutting
jaws that meet parallel to each other rather than
at an angle; used for cutting wire, thin metal
rods, or the like.

nippers

nipple A short length of pipe with threads at
each end; used to join couplings or fittings.

won

nipple

Nissen hut A semicylindrically shaped prefab-
ricated building of corrugated steel, usually ther-
mally insulated.

NIST Abbr. for "National Institute of Standards
and Technology," the successor to the US
National Bureau of Standards.

nit A unit of luminance equal to 1 candela per
square meter. Abbr. nt.

nitrile rubber A synthetic rubber which has
good resistance to oils and solvents; produced by
copolymerizing butadiene and acrylonitrile.

nitrocellulose See cellulose nitrate.

NLMA Abbr. for "National Lumber Manufac-
turers Association."

nm Abbr. for nanometer.

NO. On drawings, abbr. for "number."

nobble To shape stone roughly, usually at the
quarry.

nodding ogee arch An ogee arch containing
the statue of a saint whose head bends slightly
downward from the plane of the wall, so that it
looks down toward a viewer on the floor rather
than straight across to the opposite wall.

node l.In electric wiring, a junction point at
which several distribution or wiring conductors
come together. 2. A panel point.

nodus In ancient Roman construction, a key-
stone, or a boss in vaulting.

noel An old English term for newel.

no-fines concrete A concrete which contains
little or no fine aggregate.

nog A brick-shaped piece of wood inserted in an
internal masonry wall; often, one of a number of
such pieces; also called a wood brick.

nogging The infilling, such as between the
logs in a log cabin or between the framing
members of a timber-framed house; used to
increase the rigidity of the framing system, pro-
vide increased thermal insulation, and improve
fire resistance.

nogging piece A horizontal timber fitted
between the quarters of brick nogging and nailed
to them in order to strengthen the brickwork.

noise Any sound which is unwanted because it
is annoying, interferes with speech and hearing,
or is intense enough to damage hearing.

noise absorption See sound absorption.

noise control The technology of obtaining an
acceptable noise environment, consistent with
economic and operational considerations.

noise criterion curves See NC curves.

noise insulation See sound insulation.

noise isolation class (NIC) A single-num-
ber rating derived from measured values of noise
reduction between two enclosed spaces that are
connected by one or more paths.

noise level The sound level of a source of
noise; expressed in decibels, abbr. dB; measured
with a sound-level meter.

noise reduction, NR The difference in deci-
bels between the average sound pressure levels
produced in two rooms by a sound source in one
of them.

noise reduction coefficient, NRC The
average of the sound absorption coefficients of
an acoustical material at frequencies of 250, 500,
1,000, and 2,000 Hz, expressed to the nearest
integral multiple of 0.05.

NOM On drawings, abbr. for "nominal."

nominal diameter A designation used to
specify the size of a pipe, bolt, rivet, reinforcing

663

nominal dimension

steel bar, or rod, not necessarily equal to the
exact diameter.

nominal dimension l.In masonry, a dimen-
sion greater (by the thickness of a mortar joint)
than the dimensions of the actual masonry unit;
in the United States, not exceeding Vi inch (13
mm). 2. In lumber, a dimension that may vary
from the actual dimensions as provided for in
the local building code.

nominal mix The proportions of the con-
stituents of a proposed concrete mixture.

nominal size The dimensions of sawn lumber
before it is dried or surfaced. Also see dressed
size.

nominal strength The strength of a structural
member calculated in accordance with provi-
sions and assumptions of the strength design
method of the applicable code, before the appli-
cation of any strength-reduction factors.

nonagitating unit A container for carrying
concrete from a central location, where it is
mixed, to the job site; the unit does not agitate
the concrete enroute to the work.

non-air-entrained concrete Concrete in
which neither an air-entraining admixture nor
an air-entraining cement has been used.

nonautomatic sprinkler system A sprin-
kler system in which all pipes and sprinkler
heads are maintained dry and which is supplied
with water through a fire department Siamese
connection.

nonautomatic standpipe system A stand-
pipe system in which all piping is maintained
dry and which is supplied with water through a
fire department Siamese connection.

nonbearing partition See non-load-bearing
partition.

nonbearing wall A wall supporting no load
other than its own weight; a non-load-bearing
wall.

noncohesive soil A soil such as gravel or sand
in which the particles do not stick together, as
opposed to a sticky clay or claylike silt.

noncollusion affidavit A notarized state-
ment by a bidder that he has prepared his bid
without collusion of any kind.

noncombustibility That property of a mate-
rial which enables it to withstand high tempera-
ture without ignition.

noncombustible 1 . In building construction a
material of which no part will ignite and burn
when subjected to fire. 2. A building material
having a structural base of noncombustible
material, as defined above, with surfacing not
over Vb in. (0.32 cm) which has a flame-spread
rating not higher than 50. 3. A material, other
than those falling into the above two categories,
which has a flame-spread rating not higher than
25 and which shows no evidence of continued
progressive combustion.

noncombustible construction Construc-
tion in which the walls, partitions, and struc-
tural members are of noncombustible materials
and assemblies, but which does not qualify as
fire-resistive construction.

noncombustible material A material that
will not ignite, burn, support combustion, or
release flammable vapors when subject to fire or
heat, in the form in which it is used and under
conditions anticipated; any material that passes
ASTM Test Method E136 is considered non-
combustible.

nonconcordant tendons Tendons, in a sta-
tistically indeterminate structure, which are not
coincident with the pressure line caused by the
tendons.

nonconcurrent forces Forces that do not
have a common point of intersection.

nonconcurrent loads Two or more elements
of live or dead loads that, for design purposes, are
considered not to act simultaneously.

nonconforming Said of any building or struc-
ture which does not comply with the requirements
set forth in applicable code, rules, or regulations.

nonconforming work Work that does not
fulfill the requirements of the contract docu-
ments.

noncoplanar forces Forces that do not lie in
a single plane.

nondestructive test A test of a material,
component, or assembly which does not damage
the item being tested; usually carried out with
ultrasonics or x-rays.

non-displacement pile A pile which is
formed by boring or other excavation method.

nondrying Said of an oil, compound, etc.,
which does not oxidize in air and therefore does
not form a surface skin after application.

664

non-pressure pipe

nondrying oil An oil which does not oxidize
readily; esp. useful as a plasticizer.

nonelectric-delay blasting cap A blasting
cap with an integral delay element in conjunc-
tion with and capable of being detonated by a
detonation impulse or signal from a miniaturized
detonating cord.

nonevaporable water The water that is
chemically combined during cement hydration;
not removable by specified drying.

nonferrous Containing no, or very little, iron.

nonflammable Not combustible; also see flam-
mable.

nonfreeze sprinkler system A fire-protec-
tion sprinkler system designed for installation in
areas subject to freezing temperatures; usually a
dry-pipe sprinkler system.

non-grain-raising stain See NGR stain.

nonhabitable space By code: a space used for
a bath, boiler room, closet, dressing room,
heater, kitchenette, laundry, locker, pantry, stor-
age, toilet, utility; or for service and mainte-
nance of a building; or used for access and
vertical travel between stories; compare with
habitable space.

nonhydraulic lime A calcium- or dolomite-
type lime; used as a finish or mason's lime.

non-load-bearing partition An interior par-
tition which divides spaces within a building but
does not support floor joists or carry overhead
partitions.

non-load-bearing tile Ceramic tile designed
for use in masonry walls carrying no superim-
posed loads.

non-load-bearing wall A wall capable only
of supporting its own weight and (if it is an exte-
rior wall) capable of resisting the force of the
wind blowing against it; it cannot support an
imposed load. Compare with load-bearing wall;
also called a nonbearing wall.

non-lustrous glaze Said of an inseparable
ceramic glaze that has fire-bonded and non-
lustrous finish.

nonmetallic sheathed cable Two or more
insulated electric conductors having an outer
sheath of nonmetallic, flame-retardant, mois-
ture-resistant material.

nonmetallic tubing See electrical nonmetal-
lic tubing.

Surface Print

TYPE SE STYLE *

Copper
Conductors

RomaXtP

Insulation
Color Coded

PVC Jacket

Cable Tape

Bare Copper
Groundirtg Conductor

Annealed Uncoated Copper Conductws

Surface Print

_L_

TYPE NM-B (UL) 600 V

75°C PVC Jacket

Color Coded 90"C PVC Insulation

Surface Print

PVC Jacket

Concentric Conductor

Rome-XLP Insulation,
Color Coded

types of nonmetallic sheathed cable

nominal load The magnitude of the load spec-
ified by the applicable code.

non-performance Said of a building contrac-
tor's failure to perform the work, 1 called for in
the contract documents.

nonplanar frame A structural frame which is
composed of individual members in which at
least one of the members is noncoplanar with
the others.

non-pressure pipe Pipe designed for use in
conveying a liquid only by gravity; does not have
a pressure rating.

665

nonprestressed reinforcement

nonprestressed reinforcement In pre-
stressed concrete construction, reinforcing steel
which is not subjected to prestressing or postten-
sioning.

nonpublic fixture A plumbing fixture in-
tended for the use of a family or an individual
(for example, a W.C. in a residence or apartment
or a private toilet in a hotel or motel room).

nonrenewable fuse A fuse in an electric cir-
cuit which must be replaced after it has inter-
rupted the circuit by melting.

non-restrictive specification A building
specification that does not restrict the purchase
of a product to a specific manufacturer or to the
purchase of a material from a specific supplier.

nonreturn valve A combination check valve
and globe valve used at the discharge of a high-
pressure boiler.

non-sag sealant A compound that exhibits
little or no flow when applied in vertical or
inverted joints.

nonsimultaneous prestressing In prestressed
concrete construction, the posttensioning of ten-
dons individually, rather than simultaneously.

nonsiphon trap In plumbing, a trap, 1 whose
seal (usually between 3 and 4 in.; approx. 7.5
and 10 cm) is not easily broken; the diameter is
not greater than 4 in. (10 cm), and the water
held in the trap is not less than 1 qt (0.95 liter).

nonslip concrete Concrete having a rough-
ened surface, e.g., as a result of the sprinkling of
grains of an oxide to the surface before it hard-
ens or as the result of the roughening of the sur-
face with a coarse-bristled stiff brush before the
concrete sets; especially used for steps.

nonslip nosing On a stair, a nosing strip hav-
ing a rough surface.

nonstaining cement Masonry cement con-
taining not more than a specified amount of
water-soluble alkali as measured by a specified
test method.

nonstaining mortar A mortar having a low
free-alkali content to avoid efflorescence or
staining of adjacent stone by the migration of
soluble materials.

nonstop switch A manual switch in an eleva-
tor car, which prevents the elevator from mak-
ing registered landing stops.

non-vision glass Same as obscure glass.

nonvitreous tile Ceramic tile having a degree
of vitrification evidenced by a water absorption
greater than 3%; an exception is nonvitreous
floor and wall tile, which has a water absorption
above 7% but less than 18%.

nonvolatile In a paint film, that portion which
remains after the water, solvents, and diluents
have evaporated.

nook An alcove opening off a room to provide
additional or more intimate space, sometimes at
a fireplace or adjoining a kitchen for dining.

nook-rib A rib in one corner of a vault.

nook shaft A column or colonnette set in a
square break, as at the angle of a building, or
where the jamb of a doorway meets the external
face of a wall.

nook window A window in an inglenook.

NOP Abbr. for "not otherwise provided for."

noraghe Same as nuraghe.

Norfolk latch A type of thumb latch for a door
that has a long metal plate behind the latch to
protect the door finish; compare with Suffolk
latch.

normal aggregate A concrete aggregate of
more or less usual weight, in contrast to aggre-
gate using lightweight concrete.

normal cement Same as ordinary portland
cement.

normal consistency 1 . The degree of wetness
exhibited by a freshly mixed concrete, mortar, or
neat cement grout whose workability is consid-
ered acceptable for the purpose at hand. 2. The
physical condition of neat cement paste 30 sec
after completion of mixing, as determined with
the Vicat apparatus in accordance with a speci-
fied method.

normal consolidation The condition that
exists if a soil deposit never has been subjected
to an effective pressure greater than the existing
pressure, and if the deposit is completely consol-
idated under the existing overburden.

normal haul A haul whose cost has been
included in the cost of the excavation; no addi-
tional charges are due for haulage.

normal stress The component of stress which
is perpendicular to the plane on which the force
is applied.

666

north porch

normal-weight aggregate An aggregate hav-
ing characteristics between those of a lightweight
aggregate and a heavyweight aggregate.

normal-weight concrete Concrete having a
unit weight of approximately 150 lb per cu ft
(2,400 kg per cu m), made with aggregates of
normal weight.

Norman architecture The Romanesque archi-
tecture of England from the Norman Conquest
(1066) until the rise of the Gothic around 1 180.

Norman architecture

Norman brick A brick whose nominal dimen-
sions are 2% in. by 4 in. by 12 in. (8.5 cm by 10.2
cm by 30.5 cm).

Normandy cottage See French Eclectic archi-
tecture and Neo-French architecture.

Normandy joint In plumbing, a joint between
two unthreaded pipes which are connected by a
sleeve; the ends of the sleeve are made tight by
packing rings which are compressed between
bolting rings and the sleeve.

Norman French style Same as French Nor-
man style.

Norman slab A piece of glass cut from col-
ored, blown-glass bottles; used in some stained-
glass windows.

Norman style Same as Romanesque style.

north aisle The aisle of a church on the left
side of a church as one faces the altar; so called
because medieval churches almost invariably
had their sanctuaries at the east end and the
main doors at the west end.

SOUTH PORCH

north aisle

north-light roof In the northern hemisphere,
a sawtooth roof in which the glazing faces north.

north porch A porch which shelters the
entrance to a church; located on the left side of
the church as one faces the altar.

VESTRY AND
NORTH PORCH p ULP[T TOWER

FONT

DESK 1

north porch

667

north side

north side The left side of an altar of a church,

as one faces the altar.
Norway spruce See spruce.
nose See nosing.
nose key Same as foxtail wedge.
nosing, nose The prominent, usually rounded,

horizontal edge which extends beyond an

upright face below; as the projection of a tread

beyond a riser.

NOSING

nosing

nosing line, nose line The slope of a stair

determined by a line connecting the lead edge or

nosing of the stair treads.
nosing strip In stair construction, a molding

which has the same profile as the nosing on the

stair treads.

nosing strip

no-slump concrete Freshly-mixed concrete
with a slump of less than l A inch (6 mm).

notch A cutout in a log or timber, usually at or
near one of its ends, that is used to form a rigid
joint when mated with another appropriately
cutout log or timber at right angles to it; for
example, at the corners of a log cabin or log
house. See corner notch, diamond notch, dou-
ble-saddle notch, dovetail notch, half-cut notch,

half-dovetail notch, halved-and-lapped notch,
lap notch, log notch, round notch, saddle notch,
single notch, single-saddle notch, square notch,
V-notch.

notchboard A stringer in a flight of stairs.
notched bar test A type of impact test in

which the specimen is in the form of a notched
metal bar. Also see Izod impact test.

notched lap See notching.

notched molding, notch ornament An

ornament produced by notching the edges of a

band or fillet.
notched rafter A rafter having a notch on the

underside near its lower end; this enables it to be

fitted over, and fastened to, a horizontal timber

supporting the rafter.
notching Joining of timbers, usually meeting or

crossing at right angles, by cutting a notch in

one or both pieces.

notching

notching and cogging Same as cogging joint.

notch joist A joist having one end notched to
fit over a wood girder which supports it; the
lower edge of the joist is supported by a ledger, 2.

notch ornament See notched molding,
notice to bidders A notice contained in the
bidding requirements informing prospective

668

nut

bidders of the opportunity to submit bids on a
project and setting forth the procedures for
doing so.

notice to proceed Written communication
issued by the owner to the contractor authoriz-
ing him to proceed with the work, 1 and estab-
lishing the date of commencement of the work.

novelty flooring Flooring which is laid in an
unusual pattern.

novelty siding See drop siding.

nozzle l.The projecting part of a faucet, or the
end of a pipe or hose. 2. A welding nozzle. 3. In a
fire sprinkler system, a sprinkler which provides a
special water discharge pattern, directional spray
pattern, or other unusual characteristic.

NPL On drawings, abbr. for nipple.

NPS On drawings, abbr. for "nominal pipe size."

NR See noise reduction.

NRC Abbr. for noise reduction coefficient.

nt Abbr. for nit.

N-truss A Pratt truss.

NTS Abbr. for "not to scale."

nt wt Abbr. for "net weight."

nucleus In ancient construction, the internal
part of the flooring, consisting of a strong
cement, over which the pavement was laid,
bound with mortar.

nugget In seam welding, spot welding, or pro-
jection welding, the weld metal which joins the
parts.

nugget size The width or diameter of a nugget,
measured in the plane of the interface between
the pieces which are joined.

nuisance 1 . A public nuisance is said to exist in
a building, structure, or premise: (a) if it is insuf-
ficiently cleaned, drained, lighted, or ventilated
for the intended usage, (b) if it poses conditions
detrimental to public health or dangerous to
human life, and/or (c) if its air or water supplies
are unwholesome. 2. A continuing legal wrong,
usually committed by an owner or occupant of
property on neighboring persons or property.

nulling A quadrant-shaped detail on decorative
moldings, esp. in Jacobean architecture.

nunnery A convent for females.

nuns' choir A seating area in a church which
is reserved for nuns attending mass.

nuraghe, noraghe Prehistoric round towers and
agglomerations of stone huts peculiar to Sardinia.

nuraghe

nursery 1. A room or place set apart for small
children. 2. A place where plants, shrubs, and
small trees are grown, usually for transplanting
elsewhere.

nursery school A school for children of about
3 to 5 years of age.

nurse's call system In a hospital, an electri-
cally operated system by which patients or per-
sonnel can summon a nurse from a bedside
station or from a duty station.

nursing home A building or part thereof
used for the lodging, boarding, and nursing
care, on a 24-hr basis, of four or more persons
who, because of mental or physical incapacity,
may be unable to provide for their own needs
and safety without the assistance of another
person; provides facilities and services primar-
ily for in-patients who require nursing care and
related medical services less intense than those
given in a general hospital or an extended-care
facility.

nut A short metal block having a central hole
which is threaded to receive a bolt, screw, or
other threaded part. (See illustraion p. 670.)

669

nutmeg ornament

SQUARE HEXAGONAL JAM CASTELLATED

OS? Q

WING CAP THUMB STOP

common types of nuts

nutmeg ornament A common ornamental
feature of Early English work in the north of
England, resembling a half a nutmeg.

nylon A generic name for a family of polyamide
resins of extreme toughness; used to make fibers
and fabrics.

nymphaeum A room decorated with plants,
sculpture, and fountains (often decorated with
nymphs), and intended for relaxation.

670

OA On drawings, abbr. for "overall."

O/A Abbr. for "on approval."

O and M manual Short for "operations and
maintenance" manual for a building. Also see
owner's manual.

OAI Abbr. for outside air intake.

oak A tough, hard, high-density wood of the
temperate climates; rather coarse-textured,
ranging in color from light tan to pink or
brown; used for both structural and decorative
applications, such as framing timbers, flooring,
and plywood.

oakum A caulking material made from old
hemp rope fibers that have been treated with tar.

oak varnish A long-oil varnish for indoor use;
contains pigment which gives it a light yellow-
tan color.

OB On drawings, abbr. for "obscure."

obelisk l.A monumental, four-sided stone
shaft, usually monolithic and tapering to a pyra-
midal tip. 2. In Egyptian art, such a shaft mostly

covered with hieroglyphs; originally erected as a

cult symbol to the sun god.
oblique arch Same as skew arch.
oblique butt joint, oblique joint A butt

joint which does not form a 90° angle to the axis

of the piece.

obelisk

oblique butt joint

oblique grain Same as diagonal grain.
oblique section In a mechanical drawing, a

section taken through an object at an angle

(other than 90°) to its longest axis.
oblique vault A vault that is supported by two

walls which are parallel but not directly opposite

each other. Also called a skew vault.
OBS l.On drawings, abbr. for "obsolete." 2.

Abbr. for "open back strike."

obscure glass, visionproof glass Translucent
sheet glass, usually having one face roughened.

obscuring window A window glazed with
frosted or stippled glass or the like; used to pro-
vide privacy.

observation of the work A function of the
architect in the construction phase, during his
periodic visits to the site, to familiarize himself gen-
erally with the progress and quality of the work, 1
and to determine in general if the work is proceed-
ing in accordance with the contract documents.

observatory l.A structure, generally with a
rotatable dome, in which astronomical observa-
tions are carried out. 2. A place, such as an upper
room, which affords a wide view; a lookout.

671

obsidian

obsidian A natural volcanic glass, usually
black, with a bright luster; has relatively low
water content.

obtuse angle arch A type of pointed arch,

formed by arcs of circles which intersect at the
apex; the centers of the circles are nearer
together than the width of the arch.

obtuse angle arch

O.C.

OC, OC Abbr. for on center.

The use, or intended use, of

occupancy

building.
occupancy permit Same as certificate of
occupancy.

occupancy rate The total number of persons
per room, housing unit, etc.

occupancy sensor An electrical switching
device that turns on the lights in a room when
an occupant enters and turns them off when the
occupant leaves.

occupant load The total number of persons
that may occupy a building (or portion thereof),
an elevator, etc., at any one time.

Occupational Safety and Health Adminis-
tration (OSHA) An organization within the
US Department of Labor, whose responsibilities
include safety in the workplace; publishes stan-
dards in the US Code of Federal Regulations that
govern safety in buildings during construction
and during occupancy. These regulations may be
obtained directly from OSHA: Occupational
Safety and Health Administration, US Depart-
ment of Labor, 200 Constitution Avenue, NW,
Washington, DC 20210.

occupiable room A space for short-term
human occupancy as distinct from a space for
human habitation.

occurrence In insurance terminology, an acci-
dent or a continuous exposure to conditions which

result in injury or damage, provided the injury or
damage is neither expected nor intended.

ocher, ochre A naturally occurring yellow-
brown hydrated iron oxide; used as a pigment in
paint and a filler in linoleum.

OCT On drawings, abbr. for "octagon."

octagon barn A barn having an eight-sided plan;
relatively few of such structures were built prior to
1880, stimulated by interest in octagon houses.

octagon house An eight-sided house, usually
two to four stories high, built primarily in the
last half of the 19th century, although the octa-
gon plan was employed in some classical build-
ings. Often characterized by: a large porch;
exterior walls usually of wood or concrete; a low-
pitched roof, often topped with an eight-sided
cupola; occasionally a raised basement.

^■;, .

octastyle A temple facade or portico having
eight columns in the front or end row.

^ ^ td

3 V r

H W "P 1

octastyle

octave The interval between two frequencies
having the ratio of 2:1.

octave band The frequency range between
two frequencies whose ratio is exactly 2:1.

octave-band analyzer An electronic instru-
ment for measuring octave-band sound-pressure
level; consists of a microphone, amplifier, electric
filters, an indicator, and appropriate controls.

672

offset

octave-band sound-pressure level The
sound-pressure level of the sound within a spec-
ified octave band.

octopartite vault One of the vaults covering a
square space, enclosed by walls, with eight
oblique cells.

oculus l.See roundel. 2. See bull's-eye, 2. 3.

An opening at the crown of a dome.
OD On drawings, abbr. for "outside diameter."
odeion Same as odeum.
odeum, odeon A small ancient Greek or Roman

theater, usually roofed, for musical performances.

ode

Athe

odorless mineral spirit A thinner composed
of branch-chained aliphatic hydrocarbons; used
in paints because of its exceptionally low odor
level.

odorless paint A paint such as a water-base latex
paint or an oil- or alkyd-base paint which contains
an odorless mineral spirit as a thinner; produces a
minimum amount of odor during application.

odor test Same as scent test.

oecus In a house in the ancient Roman empire,
an apartment, hall, or large room.

oeil-de-boeuf, oxeye See bull's-eye, 2.

OFF. On drawings, abbr. for "office."

off-center 1 . Having an axis not along the geo-
metric center line. 2. Not at the center point.

off-count mesh In a wire cloth, a count which
is not the same in both directions.

offertory window See lowside window.

office building A building used for professional
or clerical purposes, no part of which is used for
living purposes, except by the janitor's family.

office divider Same as partial-height partition.

office landscape screen A fixed or movable,
free-standing, rearrangeable interior space divider;
may incorporate sound-absorptive properties.

office occupancy The use of a building for the
transaction of business or for similar purposes.

official map One legally established by a
municipality, which depicts existing parks,
streets, and drainage systems; land reservations
and rights-of-way for the future expansion of
these systems usually are depicted.

offlet Same as grip.

offsaw Descriptive of the actual size of a timber
after it has been sawn.

offset 1. A horizontal ledge on a wall (or other
member or construction), marking a decrease in
its thickness above; also called a watertable. 2.
A bend in a pipe. 3. A change in the direction of
a pipeline (other than 90°), e.g., by a combina-
tion of elbows or bends, which brings one sec-
tion of the pipe out of line with but into a line
parallel to another section. 4. A short line per-
pendicular to a surveyed line, measured to a line

offset, 2

673

offset bend

or point for which data are desired, thus locating
the second line or point with reference to the
first or surveyed line.

offset bend In a reinforcing bar, any bend that
displaces the center line of a section of the bar
to a position parallel to the original bar (the dis-
placement usually is relatively small); com-
monly used in reinforced concrete columns.

offset block A concrete masonry unit which is
not rectangular; usually used as a corner block to
maintain the masonry pattern on the exposed
face of a single-withe wall whose thickness is less
than half the length of the unit.

offset chimney Same as stepped-back chimney.

offset digging Digging with a ladder ditcher
whose boom is displaced from the line of travel
of the ditcher.

offset elbow A pipe fitting whose shape has
the outline of the letter S, used for connecting
lengths of straight pipe that are parallel to, but
displaced from, each other.

offset line A secondary survey line roughly par-
allel and close to a primary survey line to which
it is referenced in measured offsets.

offset pipe See offset, 3 .

offset pivot A pin-and-socket hardware
device with a single bearing contact, by means
of which a door is suspended in its frame,
allowing it to swing about an axis which nor-
mally is located about % in. (1.9 cm) out from
the door face.

offset screwdriver A screwdriver whose head
is set 90° to the shaft.

offset screwdriver

off-white White containing a slight amount of

gray, yellow, or other light color.
O.g., O.G. Abbr. for "ogee."
OG 1. Abbr. for "ogee." 2. Abbr. for "on grade."
ogee, OG l.A double curve, formed by the

union of a convex and concave line, resembling

an S-shape. 2. A molding having such a shape,

an ogee molding,
ogee arch A pointed arch composed of reversed

curves, the lower concave and the upper convex.

Compare with nodding ogee arch.

ogee, 2 left, Early English period; center, Decorated period;
right, Perpendicular period

ogee arch

ogee molding See ogee, 2.

ogee plane A carpenter's plane with a reverse
curved blade for shaping ogee moldings.

ogee roof A roof whose section is an ogee, 1 .

ogee roof

ogival arch Same as ogee arch.

ogive l.In general, a pointed arch. 2. Strictly,
the diagonal rib in Gothic vaults.

O/H Abbr. for "overhead."

ohm The unit of electrical resistance of a con-
ductor such that a constant current of 1 ampere
in it produces a decrease in voltage across it of
1 volt.

Ohm's law A law stating that the current in an
electric circuit is directly proportional to the
electromotive force (voltage) in the circuit and
inversely proportional to the resistance in the
circuit.

674

olive butt

OHS On drawings, abbr. for "oval-headed screw."

oil A lightly viscous neutral liquid belonging to
one of three classes: (a) animal oil, (b) mineral
oil, or (c) vegetable oil.

oil-base paint See oil paint.

oil-bound distemper A distemper which
contains a drying oil.

oil buffer A buffer consisting of a cylinder and
a piston or plunger where the oil in the cylinder
acts as a medium to absorb and dissipate the
kinetic energy of an impact, such as that of a
descending elevator car or counterweight acting
on the piston or plunger.

oil burner In a furnace or boiler, a burner in
which fuel oil is vaporized or atomized and then
mixed with air and ignited; the resulting flame is
directed upon the surface to be heated.

oil bu

oil-canning, tin-canning A slight buckling
in sheet metal, causing a wavy or uneven appear-
ance.

oil color An oil-base paint containing a high
concentration of colored pigment; commonly
used for tinting paint.

oilet See oillet.

oil-filled transformer A liquid-immersed
transformer in which the liquid is a hydrocarbon
or mineral oil.

oil furnace A furnace that is fired by oil.

oil-immersed fuse A fuse that is either totally
or partially immersed in an insulating dielectric
liquid of a transformer or switchgear.

oil-immersed switch A switch which is
immersed in a special insulating fluid, usually oil.

oil-immersed transformer See oil-filled trans-
former,
oil interceptor Same as interceptor.

oil length In a varnish, the number of gallons of

oil per 100 lb of gum or resin.
oillet, oillette A small opening, or circular

loophole, in a fortification of the Middle Ages.

oil of turpentine See turpentine.

oil paint A paint in which a drying oil is the

vehicle for the pigment.
oil preservative An oil-soluble chemical used

to treat wood for protection against decay and

insects. Also see creosote, pentachlorophenol.
oil separator In a refrigeration system, a device

for separating oil and oil vapor from the refriger-
ant, usually installed in the compressor discharge

line.
oil stain A stain containing dye or pigment

mixed with oil or oil varnish which penetrates

the surface to be finished.
oilstone A fine-grained stone used to impart a

sharp edge on tools; oil is used to lubricate the

rubbing surface.
oilstone slip See gouge slip.
oil switch Same as oil-immersed switch.
oil varnish A high-gloss varnish for interior

use; made by heating or blending a drying oil

with a gum or resin.
oil white A house-paint pigment consisting of

lithopone and white lead or zinc white.
okoume See gaboon.
okwen See zebrawood.
old English bond Same as English bond.

Old English style Same as Domestic Revival
style.

old 'wood Wood which has been worked previ-
ously and is reused.

olefin A lightweight, high-strength, long-
chain polymeric material having very good
abrasion resistance; especially used in indoor-
outdoor carpeting.

oleoresin A natural resin containing essential
oils; used in adhesives, varnishes, and various
compounds.

oleoresinous varnish A varnish consisting of
a drying oil compounded with a hardening resin.

olive butt Same as olive knuckle hinge.

675

olive hinge

olive hinge Same as olive knuckle hinge.

olive knuckle hinge A paumelle hinge with
knuckles forming an oval shape.

olive knuckle hinge

Olmec architecture Architecture of the most
ancient civilization of Mesoamerica (1500-400
B.C.) usually characterized by: a north-south ori-
entation of the ceremonial center, stepped pyra-
mids, sloping walls, ceremonial courtyards, and
platforms on which to construct temples.

omnidirectional microphone A micro-
phone which is equally sensitive in all directions.

on»center Same as center- to-center.

on-condition maintenance Maintenance of
machinery when condition monitoring equip-
ment indicates that a mechanical failure is about
to occur.

one-and-a-half-story See story-and-a-half.

one-and-one-half-bay cottage Same as three-
quarter Cape Cod house.

one-and-one-half-story house A one-story
house having a loft space between the ceiling of
the first floor and the roof directly above; win-
dows in the gable-end walls and/or dormers pro-
vide light and ventilation in this loft space,
providing the additional half-story.

one-bay cottage Same as half Cape house, 1.

one-brick wall See whole-brick wall.

one-centered arch Any arch struck from a
single center, such as a round, segmental, or
horseshoe arch.

one-line diagram A representation of an elec-
trical system by means of single lines and graphic
symbols showing the major components of the
system.

one-over-one 1 . A two-story cottage having
two rooms, one directly over the other; usually
the result of the expansion of a cottage having a
one-room plan by the addition of a floor above
it. 2. A term descriptive of a double-hung win-
dow having one pane in the upper sash and one
pane in the lower; see pane.

one-part adhesive An adhesive that sets
without the addition of a catalyst or hardener.

one-pipe heating A heating system in which
a centrally-located heater distributes hot water
serially to individual heaters in a home or office
building.

one-pipe system A plumbing system in which
a single pipe carries both soil and waste.

one-pour system A batch of concrete that is
completely poured at a single time. Compare
with two-pour system.

one-room cottage A cottage having a one-
room plan, usually with a loft space above.

one-room cottage

one-room plan The earliest and simplest floor
plan for a dwelling, especially used in 17th cen-
tury and beyond; consisted of a single room, usu-
ally called a hall or keeping room, that served as a
combination living room, dining room, kitchen,
and workroom; cooking was done in a large fire-
place set into a massive chimney. In some regions,
the front door of the house opened into a small
vestibule called a porch, but in other regions, the
door opened directly into the hall; access to a loft
above was provided either by a staircase in the
vestibule or by a ladder in the hall. Many such
houses were enlarged by the addition of a second
room at ground level, called the parlor, giving rise
to the hall-and-parlor plan; the parlor served as a
combination living room and sleeping room for
the parents. Also see one-over-one, 1.

676

opaion

one-room schoolhouse A school in which
all elementary-grade students were once
taught in a single room. Such schools were
common in sparsely populated areas before the
20th century; many had a bell at the ridge of
the roof for summoning students at the start of
the school day.

one-sided connection A connection of one
structural member to a second which is not sym-
metrical about the component part of the mem-
ber being connected.

one-time fuse Same as nonrenewable fuse.

one-way joist construction A type of fram-
ing system for floors or roofs in a concrete build-
ing; consists of a series of parallel joists which are
supported by girders (perpendicular to the joists)
between columns.

one-way slab A rectangular reinforced con-
crete slab which spans a distance very much
greater in one direction than the other; under
these conditions, most of the load is carried on
the shorter span.

one-way system In reinforced concrete, a sys-
tem of steel reinforcement within a slab that is
assumed to bend in one direction only.

one-way throw A supply grille that deflects
the outgoing air in one direction only.

on»glaze Decorations executed with enamel
on ceramic glaze and then fired in a kiln in

which heat alone, not flames, is permitted to
enter.

on-grade 1. Directly on the ground. 2. At

ground level.

onion dome In Russian Orthodox church
architecture, a bulbous dome which terminates
in a point and serves as a roof structure over a
cupola or tower.

onion-domed tower An onion dome placed
on a tower whose height is large compared to its
diameter; once a characteristic of Baroque
church architecture in southern Germany,
where one onion dome was sometimes placed
atop another.

on-off sprinkler In a fire protection system, a
sprinkler similar in performance characteristics
to a conventional sprinkler but having the addi-
tional feature of closing when the temperature
drops to a preselected value.

church surmounted by an onion dome

on-site-observation Same as observation of
the work.

onyx A banded, varicolored form of quartz,
closely related to agate; cut into slabs, polished,
and used for decorative building stone.

oolite A granular limestone, each grain of
which is more or less spherical and made up of
concentric coats of carbonate of lime formed
around a nucleus.

oolitic limestone A type of limestone charac-
terized by minute spherical calcareous particles.

opa In a classical temple, a cavity which re-
ceives a roof beam.

opacity The quality of being opaque, as the
capacity of a paint to cover or obliterate a back-
ground over which it is applied.

opaion l.In ancient Rome and Greece, an
opening (as in a roof) for smoke to escape. 2. In
Greek architecture, a lacunar.

677

opal

opal A hydrous form of silica containing 2 to
10% combined water; reacts with cement alka-
lies and may be highly detrimental as an aggre-
gate in concrete.

opalescent glass A multicolored iridescent
glass first used by the painters Louis Comfort
Tiffany (1848-1933) and John La Farge
(1835-1910) in the late 19th century; now often
referred to as Tiffany glass .

opalescent glaze A glaze having a milky
appearance.

opal glass A diffusing glass of milk-white
appearance formed by incorporating material of
high refractive index in the glass to scatter light.

opaline chert Chert that is principally or
entirely of opal.

opal lamp bulb A bulb in which part or all of
the glass envelope has a white, highly diffuse
finish.

opaque Impervious to the transmission of visi-
ble light.

opaque ceramic-glazed tile A facing tile
whose surface faces are covered by an insepara-
ble fire-bonded, opaque, colored ceramic glaze of
bright satin or glass finish.

open assembly time The time between the
application of glue to joints (or wood veneer)
and the assembly.

open bidding This type of bidding is fre-
quently used to conform to legal requirements
pertaining to public projects.

open boarding Roofing boards which are laid
with a gap between adjacent boards.

open building system A building system
which is designed so that its subsystems are
interchangeable with like subsystems, its sub-
assemblies are interchangeable with like sub-
assemblies, and its components or building
elements are interchangeable with like build-
ing components or elements of other systems.

open cell In foam rubber, cellular plastics, etc.,
a cell which interconnects with other cells.

open chapel A chapel, one side of which faces
the open air.

open-cell foam A cellular plastic in which
there is a predominance of interconnected cells.

open circuit A discontinuous electric circuit
through which no current can flow.

open-circuit grouting A system for pumping
grout in which there is no provision for recircu-
lating the grout to the pump.

open competitive selection The process of
selecting a contractor in which an advertise-
ment for bids is published in the news media to
notify qualified contractors of the owner's inten-
tion to receive sealed competitive bids.

open construction Said of a building compo-
nent, building assembly, or building which is
manufactured in such a way that all portions can
be readily inspected at the installation site with-
out disassembly or destruction.

open cornice, open eaves Overhanging eaves
where the rafters are exposed at the eaves and can
be seen from below.

open cornice

open crenelation A wood crenelated mold-
ing of perforated, open design; often used in
Gothic Revival buildings in Colonial America.

open cut An excavation, open to the sky,
which has been cut from the ground surface
downward, in contrast to tunnel excavation.

open defect An unfilled hole or gap in lumber,
plywood, or wood veneer.

open eaves See open cornice.

open-end block 1 . An A-block or an H-block
concrete masonry unit. 2. A standard block hav-
ing recessed end webs.

open-end mortgage A mortgage which per-
mits the mortgager to borrow additional funds
for improvements after the original loan has
been made and permits him to repay them over
an extended amortization period.

open exterior space Space without roof and/or
side closure, capable of serving for egress to a
street or other public space.

open floor A floor whose joists are visible from
the floor below.

678

open sheeting

open»floor system Same as open plan system.

open-frame girder Same as Vierendeel truss.

open-graded aggregate An aggregate con-
taining little or no mineral filler, or in which the
void spaces in the compacted aggregate are rela-
tively large.

open-grain, open-grained Having a coarse
texture. Also see coarse-textured, wide-ringed.

open heart molding A common Norman
molding consisting of a series of overlapping
shapes resembling the outlines of a heart.

open impeller In a pump, an impeller that
does not have shrouds (i.e., disks that enclose
the impeller vanes); usually used where the
water being pumped contains suspended solids.

open impeller

open industrial structure A structural plat-
form used for required access to industrial opera-
tions conducted in the open air, such as oil refining
and chemical processing; often, a roof or canopy is
provided for shelter, but there are no walls.

opening door See active leaf.

opening leaf See active leaf.

opening light In a window, the light (as a sash)
that opens and closes, in contrast to a fixed
light.

opening of bids Same as bid opening.

opening protective A device for protecting
an opening from the passage of flame, smoke, or
hot gases.

opening size See door opening.

open mortise See slot mortise.

open-newel stair A spiral stair constructed
around an open cylindrical space without a cen-
tral post, in contrast to a solid-newel stair built
around a post.

open parking structure A structure, nor-
mally open to the outdoors on two or more sides,
for the temporary storage of motor vehicles.

open pediment Same as broken pediment, 1.

open plan A building plan with a minimum of
internal subdivision between spaces designed for
different usage.

open-plan educational building An edu-
cational building, or portion thereof, having
corridors that do not comply with code require-
ments for exterior exit corridors.

open-plan office A large space, divided by free-
standing, partial-height partitions; usually designed
to accommodate a large number of office workers.

open plumbing Plumbing which is exposed;
the traps and drainage pipes, beneath the fixtures,
are accessible, ventilated, and open to inspection.

open riser The space between two adjacent
treads in a stair when such space is not filled by
a solid riser.

open-riser stair A stair not having risers.

open roof, open-timbered roof A roof con-
struction in which the rafters and roof sheathing
are visible from below; there is no ceiling.

open shaft A vertical duct or small enclosed
passage within a building, open to the outer air
at the top, and used to ventilate interior spaces
connected to it. Also see light well.

open sheathing See open sheeting.

open sheeting, open sheathing, open tim-
bering Horizontal or vertical planks or boards
placed at intervals along the face of an excava-
tion; used where the soil is sufficiently firm to
make close sheeting unnecessary and where
groundwater is not a problem.

WALE

-STRUT

open sheeting

679

open shelving

open shelving Shelving which is exposed, not
concealed by a door or cabinet.

open shop A construction project operating
under a work system that does not require mem-
bership in a particular union as a condition of
employment. Compare with closed shop.

open slating, spaced slating In roofing, a
slating pattern in which spaces are left between
adjacent slates in a course.

open slating

open solar energy system A solar energy
system whose storage tank is open to atmo-
spheric pressure.

open space In urban planning, the designation
given parks, recreational and natural areas, or
other land not occupied by buildings.

open»space index The reciprocal of coverage, 3 .

open sprinkler A fire sprinkler (i.e., sprinkler
head) with a normally open nozzle.

open stage In a theater, a stage platform not
bounded by a proscenium arch.

open stair, open-string stair A stair whose
treads are visible on one or both sides.

open stair, open-string stair

open stairway A stairway, one or both sides of
which are open to a room in which it is located.

open string An inclined board in a vertical
plane, parallel to the slope of a stair (i.e., a
string), whose upper edge is cut to fit the profile
of the treads and risers of the steps; the treads of
the stairs project beyond the face of the string
and are visible; compare with closed string.

open-string stair See open stair.

open system A fluid piping system in which
the circulating fluid is connected to an open-
vented elevated tank, to a cooling tower, or the
like; the tank serves as a reservoir to accommo-
date the expansion and contraction of the fluid,
and as a convenient location for inspecting the
condition of the fluid.

open tendering See open bidding.

open-timbered Having timberwork exposed;
having the wooden framework not concealed by
sheathing, plaster, or other covering.

open-timbered roof Same as open roof.

open-timber floor A floor in which the floor
joists and construction are exposed on the
underside.

open timbering See open sheeting.

open time The time interval between the
spreading of an adhesive and the completion of
the bond.

open-top agitating truck A special truck
which serves as an open-top mixer, maintaining
previously mixed concrete in a uniform condi-
tion by means of agitator rotor blades; has a
specially shaped watertight metal body with
smooth, streamlined surfaces and a discharge
gate at the rear.

open-top mixer A mixer filled through an
opening at its top; for concrete, usually a pan or
drum within which mixing blades revolve about
the vertical axis; for mortar, usually a trough
within which mixing paddles revolve about the
horizontal axis.

open traverse In surveying, a survey traverse
in which the final line does not join the starting
point.

open-web joist A truss whose web has a pattern
of crisscrossed steel members in contrast to the
solid piece shown in the illustration of web, 1.

open valley A type of valley on a roof. The
valley formed at the intersection of two roof
surfaces is lined with metal or mineral-surfaced
roofing, and the shingles or slates are not laid

680

optical fiber cable

to this intersection, leaving the metal lining
exposed.

open web A web, 1 composed of a group of
members (in a crisscross or zigzag array) instead
of solid plates.

open-web steel joist A steel truss having an
open web whose component parts are either
hot-rolled structural shapes or cold-formed
light-gauge steel shapes.

open 'well A floor opening, a series of such
openings, or an atrium of two or more stories
that does not meet code requirements (with
respect to enclosure) for a covered shaft.

open»well stair Same as open-newel stair.

open-wire circuit An electric circuit consist-
ing of conductors which are separately supported
on insulators.

open 'wiring Electric wiring which uses cleats,
flexible tubing, knobs, and tubes to protect and
support insulated conductors run on or in a
building; not concealed by the building structure.

openwork 1 . Any work, esp. ornamental, char-
acterized by perforations. 2. In fortifications, any
work not protected at a gorge, 3 by a parapet or
otherwise.

operable partition A partition composed of a
number of large panels which are hung from a
ceiling track, permitting the panels to be moved
easily from their closed position (in which the
panels form a partition) to an open position (in
which the panels are stacked against each
other); the panels also may be supported by a
floor track.

operable transom A panel or glass light,
above a door, which may be opened for venti-
lation.

operable wall Same as operable partition.

operable window A window which may be
opened for ventilation, as opposed to a fixed light.

opera house A theater intended primarily for
the public performance of operas.

operating pressure The pressure indicated by
a gauge in part of a system, when the system is in
normal operation.

opisthodomos, epinaos, opisthodomus,
posticum The inner portico at the rear of
the cella of a classical temple, corresponding to
the pronaos in front.

• • 6"& • •

t> a o $ G~9^d

opisthodomos

OPNG On drawings, abbr. for "opening."
OPP On drawings, abbr. for "opposite."
opposed-blade damper A damper, 1 through
which the airflow is adjusted by means of two
sections of damper blades on a common linkage,
arranged so that adjacent blades rotate in oppo-
site directions. (See illustration p . 682.)

optical detector See photoelectric smoke
detector.

optical fiber cable An optical signal trans-
mission medium consisting of (a) a glass fiber
or plastic fiber (or filament) surrounded by
protective cladding, (b) strengthening mate-
rial, and (c) an outer jacket. Signals may be
transmitted, along the cable, as light pulses

681

optical plummet

opposed-blade damper

PVC
PVC SHEATH COVER

COATED FIBER

PVC BUFFER

optical tiber cable

introduced into the fiber by a laser or light-
emitting diode. Its advantages over the trans-
mission of electrical signals along (metal) wire
cable include low attenuation along the cable,
freedom from electromagnetic interference
and electrical grounding problems, small phys-
ical size, light weight, and large transmission
bandwidth.

optical plummet A device on some transits
and theodolites; used to center the instrument
over a point, in place of a plumb bob, which
moves in a strong wind.

optical refinements In Greek architecture
and derivatives, a set of adjustments of normal
shaping and spacing made supposedly to coun-
teract the somatic peculiarities of human vision.
Also see entasis.

optical smoke detector See photoelectric
smoke detector.

optimum moisture content That content
of water in soil at which the maximum dry unit
weight can be attained as a result of a given com-
paction effort.

optimum reverberation time In a room or
auditorium designed for speech, the reverbera-
tion time that provides the highest speech intel-
ligibility consistent with other requirements. In
a room or auditorium designed for music, the
reverberation time that provides optimum con-
ditions for playing and listening to music. These
optimum values depend on the use of the room,
its volume, and may depend on frequency.

option An agreement between an owner and
prospective user of a property which, for a speci-
fied sum, grants the latter the right to buy or rent
the property within a specified period of time.

opus Alexandrinum A mosaic of relatively
large pieces of marble or stone, cut to shape and
arranged in geometric patterns, usually a mosaic
pavement consisting of geometrical figures in
black and red tesserae on white ground.

opus antiquum Same as opus incertum.

opus caementum Ancient Roman masonry
formed of small rough stones set in a mixture of
concrete composed of sand, lime, and often
pozzolan.

opus incertum In ancient Rome, masonry
formed of small rough stones set irregularly in mor-
tar, sometimes traversed by beds of bricks or tiles.

opus incertum

opus interrasile Decoration produced either
by cutting away the ground and leaving the pat-
tern or by cutting out the pattern so that the
openings form the design.

opus isodomum Same as isodomum.

opus latericium, opus lateritium Roman
masonry of brick or tiles, or of a brick or tile fac-
ing on a concrete core.

opus listatum A Roman wall constructed of
bricks and stone in alternate layers.

opus lithostrotum Same as lithostrotum opus.

opus musivum A Roman mosaic decoration
employing small cubes of colored glass or enam-
eled work.

682

orchestra

opus pseudoisodomum In ancient Roman
masonry, coursed ashlar having courses of
unequal height.

opus quadratum Masonry of squared stones
in regular ashlar courses.

opus quadratum

opus reticulatum A decorative Roman wall
facing, backed by a concrete core, formed of
small pyramidal stones with their points embed-
ded in the wall, their exposed square bases, set
diagonally, forming a net-like pattern.

opus reticulatum

opus sectile See sectile opus.

opus signinum An ancient Roman construc-
tion material which was employed as flooring;
consisted of tiles, broken into tiny pieces, that
were mixed with mortar.

opus spicatum Masonry of the ancient
Romans that is laid in a herringbone pattern.

opus tectorium A type of stucco used in
ancient Rome; used to cover walls in three or
four coats, the finishing coat being practically an
artificial marble, usually polished to serve as a
surface for paintings.

opus tesselatum A pavement with designs
executed in pieces of different-colored tesserae,
of larger size and more regular form than the
pieces used in mosaic.

opus testaceum An early Roman concrete
masonry faced with fired brick.

opus vermiculatum See vermiculated mosaic.

OR Abbr. for "outside radius."

orange peel, orange peeling l.In a paint
film, a surface defect characterized by a rough

texture resembling orange peel; results from the
poor flow of paint or a poor application technique.
2. In ceramics, an irregular waviness of porcelain
enamel surface; resembling an orange skin in tex-
ture; sometimes considered a surface defect.

orangery A building, or a part of a building,
once found in especially stately homes, for culti-
vating orange trees and other ornamental trees
in a cool climate where they would not other-
wise grow; usually had large, tall windows along
its southern exposure; now often used for social
and exhibition purposes. Also see conservatory,
greenhouse, hothouse.

orange shellac A refined lac (a secretion of
insects), which is soluble in alcohol; contains
some wax and resin; used as a coating on floors
and other wood surfaces.

oratory A small private chapel furnished with
an altar and a crucifix.

An ancient oratory in Ireland

orb l.A plain circular boss, as a decorative
accent where two or more ribs (of a vault) cross.
2. The medieval name for the tracery of blank
windows or stone panels.

orbital sander An electric-powered hand tool
used in rapid sanding, usually for coarse work;
the base of the machine, to which sanding paper
or abrasive cloth is clipped, moves in an ellipti-
cal pattern.

orchestra l.In the early Greek theater, the
place occupied by the dancers and chorus about
the altar of Dionysos; later, the circular space
reserved for the dancers and chorus, between the
proscenium and auditorium. 2. In the early
Roman theater, a semicircular level space be-
tween the stage and the first semicircular rows
of seats, reserved for senators and other distin-
guished spectators. 3. In an auditorium, the seat-
ing area on the main floor, or a forward section
of seats on the main floor.

683

orchestra circle

orchestra circle See parquet circle.

orchestra pit A pit immediately in front of, or
wholly or partly under, the forestage of an audi-
torium.

orchestra shell A massive, sound-reflective
structure which closes off the flies and wings of a
theatrical stage to form a performing area for
music, or is used in an open-air theater to direct
sound to the audience.

ord Abbr. for "order."

order l.In Classical architecture, an arrange-
ment of a particular style of column together
with the entablature (which it supports) and
standardized details, including its base and
capital. The Greeks developed the Corinthian
order, Doric order, and Ionic order; the
Romans added the Composite order and Tus-
can order. For each order, the height and spac-
ing of the columns is established in terms of a
specified number of diameters of the lower part
of the columns; the design of the base and cap-
ital is also prescribed. The height of the entab-
latures is determined by the height of the
columns. 2. In masonry, one ring of several
around an arch.

CORNICE

FRIEZE
ARCHITRAVE

CAPITAL

SHAFT

BASE

CAP
DIE
BASE

Doric order, 2

An arch of two orders, 3, each having its carved hood molding

ordinance A law or rule adopted by a local
governmental authority.

ordinary A village tavern in an early American
community.

ordinary construction Construction in which
the exterior bearing walls (or the bearing portions
of exterior walls) are of noncombustible materials
having a minimum fire endurance of 2 hr and sta-
bility under fire conditions; the nonbearing exte-
rior walls are of noncombustible construction;
the roof, floors, and interior framing are wholly
or partly of wood (or other combustible material)
of smaller dimensions than required for heavy-
timber construction.

ordinary-hazard contents Building con-
tents which are liable to burn with moderate
rapidity and give off a considerable volume of
smoke, but in so doing will not release poisonous
fumes or gases that could result in an explosion.

ordinary-hazard occupancy An occupancy
in which it is expected that there will be a rela-
tively moderate rate of heat release if a fire should
occur and (Group 1 ) the quantity of combustibles
is moderate, and the heights of the stockpiles of
combustibles do not exceed 8 feet (2.4 m), or
(Group 2) the quantity of combustibles is moder-
ate to high, and the heights of the stockpiles of
combustibles do not exceed 12 feet (3.7 m).

ordinary portland cement, Type I port-
land cement A portland cement used for

684

original construction

general construction which is produced without
any of the special distinguishing qualities
imparted to other types.

Oregon pine Common Douglas fir.

or equal See approved equal.

organic Said of a material or compound derived
from vegetable or animal life.

Organic architecture Architecture whose de-
sign is established in accordance with processes
of nature rather than based on an imposed
design; a design philosophy of Frank Lloyd
Wright (1867-1959) based largely on his early-
20th-century assertion that a building (and its
appearance) should follow forms that are in har-
mony with its natural environment. The materi-
als used on the exterior should be sympathetic to
the building's locale, thereby relating the build-
ing to its setting, as if it were the result of natural
growth. Thus, use should be made of low-
pitched overhanging roofs to provide protection
from the sun in the summer and to provide some
weather protection in the winter, and maximum
use should be made of natural daylighting.

organic clay A clay with a high organic content.

organic-coated glass Glass that is coated and
bonded on one or both sides with an applied
polymeric coating.

organic coating A coating (such as paint, lac-
quer, enamel, or film) in which the principal
ingredients are derived from animal or vegetable
matter or from some compound of carbon.

organic silt A silt with a high organic content.

organic soil Soil with a high organic content;
in general, organic soils are very compressible
and have poor load-sustaining properties.

organ loft In a church, the gallery or loft where
the organ is located, usually high above the floor.

organ screen 1 . An ornamental screen of
stone or timber which closes off the organ cham-
ber in a church. 2. A rood screen which supports
an organ.

oriel 1. In medieval English architecture, chiefly
residential, and derivatives: (a) a bay window
corbeled out from the wall of an upper story; (b)
a bay projecting, inside or out, extending a
room; (c) a windowed bay or porch at the top of
exterior stairs. 2. (rare) In medieval Continental
structures and derivatives, a subsidiary bay, or a
corbeled, enclosed feature, exterior or interior.

Oriental Revival A term descriptive of a
mode of Exotic Revival architecture that is sug-
gestive of the architecture of the Middle East
and/or Far East.

Oriental Revival

orientation 1 . The placement of a structure on
a site with regard to local conditions of sunlight,
wind, and drainage. 2. The siting of a Christian
church so that the main altar is housed toward
the east end of the building, a common ritual
disposition. 3. The relationship of a building site
plan to the points of a compass.
ORIG On drawings, abbr. for "original."
original construction That part of a building
that was constructed at a time when the building
was first erected, as opposed to additions, alter-
ations, and reconstructions at a later date.

685

original lean-to

original lean-to Same as integral lean-to.
orillon Same as crossette.

O'ring A resilient ring used as a gasket in seal-
ing a joint.

orle, orlet A narrow band, or series of small
members, taking the form of a border.

orlo l.A plinth which supports the base of a
column. 2. The smooth surface between parallel
flutes or grooves. 3. An orle.

ormolu 1 . Gold crushed with mercury to form a
paste. 2. An article or ornamental applique of
bronze, first coated with such paste, then heated to
evaporate the mercury, leaving pure gold evenly
and securely deposited. 3. Any metal or substitute
finished to resemble mercury-gilded bronze.

ormolu varnish A varnish having the appear-
ance of gold or gilded bronze.

ornament In architecture, every detail of
shape, texture, and color that is deliberately
exploited or added to attract an observer.

ornamental cast iron See cast-iron lacework.

ornamental facing A decorative effect obtained
by laying brick, stone, or tile in an attractive pre-
sentation on a wall.

ornamental ironwork Ironwork that is
merely decorative (such as cast-iron lacework), as
opposed to ironwork having a structural function.

ornamental plaster A plaster element, deco-
rative in nature, such as a ceiling medallion;
usually cast using plaster of paris.

ornate Highly ornamented.

orpiment An arsenic sulfur compound; used in
paints as a yellow pigment.

orthographic projection Projection in which
exact views of an object are constructed by
extending perpendiculars from points on the
object to the plane of projection.

orthography In drafting, a geometrical repre-
sentation of an elevation or section of a building.

orthostat One of many large stone slabs, set as a
revetment at the lower part of the cella in a clas-
sical temple, or at the base of a wall in the
ancient architecture of Anatolia, northern Syria,
and Assyria.

orthostate l.A stone taller than wide. 2. A
stone in the lower course of a wall, higher than the
regular blocks of the courses above, sometimes
serving as a high base for a wall of sun-dried brick.

orthostat

orthostyle Said of a colonnade in a straight line.

orthotropic Having dissimilar elastic proper-
ties in two mutually perpendicular directions;
i.e., orthogonal-anisotropic.

OSHA l.Abbr. for "Occupational Safety and
Health Administration," Department of Labor.
2.Abbr. for "Occupational Safety and Health
Act."

osier See withe, 2.

Osiride, Osirian column In ancient Egypt, a
type of column in which a standing figure of
Osiris is placed before a square pier; it differs
from the classical caryatid in that the pier, and
not the figure, supports the entablature.

ossature The framework or skeleton of a build-
ing or part of a building, as the ribs of a groined
vault or the frame of a roof.

ossuary, bone house, ossarium A storage
place for the bones of the dead; either a structure
or a vault lined with such bones ornamentally
arranged.

ostensory, monstrance A device in which
the Eucharistic wafer may be displayed.

ostiole A small entrance.

ostiolum A small opening; a small door.

Ottawa sand Naturally rounded grains of nearly
pure quartz, produced by processing silica sand
obtained from deposits near Ottawa, 111.; used in
mortar test specimens in testing hydraulic cement.
Also see standard sand, graded standard sand.

Ottoman architecture The later phase of
Turkish Muslim architecture, from the 14th cen-
tury onward, much influenced by Byzantine forms.

Ottonian architecture The pre-Romanesque
round-arched architecture of Germany during
the rule of the Ottonian emperors in the second
half of the 10th cent.

686

outlet ventilator

oubliette A secret dungeon in the deepest parts
of a medieval stronghold, having as its only entry
a trapdoor through which prisoners were dropped.

oundy molding See wave molding.

outage A failure in the electric power supplied
by a utility company.

out and out Same as overall.

outband In masonry, a jambstone which is laid
as a stretcher and cut to take a frame.

outbond Bonded, or forming a bond, along the face
of a wall; composed largely or entirely of stretchers.

outbuilding A building subsidiary to, but sepa-
rate from, a main house or building.

outcrop That portion of a rock formation or
stratum that breaks the surface of the ground.

outdoor-air intake Same as outside-air intake.

outdoor carpet Carpet, generally all-synthetic,
that has been especially engineered to resist the
effects of exposure to sun, rain, and/or snow.

outer bailey The courtyard outside the central
defenses of a medieval castle; often contained hous-
ing and service facilities for the local population.

outer hearth See front hearth.

outer lining Same as outside casing.

outer string The string at the outer and
exposed edge of a stair, away from the wall.

outfall The place of ultimate deposit of drainage
or sewage waters.

outfall sewer A sewer that receives the
sewage from a sewage collection system and
carries it to the point of final discharge or
treatment. It is usually the largest sewer in the
system.

outhouse l.A detached outdoor structure
housing a primitive toilet; usually constructed of
wood, rather than the proverbial brick. 2. A
small accessory building generally located at the
rear of a house and used for domestic animals,
storage, and so on.

outkitchen A kitchen once a subsidiary to,
and separate from, a large main house. This sep-
aration avoided overheating the house during
hot summer weather, minimized the possibility
of accidentally setting the house on fire, and
minimized cooking odors in the house.

outlet 1. In an electric wiring system, a point at
which current is taken to supply appliances,
portable equipment, etc. 2. In a gas pipe system, a
threaded connection or bolted flange to which a
gas-burning appliance may be attached; accord-
ing to code, the outlet must be located in the
room or space where the appliance is, or may be,
installed.

outlet box In an electric wiring system, a metal
box at an outlet which encloses one or more
receptacles.

outer bailey

outlet box

outer court A space partially bounded by build-
ing walls or property lines but open to the sky and,
on one side, to the street or other public space.

outlet ventilator A louvered opening in an
attic space to provide an outlet to the out-
doors. (See illustration p . 688.)

687

outline lighting

outlet ventilator

outline lighting An arrangement of incandes-
cent lamps or gaseous tubes which outlines and
emphasizes certain features such as the shape of
a building or the decoration of a window.

outline specification A preparatory specifi-
cation, not necessarily complete but containing
sufficient detail to serve as the basis for a con-
tract specification; usually included with design
development documents or schematic design
documents.

outlooker l.Same as outrigger. 2. A covering
over a doorway or opening in the face of a build-
ing to provide a small degree of shelter; also see
hanging gable.

out-of-center Same as off-center.

out-of-plumb Not truly vertical, according to
a plumb line.

out-of-sequence service A service per-
formed in other than the normal or natural order
of succession.

out»of»true Not in exact alignment (as a part
which is slightly twisted).

out of winding Said of a member that is free
from twist.

outrigger A beam at the ridge of a roof that
extends beyond the end wall of the building to
serve as a support for hoisting tackle or the like;
also called an outlooker or lookout.

outrigger scaffold A scaffold supported by
brackets fastened to the wall of a building.

outrigger shore, horsing A temporary bracket
to support a projecting feature.

outshot The extension of a building under a
lean-to roof.

outshut Same as outshot.

outside-air intake An opening or inlet
through which outside air is brought into an air-
conditioning system or into a boiler room. Also
called a fresh-air intake.

outside architrave See outside casing.

outrigger, 1

outside caliper A type of caliper which is
especially designed for measuring the outside
diameters of round or cylindrical objects.

outside casing, outside architrave, outside
facing, outside lining, outside trim In a
cased window frame, the members of the jamb or
head which face outside of the building and
appear as trim.

outside casing

outside chimney Same as exterior chimney.

outside corner molding A molding covering
the salient angle of two intersecting surfaces either
to protect the corner or to cover the exposed edge
of the surface material as in wood veneer, plastic
laminates, etc. Also see corner bead.

outside corner molding

688

overfire air

outside facing See outside casing.

outside finish, exterior finish The surface
treatment or decorative trim on the exterior of a

building.

outside foundation line A line indicating the
location of the outer side of a foundation wall.

outside glazing External glazing installed from
outside of the building.

outside gouge A gouge which has a bevel
ground on the convex side of its cutting edge.

outside lining See outside casing.

outside string Same as outer string.

outside studding plate In wood-frame con-
struction, a soleplate or a double top plate, usu-
ally the same size as the studding.

outside thread A thread on the external sur-
face of a pipe or cylinder.

outstanding leg One of the legs of a structural
angle member; usually not connected to another
structural member.

out-to-out measurement A measure of the
outside-to-outside distance across a piece.

out-turn cost (Brit.) The final cost of a build-
ing project.

outwindow A projecting loggia or the like.

oval A marble chip which has been tumbled
until a smooth oval shape has resulted; used for
terrazzo concrete.

oval 'window A window having the shape of an
ellipse or a shape between an ellipse and a circle.

ovendry wood, bone-dry wood Wood from
which no moisture can be removed when
exposed to a temperature of 212°F (100°C).

overall, overall dimension A total outer
dimension of a building material, including any
projection, such as a tongue.

overbreak Any excavation beyond the limits
set by the neat line.

overburden l.The entire thickness of soil
over rock or over a specific bearing stratum. 2.
An undesirable top layer covering rock, gravel,
or other useful material wanted for construction.

overcloak In sheet-metal roofing, the part of a
sheet that laps over an adjacent sheet beneath it.

overconsolidated soil deposit A soil de-
posit that has been subjected to an effective

pressure greater than the pressure of the present
overburden.

overcurrent An electrical current which is
abnormally high, usually as a result of a short
circuit.

overcurrent protection A form of protec-
tion in an electric circuit which prevents dam-
age resulting from excessive current; interrupts
the flow of current at a predetermined value.

overcurrent relay A relay used to provide
overcurrent protection.

overdesign As applied to structural design, a
design based on requirements higher than ser-
vice demands, usually as a means of com-
pensating for unknown and/or anticipated
deficiencies.

overdevelopment Excessive development of
a land area, neighborhood, or community.

overdoor, sopraporta A wall area, more or
less ornamented, directly above a doorway.

overdoor panel

overfire air Secondary air which is introduced
in a furnace above the grate to complete com-
bustion and to produce turbulence, thereby
increasing the efficiency of the combustion
process.

689

overfloor duct

overfloor duct A duct (usually fabricated of
metal) that is designed to house and protect
communications wiring across floor surfaces.

overflow, overflow pipe l.A pipe used to
remove excess water and/or to prevent flooding
in certain sanitary fixtures, storage tanks, and
plumbing fittings. 2. An outlet for a storage
tank; used to prevent flooding or to set the water
level in the tank.

OVERFLOW CHANNEL

overflow, 1
INLET PIPE

overflow, 2

overflow channel An overflow passageway
(forming an integral part of a fixture) which pro-
vides a means for removing excess water and
preventing overflow.

overflow drain A component in a roof
drainage system, used to protect the roof against
damage resulting from the water load imposed by
blocked or partially-blocked roof drains.

overglaze decoration A ceramic or metallic
decoration applied and fired on the previously
glazed surface of ceramic ware.

overgrain Regraining a grained, painted surface
to cause a deepening or exaggeration of the
grained effect.

overgrainer A special type of flat bristle brush,
with thin, long bristles, used in imitating the
natural grain of woods.

overhand work The laying of bricks in an
outer wall by bricklayers within the building,
standing either on a floor or on a scaffold.

overhang 1 . The projection of an upper story or
roof beyond a story immediately below. 2. See
jetty. 3. In a truss, the extension of the top chord
of a truss beyond the heel, measured horizon-
tally. 4. Same as overshoot.

overhaul The movement of excavated material
beyond a distance for which there are no
haulage charges.

overhead balance A type of balance for a
sash; installed in the head jamb of a window
frame; usually consists of a coiled steel tape under
spring tension.

overhead concealed closer A door closer
concealed in the head of a doorframe; has an arm
which connects with the door at the top rail.

overhead concealed closer

overhead door A door, of either the swing-up
or the roll-up type, which, when open, assumes a
horizontal position above the door opening; may
be a single leaf or constructed of several leaves;
often used as a door on a garage.

690

overthrow

overhead entrance conductor A service
entrance conductor between (a) the terminals of
service equipment and (b) a point usually outside
(and clear of) the building, where it is spliced to
an overhead service conductor between the last
pole and the premises served.

overhead expense An indirect expense.

overhead shovel A tractor having a shovel
which digs at the front end and dumps its load at
the rear end; often used in confined areas.

overhead-type garage door See overhead
door.

overhung door A door that opens outward
and is hinged along the top.

overhung impeller pump A centrifugal
pump whose impeller is mounted on the end of a
shaft that overhangs its bearings.

overjacket See jacket.

overlapping astragal, wraparound astragal
A vertical molding attached to the meeting edge
of one leaf of a pair of doors as protection against
weather and to minimize the transmission of
smoke, light, etc., between the doors.

overlapping astragal

overlay flooring Same as strip flooring.

overlay glass See cased glass.

overlight A horizontal rectangular light, 2 directly
above a door.

overload l.A load on a structure in excess of
that for which it was designed. 2. Electric cur-
rent, power, or voltage in excess of that for
which a device or circuit was designed.

overload capacity The overload, 2 which, if
exceeded, will result in permanent damage to
the equipment considered.

overload protector A device that interrupts
the flow of current in an electric circuit if the flow
becomes sufficiently high to constitute a danger.

overload relay A relay in the circuit of a motor
which causes the motor to be disconnected from
its source of power if the current to the motor
exceeds a predetermined value.

overmantel An ornamental panel or structure
above a mantelpiece. When Victorian architec-
ture was popular, a mirror was often set in the
overmantel to reflect light into the room from a
candelabra placed on the mantelpiece.

overpanel A non-transparent panel, 4 above a
door.

oversail To project beyond the general face of a
construction.

oversailing A term descriptive of a surface that
projects beyond the general face of the wall
immediately below. For example, an oversailing
course of brickwork projects beyond the general
face of a wall; an oversailing gable end is a gable end
that overhangs the floor immediately below it.

oversailing course A masonry course which
projects beyond the general face of a wall.

oversanded Descriptive of mortar or concrete
containing more sand than necessary to produce
adequate workability and a satisfactory condi-
tion for finishing.

overshoot The projection of an upper story
beyond the wall of the story below, commonly
on the front of the house but sometimes on the
sides as well; frequently called a jetty. Also see
framed overhang and hewn overhang.

overshot Same as jetty.

oversite concrete An underlayer of concrete
below a slab or other flooring; so placed to pre-
vent disturbance of the ground below, to provide
a relatively even and firm surface for the place-
ment of the next layer, and to keep out ground
air and moisture.

oversize brick 1. A brick whose dimensions
are 2.5 in. by 3.5 in. by 7.5 in. (6.4 cm by 8.9 cm
by 19.0 cm). 2. A brick whose dimensions are
larger than those given in definition 1 .

overstory 1 . An upper floor. 2. Same as clerestory.

overstretching The stressing of steel tendons
to a value higher than designed for the initial
stress; this is done (a) to overcome frictional
losses, (b) to overstress temporarily the steel to
reduce creep in the steel which occurs after
anchorage, and (c) to counteract the loss of pre-
stressing force that is caused by the subsequent
prestressing of other tendons.

overthrow A panel of ornamental metalwork
placed like a lintel above metal gates.

691

overtime

overtime The number of hours worked on a
building project in excess of the number agreed
upon for any single day or for any one week.

over»tone In painting, same as mass color.

overturning Failure of a retaining wall as a
result of pressure of the earth, which overcomes
the stability of the wall; the resistance to over-
turning is directly proportional to the weight of
the wall and the width of the base.

overvibration Excessive use of vibrators dur-
ing placement of freshly mixed concrete, causing
segregation and excessive bleeding.

OVHD On drawings, abbr. for "overhead."

ovolo A convex molding, less than a semicircle
in profile; usually a quarter of a circle or approx-
imately a quarter-ellipse in profile.

ovolo

ovum In classical architecture and derivatives,
an egg-shaped ornamental motif.

owlhole An opening in an exterior wall of a
barn that permits mice-eating birds such as owls
or martins to enter; often cut in a distinctive or
decorative pattern near the top of a gable end.

owner 1. The architect's client and party to the
owner-architect agreement. 2. One who has the
legal right or title to a piece of property.

owner-architect agreement A contract be-
tween the architect and client for professional
services.

owner-contractor agreement A contract
between the owner and contractor for a con-
struction project.

owner's inspector A person employed by the
owner to inspect construction in the owner's
behalf.

owner's liability insurance Insurance which
protects the owner against claims arising from his
ownership of property and which may be extended

to cover claims which may arise from operations of
others under the construction contract.
owner's manual An assemblage of all draw-
ings, warrantees, and submittals that provide the
information required to operate and maintain a
building and the equipment within it.

oxeye A bull's-eye, 2.

oxeye molding A concave molding less hol-
low than a scotia but deeper than a cavetto.

oxeye window, oxeye Same as bull's-eye
window.

oxidation Reaction of a chemical compound
with oxygen, as in a paint film in which oil
reacts with oxygen to form a hard dry film.

oxidized asphalt Same as blown asphalt.

oxidized sludge Sewage in which the organic
matter has been combined with oxygen and has
become stable.

oxter piece An upright timber used in ashlaring.

oxyacetylene torch A torch utilizing the
flame produced by the combustion of acetylene
with oxygen.

oxyacetylene welding A welding process
utilizing heat from a gas flame produced by the
combustion of acetylene and oxygen.

oxychloride cement, sorel cement A

strong, hard cement composed of magnesium
chloride and calcined magnesia; sometimes
fillers are added.

oxygen cutting A metal cutting operation in
which the separation of the metal is effected by
chemical reaction, between oxygen and the
metal, at a high temperature.

PREHEAT ORIFICES

CUTTING OXYGEN

ORIFICE

oxygen cutting tip

oxygen starvation Localized corrosion of
metals in the presence of an electrolyte, due to a

692

ozone lamp

smothering or poultice action or resulting from a discharges and by ultraviolet energy; used as a

crevice between metal parts or between the deodorant and to control mildew, fungus, and

metal and another material. bacteria; excessive amounts are harmful to

oyelet,oylet Same as eyelet. human tissue.

... . „ „ ozone lamp An electric-discharge lamp which

oz Abbr. tor ounce. emits minute quantities of radiant power at a

ozone An unstable form of oxygen that is a wavelength of 184-9 nanometers, producing

powerful oxidizing agent; produced by electric ozone.

693

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P 1. On drawings, abbr. for "page." 2. Abbr. for
"pole."

Pa Symbol for pascal; a unit of pressure.

P&G Abbr. for "post and girder."

P&T Abbr. for "post and timbers."

PIE Abbr. for "planed one edge."

PIS Abbr. for "planed one side."

P1S2E Abbr. for "planed one side and two
edges."

P4S Abbr. for "planed four sides."
PA On drawings, abbr. for public address system.
pace A seldom-used term for stair landing.
Pacific red cedar See thuya.
packaged air conditioner See room air con-
ditioner.

packaged attenuator Same as sound attenu-
ator.

packaged boiler A boiler unit having all com-
ponents including boiler, burner, controls, and
auxiliary equipment assembled as a unit.

packaged building See manufactured build-
ing and precut building.

packaged concrete A concrete mixture of
dry ingredients in a package; requires only the
addition of water to produce concrete.

package deal See turn-key job.

package dealer A person or organization
assuming responsibility under a single contract
for the design and construction of a project to
meet the specific requirements of another.

packaged fan equipment See air-handling
unit.

packaged house A prefabricated house com-
posed of building components cut to size at the
factory and/or manufactured components that
are commercially available.

package stability The ability of a liquid, such
as paint or varnish, to retain its original quality
after prolonged storage.

package trim Factory-made door and window
trim, ready for installation; delivered to the job-
site in packages.

packed chord A composite chord, 1 which
consists of several longitudinal structural mem-
bers that are bolted together.

packer 1. A device, usually expandable, which
is inserted into a hole to be grouted; prevents
return of the grout around the injection pipe.
2. Same as compactor, 2.

packing 1. The stuffing or a thin ring of elastic
material around a shaft or valve stem, or around
a joint, to prevent fluid leakage. 2. Small stones
embedded in mortar; used to fill the cracks
between the larger stones.

packing piece, stool A block which is used to
raise one or more members above others.

pack set The condition induced in stored
cement (whether in stationary containers or
during bulk shipment) of reduced ability to flow
freely; usually caused by interlocking of parti-
cles, by mechanical compaction, or by electro-
static attraction between particles.

pad See padstone.

padauk A hard, heavy wood, red with black
stripes, from India; used in cabinetmaking and
veneer.

paddle A flat plastering tool used to clean out
or to finish an angle or corner.

paddle mixer A mixer for concrete or mortar
having power-operated mixing blades which
revolve about an axis.

paddock A small field near a house or barn in
which animals, usually horses, are enclosed.

pad foundation An isolated, concrete slab on-
grade, 1 that serves as a foundation.

pad-mounted transformer A transformer
designed to be mounted directly on a pad foun-
dation with high- and low-tension cables coming
directly into the terminal compartments which
are part of the transformer housing.

695

pad saw

pad saw A small compass saw.

padstone, pad A strong block bedded on a
wall to distribute a concentrated load; a tem-
plate, 2.

pad support In an acoustical ceiling assembly
with a perforated metal pan, a device (such as a
wire grid) for holding the sound-absorptive ele-
ment out of contact with the perforated pan.

page A short thin wedge.

PageFormat A page organization for specifica-
tions as set forth by the Construction Specifica-
tions Institute.

pagoda A multistoried shrine-like tower, origi-
nally a Buddhist monument crowned by a stupa.
Stories may be open pavilions of wood with bal-
conies and pent roofs (prevalent in Japan) or
built-in masonry, of diminishing size with cor-
beled cornices.

paillasse Same as palliase.

paillette In decorative work, a bit of metal or
colored foil used to obtain a jeweled effect.

paillon Bright metal foil, used to show through
a thickness of enamel or paint to alter its color
and give it brilliance.

pai-lou, pai-loo A monumental Chinese arch
or gateway with one, three, or five openings;
erected at the entrance to a palace, tomb, or pro-
cessional way. Usually built of stone in imitation
of wood construction.

pai-lou at Amoy

paint A liquid solution of pigment in a suitable
vehicle of oil, organic solvent, or water; liquid
when applied but dries to form an adherent, pro-
tective, and decorative coating. Often categorized
according to the solvent used for thinning, for
example, water-thinned paint or solvent-thinned

paint. Also see acrylic paint, cement-water paint,
epoxy paint, latex paint, synthetic rubber-base
paint, vinyl paint, water-based paint.

paint base The vehicle into which pigment is
mixed to form a paint; commonly alkyd, latex,
acrylic.

paint bridge A platform or gallery, of fixed or
adjustable height, beside or above the stage of a
theater or in a paint loft; esp. used to paint
scenery.

paint brush A tool for applying paint, consist-
ing of a flexible brush composed of long filamen-
tary material bound to a handle.

paint drier See drier.

painted glass A decorative glass that is colored
by the application of an enamel paint onto a
glass surface that is then heated in a kiln at a
high temperature; see stained glass.

Painted Lady style A mode of 19th-century
Victorian architecture in which the exteriors of
houses are characterized by bright, contrasting
colors; San Francisco has an abundance of such
houses.

painter's putty See putty.

paint frame A movable frame, which can be
raised or lowered, used to hold stretched canvas
(and/or "flats") on which stage scenery is being
painted.

paint kettle, paint pot An open can with a
bail (wire handle) for carrying or hanging on
ladders while painting.

paint loft In a theater, a narrow vertical loft
containing paint frames and/or paint bridges.

paint oil See drying oil.

paint pad A tool for applying paint, consisting
of short filament material or an open-cell
resilient material which is connected to a han-
dle; designed to apply paint by a wiping action.

paint remover A liquid which is applied to a
dry paint or varnish to cause it to soften or lose
adhesion so that it may be removed easily.

paint roller A cylindrical tube which is coated
on the outside with nonwoven fibers such as
nylon, mohair, and lamb's wool and mounted on
a roller with a handle; used for application of
paint or varnish.

paint spray booth See spray booth.
paint sprayer See spray gun.

696

pallet

paint system The surface coating on a painted
object; built up from some combination of the
following coats: sealer or primer, stain, filler,
undercoat, topcoat, varnish coat.

paint thinner See thinner.

paired brackets Two closely spaced brackets
that form a pair; also called coupled brackets.

paired gables A facade having two gables that
form a pair; for example, sometimes found in the
facades of Gothic Revival structures of wood
construction.

palaestra A Greek or Roman building for ath-
letic training, smaller than a gymnasium, con-
sisting of a large square court with colonnades,
rooms for massage, baths, etc.

palazzo In Italian cities, a large, separate
dwelling, often lavish; one of the major categories
into which the Italianate style is often divided.

Palazzo style See Italian Renaissance Revival
in which palazzi were widely imitated.

paldao See dao.

pale 1. A flat strip (slat) or round stake, usually
of wood; set in series to form a fence. 2. An area
enclosed by such stakes.

pale-bodied oil See boiled oil.

pale brick Same as salmon brick.

palestra Same as palaestra.

paling See pale.

palisade A series of stout poles, pointed on top
and driven into the earth, used as a fence or for-
tification. Also see stockade.

palisado house A primitive house or building,
usually built in frontier areas; walls were once
constructed by setting two parallel rows of logs
upright into the ground, and then filling the
space between the rows with mud and twigs, or
clay mixed with stones.

palisander See Brazilian rosewood.

palladiana See berliner.

Palladian dormer A dormer having a win-
dow, divided in three parts, that is suggestive of
a small Palladian window.

Palladian door A door topped with a
rounded arch; flanked by vertical rectangular
areas of fixed glass on each side that are nar-
rower and usually not as high as the door; sug-
gestive of the appearance of a Palladian
window.

Palladianism A term descriptive of a style of
building that follows the strict use of Roman
forms, as set forth in the publications of the Ital-
ian Renaissance architect Andrea Palladio
(1508-1580), particularly under the influence of
Lord Burlington in the 18th century.

Palladianism

Palladian motif, Serlian motif, Venetian
motif A door or window opening in three
parts, divided by posts, with a lintel flat over
each side but arched over the center.

Palladian Revival See Anglo-Palladianism.

Palladian window A large window divided in
three parts: a central sash that is arched at the
top and two sashes on each side of it that are
smaller than the central sash; the smaller sashes
are rectangular, topped with flat lintels. Compare
with three-part window. (See illustration p. 698.)

pallet 1. A flat piece of wood laid in joints of
brickwork to allow fastening of woodwork to

697

pallet brick

palm capital

Palladian window

pallet, 2

palmette

wall. 2. A portable platform used to facilitate
handling by a forklift.

pallet brick, pallet slip A brick esp. made with
a groove along one edge to receive a pallet, 1.

palliase In masonry, a supporting bed.

palma cottage A primitive one-room dwelling
having a steeply-pitched gable roof which is
thatched with overlapping palmetto fronds
attached to a wood framework; provides a rela-
tively watertight roof and walls. Temporary
dwellings like these were constructed by early
Spanish colonists in Florida.

palmate l.A column capital resembling the
leaves of a palm tree. 2. A palmette.

palm capital A type of Egyptian capital resem-
bling the spreading crown of a palm tree.

palmette An ornament derived from a palm leaf.

palmiform Having the form of a palm leaf or

the crown of a palm tree.
pamment A thin square paving brick.

pampre An ornament consisting of vine leaves
and grapes used to fill cavettos and other contin-
uous hollows in a group of moldings.

pan 1 . A wall plate. 2. A part of an exterior wall;
esp. in half-timbered construction, the wall
spaces between the timbers. 3. A major vertical
division in a wall. 4. A structural panel. 5. A
form, frequently of molded fiberglass, used in
pouring concrete floors or roofs. 6. The re-cessed
bed for the leaf of a hinge.

panache The curved surface of a pendentive.

pan-and-roll roofing tile Single-lap roofing
tile of two types used in combination: a flat,
tapered undertile having flanges, and a half-
rounded tapered overtile.

pan breeze, breeze Small bits of coke and fur-
nace clinker from the pan beneath a coke oven;
suitable for use as aggregate in lightweight con-
crete block.

pancarpi Garlands or festoons of flowers, fruits,
etc.

698

panel house

pan construction A concrete floor or roof
construction in which a prefabricated form (pan,
5) is used repeatedly, giving the underside of the
construction a waffle-like appearance.

pan construction section view

pane 1. A flat sheet of glass, cut to fit a win-
dow or door or part of a window or door; often
of small size, the larger ones usually being
called sheets. After installation in a window
sash, a pane is often referred to as a light. A win-
dow sash may be divided into a number of small
lights, often for decorative or stylistic purposes.
The configuration of a double-hung window
having divided lights is often specified by the
number of panes in the upper sash followed by
the word over and then the number of panes
in the lower sash; for example, a "six-over-three
pattern" indicates that the upper sash is divided
into six panes and the lower sash is divided
into three panes. 2. A panel of a door, wain-
scot, or the like. 3. A rectangular division or
plane surface of a building. 4. A British term
for peen.

panel 1 . A large, relatively thin board or sheet
of lumber, plywood, or other material used as a
wall covering. 2. A thin board, plywood sheet,
or similar material with all its edges inserted in
a groove of a surrounding frame of thick mate-
rial. 3. A portion of a flat surface recessed or
sunk below the surrounding area, distinctly set
off by molding or some other decorative
device. 4. A section of floor, wall, ceiling, or
roof, usually prefabricated and of large size,
handled as a single unit in the operations of

assembly and erection. 5. A length of formed
metal sheet, or an assembly of such sheets, usu-
ally with insulation between, as used for wall
enclosure on industrial-type buildings. 6. A
frog. 7. That portion of a truss between adja-
cent panel points lying in the same chord. 8.
Same as panelboard.

panel board l.In an electrical installation, a
single panel or group of panel units designed for
assembly in the form of a single panel; includes
buses, and may include switches as well as auto-
matic overcurrent protective devices for the
control of electric circuits; designed to be placed
in a cabinet or cutout box placed against a wall
or partition so that it is accessible from the front
only. 2. See control board.

panel box A small panel board providing many
of the same functions as a larger panel board.

panel construction, panellized construc-
tion A method of building construction
which uses panels as major elements or compo-
nents.

panel divider A molding which separates two
wood panels along their common edge.

panel divider

and

-*- PAN EL*

panel, 7; panel point

panel door A door having stiles, rails,

sometimes mutins which form one or more
frames around (thinner) recessed panels. (See
illustration p . 700.)
paneled door Same as panel door.

panelescent lamp See electroluminescent
lamp.

panel heating A system for heating a room or
space by panels (in the walls, floor, ceiling, or
along the baseboard) in which there are electric
heating elements, hot-air pipes, or hot-water
pipes.

panel house A brothel in which the rooms are
lined with sliding panels which facilitate rob-
beries of house patrons.

699

paneling

panel door

paneling A wall or ceiling treatment made up
of panels, 4.

paneling

panel molding A molding surrounding a
panel. See also bolection molding, drop molding.

panel pin A very slender wire nail with a small
head; usually used in finished work.

panel point, node A point where members of
a truss intersect.

panel radiator A radiator which is set into a
wall panel or baseboard.

panel saw A small saw having closely set teeth;
used in cutting thin panels and the like.

panel strip A narrow piece of metal or wood
used to conceal a joint between two sheathing
boards forming a panel.

panel tracery Same as perpendicular tracery.

panel wall A non-load-bearing wall between
columns or piers in skeleton construction; such
walls are supported at each story by the building
frame.

panelwork Same as paneling.

panework 1. In Tudor Revival, the decorative
panels formed by half-timbering. 2. Same as
pane, 3.

pan fraction In the sieve analysis of aggre-
gate, soil, etc., that fraction of the total sample
retained on any sieve compared with the initial
sample tested.

panhead rivet A rivet having a head whose
shape is that of a truncated cone.

panic bolt See panic exit device.

panic exit device, fire-exit bolt, panic bolt,
panic hardware A door locking device used
on exit doors; the door latch releases when a bar,
across the inside of the door, is pushed.

panel insert A metal panel usually used to con-
vert a half-glass recessed panel-type door to an
all-metal unit.

panel lamp A small lamp or a luminaire used
to provide local lighting on instrument panels
and the like.

panel length In a truss, the distance between
two adjacent joints along either the upper or the
lower chord.

panel lining 1. Door lining having panels simi-
lar to those on the door. 2. Lining around a win-
dow frame which matches the sash paneling.

panel load The load at a panel point of a truss.

panel mold See pan mold.

s 6

panic exit device

panic hardware See panic exit device.
panic latch See panic exit device.

panic switch An electric switch that controls
a security lighting system in a home; often
located in the master bedroom.

700

p.a.r.

panier See corbeil.

pan mixer See open-top mixer.

pan mold, panel mold A mold used to cast
plaster panels.

pannier Any basketlike architectural member,
once especially applied to capitals resembling
baskets.

panopticon A building (often a jail) planned
with corridors which radiate from a single, cen-
tral point. A person located at the central point
can observe each of the converging halls.

panorama A building containing an exhibit of
an extended pictorial representation of land-
scape or some event of note; usually depicted of
a large, wide area.

pantheon l.A temple dedicated to all the
Gods. 2. (Cap.) The Rotunda in Rome, formerly
a temple to all the gods, now a church. 3. The
Pantheon in Paris, the former church of Sainte-
Genevieve, now a shrine to national heroes.

pantheon, 2

pantograph

pan-type humidifier A shallow pan having a
relatively large area, filled with water which
evaporates as air passes over the pan; a heating
element in the pan may be used to increase
evaporation.

pan-type tread A section formed from sheet
metal to receive a fill and to provide, when filled,
either a tread or a combination tread and riser.

pap A downward outlet from an eaves gutter.

paper-backed lath Any lath having a paper
backing.

paper felt A type of building paper.

paper form A form for concrete made of a
heavy paper material.

papier-mache A material composed princi-
pally of paper; usually prepared by pulping a mass
of paper (sometimes glue is added) to a dough-
like consistency and molding to a desired form.

papyriform A capital of an Egyptian column
having the form of a cluster of papyrus flowers.

pantile A roofing tile which has the shape of an
S laid on its side.

W.£M.Mii"i

pantile

pantograph A drafting instrument for copying
drawings, plans, etc., either on the same scale or
on an enlarged or a reduced scale.

pantry 1. A serving room between kitchen and
dining space. 2. A room for storage of food sup-
plies; a larder. 3. A room for preparing refresh-
ments, not complete meals.

papyriform

papyrus column A column having a papyri-
form capital.
p.a.r. Abbr. for "planed all round."

701

PAR

PAR See PAR lamp.

PAR. On drawings, abbr. for paragraph.
parabema Same as diaconicon.

parabolic arch An arch similar to a three-cen-
tered arch but whose intrados is parabolic, with a
vertical axis.

parabolic reflector A light reflector whose
surface is a paraboloid, i.e., a surface generated
by rotating a parabolic section about its axis; if a
small light source is placed at the focal point of
the reflector, the reflected light will be concen-
trated in a nearly collimated beam parallel to the
axis of the reflector.

parabolic vaulting A type of vaulting, para-
bolic in shape, usually constructed of a relatively
thin, lightweight, reinforced concrete; not sub-
ject to tensional stresses under conditions of uni-
form loading.

paracyl reflector A cylindrical light reflector
whose cross section is that of a semicircle joined
to part of a parabola; they are joined so that the
focus of the parabola is the center of the semicir-
cle, at which point a linear light source is placed;
esp. used for wall-washing.

paradise 1 . The court of the atrium in front of a
church. 2. The garth of a cloister. 3. A Persian
pleasure garden, usually elaborately planted.

paradisus Same as paradise.

parados 1. An entrance to the orchestra, 1 of a
Greek theater. 2. Earthworks behind a fortified
place.

paragraph In the AIA documents, the first
subdivision of an article, identified by two
numerals, e.g., 3.3; may be further subdivided
into subparagraphs and clauses.

parallel-blade damper A damper, 1 through
which the airflow is adjusted by means of
damper blades on a common linkage, arranged
so that adjacent blades rotate parallel to each
other, providing little control of airflow; used
primarily as an on-off control.

parallel-chord truss See flat-chord truss.

parallel coping A coping which is flat, not
sloped to shed water.

parallel gutter See box gutter.

parallel stair A stair consisting of flights which
parallel each other and are separated only by one
or more intermediate platforms.

parallel-blade damper

parallel-wire unit In posttensioning, a tendon
which is composed of a number of strands (or
wires) that are approximately parallel.

parapet 1. A low guarding wall at any point of
sudden drop, as at the edge of a terrace, roof, bat-
tlement, balcony, etc. 2. A defense wall. 3. In an
exterior wall, fire wall, or party wall, the part
entirely above the roof.

parapeted gable A gable having a face that
rises above the cornice line and carries a parapet;
for examples, see corbie gable, Flemish gable,
mission gable, multicurved gable, straight-line
gable.

parapet gutter A gutter which is constructed
behind a parapet wall.

parapet skirting Roofing felt which is turned
up against a parapet wall.

parapet wall That part of a wall which is
entirely above the roof.

para red A class of organic red and maroon dyes
and pigments; used in paints.

parascenium A wing-like projection extend-
ing forward, at the ends of the skene, in ancient
Greek theaters.

paraskenion Same as parascenium.

parastas 1. The end of a wall, terminating in an
anta, such as that enclosing the pronaos of a
temple. 2. A pedestal-like wall, as the abutment
of the end of a monumental stairway.

paratorium The place at the east end of a
basilican church, usually on the north side, for

702

parkerized

the offerings; in some Greek churches, located
on the south side.

paratory In a church, a place where any prepa-
ration is made; a vestry or sacristy.

parcel Of land, a contiguous land area which is
considered as a unit, which is subject to a single
ownership, and which is legally recorded as a
single piece.

parclose, perclose l.In medieval churches
and derivatives, a screen dividing a special space
from general space. 2. The parapet round a
gallery.

parecclesion A chapel of a Byzantine church.

parent material The material from which a
soil has been formed.

paretta Rough-cast masonry having a surface of
protruding pebbles.

parge To apply a parge coat; also see parget, 3.

parge board Same as bargeboard.

parge coat, pargeting, pargework 1. Elabo-
rate plasterwork; especially an ornamental facing
for plaster walls decorated with figures in low
relief. 2. The interior lining of a chimney flue
used to improve its fire protection and to provide
a smooth surface. 3. A coat of cement mortar on
the face of rough masonry construction.

parget, pargeting, pargetting, parge-
work, parging 1. Elaborate plasterwork;
esp. an ornamental facing for plaster walls,
sometimes decorated with figures in low relief

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applying a parget, 3

or indented; often used on the exterior of
houses in the Tudor period. 2. An interior lin-
ing of a flue to provide a smooth surface and to
aid in fire protection. 3. In masonry construc-
tion, a coat of cement mortar (generally con-
taining dampproofing ingredients) on the face
of rough masonry, the earth side of foundation
and basement walls, or the like; a parge coat.

Parian cement, Parian plaster Similar to
Keene's cement, but contains borax as an addi-
tive in place of alum.

paries In ancient Roman construction, a wall of
a house or other edifice. Also see murus.

paring Trimming or reducing in size or thick-
ness, by cutting or shaving of small portions from
the surface or extremity.

paring chisel A long-handled chisel used for
cutting away wood by hand alone, not by strik-
ing with a mallet.

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parget, 1

paring chisel

paring gouge A long, thin, concave gouge for
woodworking which is beveled on its inner edge.

Paris blue See Prussian blue.

parish house A building for the secular activi-
ties of a parish.

Paris white Same as whiting.

park An area, usually of public land set aside for
recreation and leisure, usually owned and managed
by a municipality, a state, a nation, or held by royal
grant, or in some cases by private organizations.

parkerized Descriptive of iron or steel which
has received a rustproofing treatment by being

703

Parker's cement

dipped in a boiling solution of manganese di-
hydrogen phosphate; this protective coating
also improves the bonding of paints and lac-
quers.

Parker's cement Same as Roman cement.

Parker truss A type of truss whose upper
chord, 1 is polygonal in form.

parking garage A garage for passenger vehi-
cles only, exclusively for the purpose of parking
or storing of automobiles and not for automobile
repairs or service work.

parking lot, car park An area set aside for
parking motor vehicles. The net area of a park-
ing facility is the area devoted to parking places
and circulation aisles. In a multi-story parking
facility the gross area also includes the building's
service cores and exit stairs.

parking space A marked-off portion of a park-
ing area for short-time storage of a single motor
vehicle.

parking structure l.A building for short-
term storage of motor vehicles, having two or
more tiers or levels and at least two open sides,
and with the top tier either roofed or not. 2. A
machine for automatic short-term storage of
motor vehicles.

parking tier One of several levels or stories
devoted to the temporary storage of motor
vehicles.

PAR lamp A reflector lamp, usually incandes-
cent, with a thick glass envelope, the back interior
side of which has a parabolic shape with a reflec-
tive coating; used with a lensed front of the enve-
lope to provide desired spread of the light beam.

PAR lamp

parlatory A room in a monastic establishment

where visitors may be received.
parliament hinge See H-hinge.

parlor 1. In a house, a room primarily for enter-
taining and conversing with guests. 2. In a hotel,
a room for receptions.

parlor chamber A bedroom above the parlor in
a two-story house having a hall-and-parlor plan.

parodos One of the two side entrances to an
ancient theater between the seats and the stage;
used principally by the chorus, but also by the
public.

parpend A little used synonym for perpend.

parpend stone See perpend.

parquet 1. Inlaid wood flooring, usually set in
simple geometric patterns. 2. Same as parquetry.
3. The lower floor of a theater, or the section of
seats in an opera house, music hall, or theater
extending from the musicians' area to the par-
quet circle.

parquet circle, orchestra circle, parterre

In a theater or opera house, the part of the main
floor at the rear of the parquet, 3, usually under
the galleries or balconies.

parquetry A flat inlay pattern of closely fitted
pieces, usually geometrical, often employing two
or more colors or materials; used for ornamental
parquet flooring or wainscoting, in stone or wood.

parquet strip flooring Same as strip flooring.

parrel, chimney breast A chimneypiece or
the ornaments of a chimneypiece collectively.

parsonage The residence of a parson, provided

by the church.
part Abbr. for partition.

parterre 1. See parquet circle. 2. An ornamen-
tal arrangement of flower or gravel beds of vari-
ous sizes and shapes.

Parthenon 1. Originally, the room behind the
cella in the great temple of Athena Parthenos
on the Athenian Acropolis. 2. More commonly,
the name of the entire temple.

Parthian architecture An architectural style
developed under Parthian domination (3rd cent.
B.C. to 3rd cent. A.D.) in western Iran and
Mesopotamia, combining classical with autoch-
thonous features. Its major achievement is the
monumental iwan covered by a barrel vault in
stone or brick.

parti A scheme or concept for the design of a
building.

partial cover plate A cover plate, 1 attached
to the flange of a girder which does not extend
the full distance between the supports of the
girder.

704

parting strip

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Parthenon, 2

partial-height partition In an open-plan of-
fice, a free-standing partition which provides
visual privacy and some (but usually little)
sound attenuation between adjacent offices.

partial occupancy Occupancy by the owner
of a portion of a project prior to final completion.

partial partition See partial-height partition.

partial payment A progress payment.

partial prestressing The prestressing of con-
crete to a level of stress such that tensile stresses
exist in the precompressed tensile zone of the
prestressed member, for design loads, 1 .

partial release In a prestressed concrete
member, a release of part of the total prestress
initially held entirely in the prestressed rein-
forcement.

particleboard A large class of building boards
made from wood particles and a binder; usually
has a density of 25 to 50 lb per cu ft (400 to 800
kg per cu m); often faced with veneer. Also see
chipboard; coreboard.

particle shape The shape of a particle of aggre-
gate. Also see angular aggregate, cubical aggre-
gate, elongated piece, flat piece.

particle size 1 . In evaluating the efficiency of a
filter for removing particles from an air stream,
the minimum particle diameter in microns that
will be removed by the filter. 2. In paints, the

diameter of a pigment or latex particle; usually
expressed in mils or microns.

particle-size distribution A tabulation of the
percentages of the various sizes of particles in a
sample of soil or aggregate for concrete as deter-
mined by sieve analysis.

particulate grout A grouting material which is
characterized by undissolved particles in the mix.

parting agent A material applied to one or
both surfaces of a sheet to prevent adhesion to
other sheets; a release agent.

parting bead A long narrow strip between the
upper and lower sashes in a double-hung window
frame, enabling them to slide past each other;
also called parting stop, parting strip.

PARTING
BEAD

parting bead

parting compound A parting agent.

parting lath A parting strip made of wood lath.

parting slip, midfeather, wagtail A long
thin strip of wood in the box jamb of a cased
frame which separates the sash weights from each
other; also called a parting strip, parting bead.

parting stop See parting bead.

parting strip l.A narrow strip used to keep
two parts separated, such as a parting slip. 2. A
parting bead.

705

parting tool

parting tool, V-tool A narrow-bladed hand
tool having a V-shaped gouge; used in wood-
working for cutting grooves, in wood turning, or
for cutting pieces in two.

parting wall Same as party wall.

partition 1. A dividing wall within a building;
may be bearing or non-load-bearing. 2. In
sound-transmission considerations, any building
component (or a combination of components),
such as a wall, door, window, roof, or floor-ceil-
ing assembly, that separates one space from
another.

partition block A concrete masonry unit for
use in non-load-bearing walls; usually has solid,
rectangular end faces and a nominal thickness of
4 in. (10 cm) or 6 in. (15 cm).

partition cap, partition head, partition
plate The uppermost horizontal member of a
partition; the top plate of a partition on which
the joists rest.

partition head See partition cap.

partition infilling 1. Same as fill insulation. 2.
See infilling.

partition plate See partition cap.

partition stud See stud.

partition tile Tile for use in building interior
partitions, subdividing areas into rooms, or simi-
lar construction, carrying no superimposed loads.

partly cloudy sky In daylighting, a sky hav-
ing between 30% and 70% cloud cover.

partn Abbr. for partition.

parts per million The parts of a substance per
million parts (by weight) of a solution; equal to
0.0001%. Abbr. ppm.

party arch An arch on the line separating the
property of two owners.

party fence A fence that separates two proper-
ties.

party wall A wall used jointly by two parties
under easement agreement, erected upon a line
dividing two parcels of land, each of which is a
separate real estate entity; a common wall.

party-wall house Same as row house.

parvis 1 . The open square in front of a large
church. 2. An enclosed court or room in front of
a church. 3. A room over a church porch, 1.

pascal (Pa) The Standard International unit of
pressure; 1 pascal is equal to 1 newton per square
meter.

pas-de»souris In a castle, the steps leading
from the moat to the entrance.

pass A single progression of a welding operation
along a joint, resulting in a weld bead.

PASS. On drawings, abbr. for "passenger."

passage grave, chamber tomb In prehis-
toric Europe, a chamber approached by a long
passage, of megalithic construction, covered and
protected by an artificial mound.

passageway, passage A space connecting
one area or room of a building with another.

pass door A door through the proscenium wall,
from stage to the auditorium.

passenger elevator An elevator exclusively for
the use of passengers. Also see freight elevator.

passenger elevator car See elevator car.

passenger lift See elevator car.

passings The amount of overlap between sheets
of flashing etc.; same as lap, 2.

passion cross Same as Calvary cross.

passivation Treatment of a metal surface
which leaves a protective coating, rendering the
surface less reactive chemically.

passive lateral pressure The horizontal soil
pressure that is exerted upon a retaining struc-
ture by the soil that it retains.

passive solar energy system A building
subsystem in which solar energy is collected and
transferred predominantly by natural means;
uses natural convection, conduction, or radia-
tion to distribute thermal energy through a
structure, within the limits of the indoor design
temperature conditions. Compare with active
solar energy system.

pass»through 1. An opening in a partition for
passing things from one adjoining space to
another, usually between a kitchen and a dining
space in a dwelling, but also between any two
spaces in a building. 2. A provision in a lease
that makes the tenant, rather than the owner,
directly responsible for certain costs.

paste filler In painting, a filler, 3 in paste
form; usually thinned with solvent prior to
application.

paste paint A mixture of oil, pigment, and some
solvent in paste form; requires mixing with addi-
tional solvent and/or oil to produce a usable paint.

706

patina

pastiche A mixture of materials, forms, motifs,
and/or styles; often incongruous.

pastophorium, pastophorion In the early
church, one of the two apartments at the sides of
the bema or sanctuary; this arrangement has been
retained in the modern Greek Orthodox church.

pastoral column A tree trunk used as a col-
umn, for example, as used in cottage orne.

Pat. In the lumber industry, abbr. for "pattern."

pat As applied to a specimen of neat cement
paste, a sample about 3 in. (7.6 cm) in diameter
and Vi in. (1.3 cm) in thickness at the center and
tapering to a thin edge; applied on a flat glass
plate to determine the setting time.

patand See patten.

patch 1 . In stone masonry, a compound used to
fill natural voids or to replace chips and broken
corners or edges in fabricated pieces of cut stone;
applied in plastic form; mixed or selected to
match the color and texture of the stone. 2. In
carpentry and joinery, a piece of wood or veneer
glued into a recess to replace defective portions
or voids; an insert or plug.

patch board, patch panel A board or panel
where electric circuits are terminated with jacks
and plugs, and where they may be intercon-
nected temporarily by means of a cord called a
"patch cord."

patch panel See patch board.

patent board A building board manufactured
under a patented process.

patent glazing A system of glazing which
employs any of a variety of commercially avail-
able devices for securing the glass sheets without
the use of putty.

patent hammer A two-faced hammer, each of
whose faces is composed of a number of parallel
thin chisels; used for dressing stone.

masonry surface which has been tooled with a patent hammer

patent knotting In painting, a knot sealer; a
solution of shellac and benzine or similar sol-
vent. Also see knotting.

patent light Same as pavement light.

patent plaster l.A gypsum plaster that is
mixed with sand; used as a base-coat plaster. 2.
A plaster manufactured under a patent process
whose exact constituents are secret; a chemical
plaster. 3. Same as cement plaster.

patent plate Same as plate glass.

patent stone See artificial stone.

patera A roundel, often decorated with leaves,
petals, or the like; sometimes used as a decora-
tive element, such as on a corner block. Also see
rosette.

patent hammer

architectural paterae

paternoster A small round molding cut in the
form of beads like a rosary; a bead molding.

path A footway; a footpath.

patience Same as miserere.

patin See patten.

patina, patination 1. A greenish brown crust
which forms on bronze. 2. Any thin oxide film
which forms on a metal; often multicolored. 3. A
film, similar in color, which forms on a material
other than metal. 4. Such effects artificially
induced, or imitated. 5. A green coating on the
surface of copper or copper alloys that have been
exposed to the atmosphere for a long time.

707

patio

patio 1 . An outdoor area or courtyard, open to the
sky but enclosed, or partially enclosed, by the walls
of a building. Although the term originally
described such an area in a Spanish house, it is
now widely used for any outdoor recreational
space that is adjacent to a house; also see placita. 2.
A large quadrangle of an early Spanish- American
mission, usually surrounded on all four sides by a
series of abutting structures for protection.

patland In carpentry of the Early English
period, the sill or lower frame member.

patten, patand, patin l.The base of a col-
umn or pillar. 2. A base or a groundsill which
supports a column, post, or pillar.

pattern 1 . A model made in some easily worked
material (such as plaster or wood) which serves
as a guide, with respect to form and dimensions,
in laying out any piece of work, esp. to preserve
and secure uniformity and accuracy. 2. A design,
considered as a unit, of which an idea can be
given by a fragment, as a diaper pattern. 3. In
molding, a form used to provide the interior
shape of the mold.

pattern book In the 18th and 19th centuries, a
book on architectural practice that once served
as a builders' manual, builders' guide, or hand-
book containing plans and/or patterns of houses
and building details such as columns, cornices,
doors, porches, and windows.

pattern cracking Fine openings on concrete
surfaces in the form of a pattern; results from a
decrease in volume of the material near the sur-
face and/or an increase in volume of the material
below the surface.

patterned brickwork Masonry of bricks of
more than one color, direction, texture, or bond,
6, so as to form a decorative design.

patterned glass Glass that has a textured pat-
tern on one side (the other side being smooth).

pattern staining In plastering, dark areas, par-
ticularly on the interior side of exterior walls or
ceilings; results from different thermal conduc-
tances of the backings.

paumelle A type of door hinge having a single
joint of the pivot type, usually of modern design.

pavement The durable surfacing of a road,
sidewalk, or other outdoor area.

pavement base In a pavement, the layer
between the surfacing material and the subbase or
subgrade.

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paumelle hinge

pavement brick A square paving brick that is
relatively thin.

pavement light Heavy glass disks or prisms set
into a pavement to convey light to a space
beneath.

pavement saw A self-propelled machine,
equipped with a rotating blade, that cuts a narrow
kerf in a new concrete slab to provide a localized
joint for the control of cracking due to expansion.

pavement sealer See asphalt pavement sealer.

pavement structure All courses of selected
material placed on a foundation or subgrade soil,
other than layers or courses constructed in grad-
ing operations.

paver 1 . A paving stone, paving brick, or paver
tile. 2. A half-thickness paving brick, used as a
floor finish. 3. A self-propelled machine that
places concrete.

paver tile Unglazed porcelain or natural clay
tile, formed by the dust-pressed method; similar
to ceramic mosaic tile in composition and phys-
ical properties but thicker.

pavestone A paving stone.

pavilion 1. A detached or semidetached struc-
ture used for entertainment or (as at a hospital)
for specialized activities. 2. On a facade, a
prominent portion usually central or terminal,
identified by projection, height, and special roof
forms. 3. In a garden or fairground, a temporary
structure or tent, usually ornamented.

pavilion roof l.A roof hipped equally on all
sides, so as to have a pyramidal form; a pyramidal
hipped roof. 2. A similar roof having more than
four sides; a polygonal roof. 3. A steeply pitched
hipped roof whose upper termination is usually a
ridge somewhat shorter than the length of the
building.

pavimentum In ancient Roman construction,
a pavement formed by pieces of crushed stone,
flint, tile, and other materials set in a bed of

708

peak-load controller

ashes or cement and consolidated by beating
down with a rammer.

paving aggregate Materials such as crushed
stone, gravel, sand, slag, seashells, and mineral
dust, used in pavements.

paving asphalt A dark brown to black sticky
residue, predominantly derived from the refining of
crude oil; used as the binder in asphaltic concrete.

paving breaker, chipper A hand-held
compressed-air-powered tool for cutting pave-
ment or rock; delivers repetitive blows by
means of a pointed or chisel-shaped bit.

paving brick A vitrified brick, esp. suitable for
use in pavements where resistance to abrasion is
important; a pavior.

paving stone, pavestone A block or chunk
of stone, shaped or selected by shape for a paved
surface.

paving train An assemblage of equipment
designed to place and finish a concrete pavement.

paving unit Any prefabricated unit used for
surfacing the ground.

pavior, paviour 1. A brick used for paving. 2.
A clamp brick of second quality which is hard,
well-shaped, and of good appearance and color.

pavonaceum An ancient method of laying
tiles that are rounded at one end, so that in over-
lapping each other they present a scalloped
appearance.

pavonazzo, pavonazzeto 1. Various red and
purplish marbles and brescias. 2. A marble, used
by the ancient Romans, characterized by very
irregular veins of dark red with bluish and yel-
lowish tints.

pawn A covered passageway or gallery.

PAX On drawings, abbr. for "private automatic
(telephone) exchange."

payment bond A form of security purchased
from an insurance company, which provides a
guarantee that the contractor will pay the com-
plete costs of labor, materials, and other services
related to the project for which he is responsible
under the contract for construction.

payment request See application for pay-
ment.

payments withheld A provision in the Gen-
eral Conditions of a contract for construction
that permits the owner to withhold payments to

a contractor if the work specified in the contract
documents falls behind the schedule of con-
struction or if the work deviates from the speci-
fications.

PB stucco Abbr. for polymer-based stucco.

PBX See private branch exchange.

pc Abbr. for "piece."

PC l.Abbr. for portland cement. 2. Abbr. for
"power circuit." 3. On drawings, abbr. for
"piece." 4. On drawings, abbr. for "pull chain."
5. Abbr. for "Producers Council."

PCA Abbr. for "Portland Cement Association."
pcf Abbr. for "pounds per cubic foot."
PC stucco Abbr. for portland cement stucco.
PCSA Abbr. for "Power Crane and Shovel
Association."

p.e. Abbr. for "plain edged."

PE l.In the lumber industry, abbr. for "plain

end." 2. Abbr. for polyethylene.
P.E. Abbr. for professional engineer.
peacock's-eye Same as bird's eye.

pea gravel Small-diameter ( l A to V» in. or 6.4
to 9.5 mm) natural gravel, screened to specifi-
cation.

pea gravel grout A grout to which pea gravel
has been added.

peak arch A pointed arch.

peak demand The maximum rate of consump-
tion of water or electric power that a utility pro-
vides a customer.

peaked roof A roof of two or more slopes that
rises to a ridge or peak.

peak- head window 1. A window that has a
triangular head, such as a lancet window; often
found in Gothic Revival church architecture. 2.
Same as lancet window.

peak joint At the ridge of a roof, the joint
between members of a roof truss. (See illustration
p. 710.)

peak load The maximum load carried by a
device, system, or structure over a designated time
period.

peak-load controller An automatic electri-
cal monitor and controller which can be used
to limit the maximum power demands of a
building.

709

peak sound pressure

peak joint

peak sound pressure The maximum instanta-
neous sound pressure (a) for a transient or impul-
sive sound of short time duration, or (b) for a sound
of long duration, over a specified time interval.

pean See peen.

peanut gallery The topmost balcony in an
auditorium.

pear drop l.A pear-shaped pendant, often
used as a handle or support. 2. In 18th cent,
architecture, a support for a small arch.

pearl essence A translucent, lustrous pigment
obtained from fish scales or compounded syn-
thetically; used as a pigment in lacquers to
obtain a pearl-like finish.

pearlite Same as perlite.

pearl lamp British term for a frosted lamp bulb
which is etched on its inner surface.

pearl molding A molding decorated with a
continuous series of pearl-like shapes.

pearl molding

peat A fibrous mass of organic matter in various
stages of decomposition, generally dark brown to
black in color and of spongy consistency.

peat moss l.Moss entering into the composi-
tion of, or producing, peat; used as mulch. 2. The
debris of mashes and bogs, somewhat compressed
and partially decomposed; used as mulch.

pebble dash Same as rock dash.

pebble wall 1. A wall built of pebbles in mor-
tar. 2. A wall faced with pebbles embedded, at

random or in pattern, in a mortar coating on the
exposed surface.

peck In timber, decay resulting from fungus in
isolated spots.

pecked finished Same as picked finish.

pecking Same as salmon brick.

pecky timber, peggy timber Fungus-spot-
ted wood, such as pecky cypress or pecky cedar;
the decay stops when the wood is dried.

pectinated Having teeth like a comb.

pedestal 1. A support for a column, statue, urn,
etc., consisting in classical architecture of a base,
dado, or die and a cornice, surbase, or cap; in
modern design often a plain unornamented
block. 2. An upright compression member the
height of which does not exceed three times its
least lateral dimension.

cornice

pedestal

pedestal pile A cast-in-place pile which is con-
structed so that some concrete is forced out at
the bottom of the casing, forming a pedestal
shape at the foot of the pile.

pedestal urinal A urinal which is not con-
nected to the wall for support but is mounted on
a single pedestal.

pedestal washbasin A washbasin which is
supported from the floor by a column-like base.

pedestrian bridge See footbridge.

pedestrian control device Any device, esp.
a turnstile, but including a gate, railing, or post,
used to control or monitor the flow of pedestrian
traffic, to control access to a given area, etc.

pede 'window In a church, a window oriented
with respect to a larger one so as to symbolize
one of the feet of Christ.

710

pegboard

pediment 1. In Classical architecture, a triangu-
lar gable usually having a horizontal cornice, with
raked cornices on each side, surmounting or
crowning a portico or another major division of a
facade, end wall, or colonnade. 2. A gable above
or over a door, window, or hood; usually has a hor-
izontal cornice, crowned with curved sides, or
may also be crowned with another configuration
(such as broken sides) or its base may be broken in
the middle. For definitions and illustrations of
specific types, see angular pediment, broken ped-
iment, broken-scroll pediment, center-gabled
pediment, curved pediment, open pediment,
pointed pediment, round pediment, scroll pedi-
ment, segmental pediment, split pediment,
swan's-neck pediment, triangular pediment.

RAKING CORNICE

TYMPANUM

SPLIT FILLET

HORIZONTAL
CORNICE

pediment

pedimented dormer

pediment arch A miter arch.

peel, pele In northern England and Scotland in
the Middle Ages, a small, emergency defense
structure, generally a low, fortified tower, usable
as a dwelling place.

peeling 1 . A process in which thin flakes of
mortar are broken away from a concrete surface,

peel

as by deterioration or by adherence of surface
mortar to forms as they are removed. 2. A defect
in a paint film or plaster finish which causes the
film or finish to lose its adhesion to the sub-
strate, so that it can be removed in strips.

peel tower Same as peel.

peen, pean The end of a hammer opposite the
flat hammering face; may terminate in a cone-
shaped, rounded, or sharply pointed face.

CROSS PEEN
HAMMER

BALL-PEEN
HAMMER

peen

STRAIGHT PEEN
HAMMER

peen»coated nail See mechanically galva-
nized nail.

peening The working of a metal by means of
hammer blows.

peg l.A pointed pin of wood, metal, or any
other material; usually used as a fastener. 2. A
cylindrical piece of wood used as a dowel pin to
fasten wood members.

pegboard, perforated hardboard A hard
composition fiberboard material in sheet form,
usually about l A in. (0.6 cm) thick, having regu-
lar rows of holes in it, through which hooks or
pegs may be fastened.

711

peggies

peggies Slates of random length and width.
peggy timber Same as pecky timber.

pegma 1. Any ancient construction material
made of boards that are joined together. 2. A
machine used in a Classical Roman amphitheater
to facilitate a quick change of scenery on the stage.

peg mold A running mold.

peg stay A type of casement stay used to hold a
casement, 1 open.

pein Same as peen.

pele Same as peel.

pellet l.Any small, round, decorative projec-
tion; usually one of many. 2. A circular wood
plug which covers a countersunk screw.

pellet molding A molding decorated with a
series of small, flat disks or hemispherical projec-
tions.

i9 : 9 iff 1 flS

pellet molding

pelmet A valance or cornice, sometimes decora-
tive, built into the head of a window to conceal
the drapery track or blind brackets or fittings.

pelmet board A board, at the head of the inte-
rior side of a window, which acts as a pelmet.

pelmet lighting See valance lighting.

pen l.A synonym for room in a four-sided
enclosure constructed of logs. Thus, a one-room
log cabin is often called a single-pen cabin, and a
dogtrot cabin (consisting of two single-room
cabins) is often called a double-pen cabin. 2. An
enclosure for animals; for example, a pigpen.

penal sum The amount named in a contract or
bond as the damages or penalty to be paid by a
signatory thereto in the event he fails to perform
his contractual obligations or does not do so
within the time prescribed by the contract.

penalty-and-bonus clause See bonus-and-
penalty clause.

penalty clause A contract provision setting
forth the damages a party must pay in the event
of his breach. If such a clause is regarded by the
court as too harsh to be regarded as a fair estimate

of probable damages, it will normally be held
invalid. See liquidated damages.

penciled Descriptive of a mortar joint in a brick
wall used in the early 19th century when
extremely thin mortar joints were fashionable.
They were prepared as follows: First, the wall, with
mortar joints flush with the brick surface, was
painted the color of the brick; then a narrow white
line painted along the center of the mortar joints.

pencil rod Any rod having a diameter approxi-
mating that of a lead pencil.

pendant newel Same as newel drop.

pendant, pendent, pendent drop 1. A sus-
pended feature or hanging ornament used in the
vaults and timber roofs of Gothic architecture or
Gothic Revival; also called a pendent. 2. A

pendant, 1: A

pendant, 2 on an Early New England house

712

pendice

carved or turned wood ornament that termi-
nates the bottom end of second-floor posts in
framed overhang construction, also called a
drop or corner drop; or such an ornament on
each side of the front door. 3. An electrical
device or piece of equipment that is suspended
from overhead by means of a flexible cord carry-
ing the current.

pendant luminaire A suspended luminaire.

pendant post In a hammer-beam roof, the

lower post at the foot of the truss.

pendant sprinkler A sprinkler in a fire-
protection system designed in which the water
stream is directed downward against a deflector
disk, developing a spray pattern.

pendant switch An electric wiring switch
which is suspended from overhead at the end of
a two-conductor cord; used to control lamps or
other devices that are mounted overhead,
beyond the reach of a person standing on the
floor.

pendentives, 1: a

pendant switch

pendent Same as pendant.

pendentive 1. One of a set of curved wall sur-
faces which form a transition between a dome
(or its drum) and the supporting masonry. 2. In
medieval architecture and derivatives, one of a
set of surfaces vaulted outward from a pier, cor-
bel, or the like.

pendentive bracketing Corbeling in the
general form of a pendentive; common in Moor-
ish and Muslim architecture.

pendentive cradling The curved ribs in
arched and vaulted ceilings, used to carry or sup-
port the plasterwork.

pendent post, pendant post 1 . In a medieval
principal roof truss, a short post placed against
the wall, its lower end supported on a corbel or
capital, and its upper end carrying the tie beam or

pendentive, 2

hammer beam. 2. The support of an arch across
the angles of a square.

pendent sprinkler A fire sprinkler (i.e., sprin-
kler head) designed to be installed below the
piping in a sprinkler system; the water stream
discharged by the head is directed downward
against a deflector (a flat-toothed disk) that
develops the sprinkler spray pattern.

pendice See penthouse.

713

pendiculated

pendiculated Supported by a pendicule.

pendicule A small pillar which serves as a sup-
port.

pendill Same as pendant, 2.

pendill

pendulum saw See swing saw.

penetralia 1. The interior part of a building, as
a sanctuary. 2. An inner apartment.

penetrating finish A low-viscosity oil or var-
nish which penetrates wood, leaving a very thin
film at the surface.

penetration 1 . The intersection of two vault-
ing surfaces. 2. The consistency of a bitumi-
nous material expressed as the distance (in
hundredths of a centimeter) that a standard
needle vertically penetrates a sample of the
material under known conditions of loading,
time, and temperature. Unless otherwise speci-
fied, the load, time, and temperature are under-
stood to be 100 g, 5 sec, and 25°C (77°F),
respectively.

penetration resistance 1. The resistance by
a subsoil to penetration by pile, casing, or sam-
pling device; measured by the number of blows
of a hammer of specified weight, falling
through a specified distance to drive it a speci-
fied distance. 2. See standard penetration resis-
tance.

penetration test A test which measures the
relative density of silt or sand at the bottom of a
borehole. Also see dynamic penetration test and
static penetration test.

penetrometer A device that measures the
depth to which a standard needle penetrates a
material under standardized conditions.

peninsula-base kitchen cabinet A kitchen
cabinet which extends outward at right angles
from a row of cabinets and has one exposed end.

Penn plan Similar to the Quaker plan, but
having an interior chimney rather than an exte-
rior chimney.

Pennsylvania Dutch The German-speaking
immigrants and their descendants who settled in
Pennsylvania primarily during the 18th century.
For examples of their architecture, see bank
barn, forebay barn, German Barn, hex barn,
Pennsylvania Dutch barn, pfeiler, rauchkam-
mer, springhouse.

Pennsylvania Dutch barn, Pennsylvania
barn A two-story barn, built into the slope of
a hill, whose upper structure overhangs the story
below on the downhill side.

penny, penny-size l.A unit denoting the
length of a nail; for the common nail, and others
which have been standardized, it also is an indi-
cation of the shank and head diameter. 2. (Abbr.
d) A suffix indicating the size of a nail; the size
specifies the length of the nail and the number
of nails per pound, e.g., a 2d nail is 1 in. long and
there are 875 per pound.

pent 1. Same as chimney pent. 2. Same as pent
roof. 3. A small room, lean-to, or shed, often
with one or more open sides.

pentachlorophenol A toxic, oil-soluble
chemical; widely used as a wood preservative for
protection against decay and insects.

pentacle In Gothic tracery a five-pointed star
motif with a pentagon in the center.

pentastyle A term descriptive of a portico hav-
ing five columns in front.

penthouse, pendice, pentice 1. A structure
occupying usually less than half the roof area of
a flat-roofed building, and used: (a) to house
equipment for elevator, ventilation or air con-
ditioning, or other mechanical or electrical sys-
tems serving the building, or (b) to house one or
more apartments, access to which is gained by a
stair or stairs, or a separate elevator but usually
not by the building's main elevators. 2. An
appentice.

714

perfect diffusion

pentastyle

pentice 1. A small pent roof, 1 on a side of a
building, often restricted to the area over a door.
2. See penthouse.

pent roof 1. A small eaves-like projection from
the facade of a house between the first and sec-
ond floors; has a single straight slope; may pro-
vide very limited shelter for a window or door
directly below, but is usually merely decorative.
Frequently called a visor roof; also see skirt-roof.
2. Same as shed roof.

pepperbox A small cylindrical tower or turret
resembling the shape of a pepperbox used to
sprinkle ground pepper; often has a conical
roof.

pepperbox turret A turret circular in plan
and with some form of conical or domical roof.

peppermint test A scent test, in a plumbing sys-
tem, using oil of peppermint as the source of odor.

pepper»pot A small turret having a peaked
conical roof.

percentage agreement An agreement for
professional services in which the compensation
is based upon a percentage of the construction
cost.

percentage fee Compensation based upon a
percentage of construction cost. Also see fee.

percentage humidity The ratio of the weight
of water vapor in a pound of dry air to the weight
of water vapor that would be present if the same
weight of air were saturated; the ratio is
expressed as a percentage.

percentage reinforcement The ratio of cross-
sectional area of reinforcing steel to the effective
cross-sectional area of a member, expressed as a
percentage.

percentage rental A rent paid by a tenant to an
owner, usually comprising a minimum monthly
payment plus a specified percentage of the value
of business done by the tenant during the month.

percentage void The percentage of superficial
area which is lost by holes, perforations, or cores.

percent fines 1 . The percentage of material in
aggregate finer than a given sieve, usually the
74-|lm (No. 200) sieve. 2. The amount of fine
aggregate in a concrete mixture expressed as a
percentage, by absolute volume, of the total
amount of aggregate.

percent saturation The ratio of the volume of
water in a given soil mass to the total volume of
intergranular space, expressed as a percentage.

percent voids See percentage void.

perch A unit of cubic measure used by stone
masons; usually l6Vik by lYift by 1 ft (5.03 m
by 0.46 m by 0.30 m).

perched water table A water table (usually of
limited area) maintained above the normal free
water elevation by the presence of an interven-
ing relatively impervious confining strata.

perclose See parclose.

percolation The downward movement of
water into soil.

percolation test A test to determine the rate
at which a particular soil absorbs effluent; a hole
is dug in the soil and filled with water, then the
rate at which the water level drops is measured.
(See illustration p. 716.)

percussion drill A drill, 3, usually driven by
compressed air, in which the drilling action is
the result of a series of impacts transmitted by a
drill rod to a drill bit.

perennial A plant or shrub whose life cycle is
greater than 2 years.

PERF On drawings, abbr. for "perforate."

perfect diffusion 1. (in lighting) The condi-
tion in which light flux is uniformly scattered
in all directions so that the luminance (radi-
ance) is equal in all directions. 2. (in room
acoustics) The condition in which sound waves

715

perfect six

LAYER OF
GRAVEL

percolation test

travel in all directions with equal probability
so that the sound level of the reflected sound is
equal throughout the room.

perfect six A three-story brick house having
two families per floor and a central entrance;
often has a Classical roof cornice.

perfection A long red cedar shingle having a
butt thickness of %6 in. (1.4 cm).

perforated brick (Brit. ) A brick or block in
which holes passing through it exceed 25% of
its volume, and in which the holes are not
small (as defined under solid masonry unit, 2);
up to three holes, not exceeding 5 sq in. (32.5
sq cm) each, may be incorporated as an aid to
handling.

perforated facing In an acoustical assembly,
any flexible or rigid perforated sheet or board
designed as a protective surface allowing free
access of sound to an underlying layer of sound-
absorptive material.

perforated gypsum lath A gypsum lath
which has perforations to provide mechanical
keying of the base-coat plaster.

perforated hardboard See pegboard.

perforated metal Sheet metal usually having
a regular pattern of perforations; available in
many designs.

perforated metal pan, metal pan The

exposed finish portion of an acoustical ceiling
assembly, in which the metal pan contains and pro-
tects a separate pad or layer of sound-absorptive
material.

CHANNEL CLIPS
CHANNEL

SOUND-
ABSORPTIVE
PAD

PERFORATED

METAL PAN

BARS

perforated metal pan

irated tape A type of tape used in finish-
ing joints between gypsum boards.

perfo

perforated tape covering a joint

perforated tracery Same as net tracery.

perforated wall See pierced wall.

performance bond A bond of the contractor
in which a surety guarantees to the owner that
the work will be performed in accordance with
the contract documents; frequently combined
with the labor and material payment bond;
except where prohibited by statute.

performance curve A graphic representation
of an operating characteristic of a piece of equip-
ment, such as a fan; shows how such a character-
istic varies as a function of a single parameter
(for example, volume flow rate vs. fan speed).

716

peristalith

performance requirement A requirement
that a material, device, piece of equipment, or a
system must possess a stated characteristic.

performance specification A specification

based on the performance required of a given
assembly, component, device, equipment, or
material. Often such a specification refers to rel-
evant standards.

performance standard In building construc-
tion, a standard which defines the required per-
formance of the building (taken as a whole) or of
specified building components.

performance test A test to determine whether
or not a given assembly, material, device, piece of
equipment, or system meets its performance
requirements.

perget Same as parget.

pergola 1 . A garden structure with an open
wooden-framed roof, often latticed, supported
by regularly spaced posts or columns. The struc-
ture, often covered by climbing plants such as
vines or roses, shades a walk or passageway. 2. A
colonnade which has such a structure.

pergula Same as pergola.

periaktos In an ancient Greek theater, one of

the two pieces of machinery placed on both sides

of the stage for shifting scenes.
peribolus A sacred enclosure surrounding an

ancient Classical temple.
periclase A crystalline mineral which is some-
times found in portland cement, portland

cement clinker, and certain slags.
peridrome In an ancient peripteral temple, the

open space or passage between the walls of the

cella and the surrounding columns.

peridromos The narrow passage around the
exterior of a peripteral building behind the sur-
rounding columns.

periform Pear-shaped; said of a roof in the form of
a pear (as some baptisteries and Eastern churches)
or said of a molding having a pear shape.

perimeter beam A wood beam attached to
the edges or exposed ends of floor joists.

perimeter bracing A vertical bracing element
that is located at the perimeter of a building; also
called peripheral bracing.

perimeter drain A drain at the base of a foun-
dation wall that carries water away from it.

perimeter/floor ratio On a typical floor of a
building, the total length of a floor's perimeter
divided by the enclosed floor area.

perimeter grouting Grouting, at relatively low
pressure, around the perimeter of an area which is
subsequently grouted at a higher pressure.

perimeter heating system A warm-air heat-
ing system in which the ducts are embedded in
the concrete slab of a basementless house, around
the perimeter of the rooms; heated air from the
furnace is carried through the ducts to registers
placed in or near the floor; air is returned to the
furnace from registers near the ceiling.

FLUE
RETURN AIRrT;

ROOM PARTITION

fir

perimeter heating system

perimeter raceway Same as baseboard race-
way.

Period Revival Not a specific architectural
style, but rather a term that usually denotes a his-
toric revival of some architectural mode; for
examples, see Colonial Revival, Georgian Revival,
Mission Revival, Pueblo Revival, Spanish Colo-
nial Revival, Tudor Revival.

peripheral bracing Same as perimeter bracing.

periphery wall An exterior wall.

peripteral A term descriptive of a classical build-
ing that is surrounded by a single row of columns.

1 j 1 I

fl"

1 1 1 IJ-

myVJLHr«MJ

. ,

periptera

hav

peripteros, periptery A building having a
peristyle of a single row of columns.

peristalith A circle of upright stones surround-
ing a burial mound.

717

peristasis

peristasis The ring of columns which encircles
a peripteral building.

peristele One of the upright stones in a peristalith.

peristerium The inner or second ciborium.

peristyle 1 . A colonnade surrounding either
the exterior of a building or an open space, e.g.,
a courtyard. 2. The space so enclosed.

perithyride Same as ancon.

perling Same as purlin.

perlite A siliceous volcanic rock; under heat it
expands to 15 to 20 times its original volume,
forming an excellent lightweight aggregate; used
in plaster or gypsum wallboard, as loose-fill ther-
mal insulation, and as an aggregate in concrete.

perlite plaster Gypsum plaster which contains
perlite as an aggregate instead of sand.

perlitic Said of a material having a structure
similar to that of perlite.

perm A unit of water vapor permeance; in US
Customary units, 1 perm equals one grain of
water vapor transmitted per one square foot per
hour per inch of mercury pressure difference.

PERM On drawings, abbr. for "permanent."

permafrost Permanently frozen soil, subsoil, or
other deposits in arctic or subarctic regions.

permanence Of an adhesive bond, the bond's
resistance against deteriorating influences.

permanent bracing Bracing so designed and
installed as to form an integral part of the final
structure; may also serve as erection bracing.

permanent construction A term that usu-
ally encompasses construction at a job site other
than the following: land preparation (such as
clearing, grading, and filling); excavation for a
basement, cellar, footings, foundations, or piers;
erection of temporary forms; the installation on
the property of accessory buildings such as
garages or sheds not occupied as dwellings and
not part of the main building.

permanent form Any concrete form that
remains in place after the concrete has devel-
oped its design strength.

permanent formwork, permanent shut-
tering A type of formwork that remains in
place after the concrete work has set.

permanent load The load which is perma-
nently supported by a structure, such as the dead
load or any fixed loads.

permanent seating In a place of assembly,
seats that remain fixed in place for a specified
minimum period of time; for example, for at
least six months or more.

permanent set The change in length (ex-
pressed as a percentage of the original length) by
which an elastic material fails to return to origi-
nal length after being stressed for a standard
period of time. Also see set.

permanent shore A dead shore.

permanent shuttering Permanent formwork
which is left in place after the pouring of con-
crete so that it forms part of the structure.

permeability 1 . The property of a porous
material which permits the passage of water
vapor through it. Also see permeance. 2. The
property of soil, rock, or mantle which permits
water to flow through it.

permeability test A test to determine move-
ment through concrete of water under pressure.

permeameter An apparatus which measures the
permeability, 2 of soils and other similar materials.

permeance A measure of a material's resis-
tance to water-vapor transmission, expressed in
perms. Equal to the ratio of (a) the rate of water
vapor transmission through a material or assem-
bly between its two parallel surfaces to (b) the
vapor pressure differential between the surfaces.

permissible stress Same as allowable stress.

permissible working load The working load

that a structure is expected to sustain.

permit A document issued by a governmental
authority having jurisdiction to authorize spe-
cific work by the applicant.

PERP On drawings, abbr. for "perpendicular."

perpend, perpend stone A rectangular stone
set with its longest dimensions perpendicular to
the face of a masonry wall; extends through the
entire thickness of the wall so that it is exposed
on both faces of the wall.

Perpendicular style, Rectilinear style The
last and longest phase of Gothic architecture in
England, ca. 1350-1550, following upon the Dec-
orated style and eventually succeeded by Eliza-
bethan architecture. Characterized by vertical
emphasis in structure and frequently elaborate fan
vaults. Its final development (1485-1547) is
often referred to as Tudor architecture.

718

Persic column

perpendicular tracery, rectilinear tracery

Tracery of the Perpendicular style with repeated
perpendicular mullions often rising to the curve
of the arch, the mullions crossed at intervals by
horizontal transoms producing repeated vertical
rectangles.

perpendicular tracery

perpendiculum A plumb line, employed by
ancient masons, bricklayers, etc.

perpend wall, perpeyn wall A wall built of
perpends or of ashlar stones, all of which reach
from one side to the other.

perpeyn Same as perpend.

perron 1. A formal terrace or platform, esp. one
centered on a gate or doorway. 2. An outdoor
flight of steps, usually symmetrical, leading to a
terrace, platform, or doorway of a large building.

Persian A telamon, esp. one portrayed in Per-
sian dress.

Persic column In Egyptian Revival architec-
ture, a column having lotus ornamentation on a
bell-shaped capital.

perpend wall

perron, 2

Persia

719

persienne

persienne An exterior louver window having
adjustable slats.

person According to most codes: an individual,
partnership, corporation, or other legal entity.

persona A mask of terra-cotta, marble, etc.,
designed to imitate the human face or the head
of an animal, usually in grotesque form, em-
ployed as an antefix in buildings, as an orna-
ment for discharging water, or as a gargoyle.

persona

personal injury In insurance terminology,
injury or damage to the character or reputation
of a person, as well as bodily injury. Personal
injury insurance usually covers such situations as
false arrest, malicious prosecution, willful deten-
tion or imprisonment, libel, slander, defamation
of character, wrongful eviction, invasion of pri-
vacy, and wrongful entry. Also see bodily injury.

personal property Movables and other prop-
erty not classified as real property.

perspective 1 . The technique of representing
solid objects upon a flat surface. 2. A picture or
drawing employing this technique.

perspective center The point of origin or ter-
mination of bundles of perspective rays.

perspective drawing A graphic representa-
tion of a project or part thereof as it would
appear three-dimensionally.

OBJECT
IN SPACE

PICTURE
PLANE

PERSPECTIVE

PLANE OF
THE GROUND

PLANE OF
THE HORIZON

perspective drawing

perspective plane Any plane containing the

perspective center.
perspective projection The projection of

points by straight lines drawn through them

from some given point to an intersection with

the plane of projection.
PERT 1. Acronym for "project evaluation and

review technique." 2. See program estimation

revaluation technique.

pertica In medieval churches, a beam behind
the altar from which relics were suspended on
festival days.

PERT schedule A PERT chart of the activi-
ties and events anticipated in a work process.
Also see critical path method.

pervious cesspool See cesspool, 1.

pervious cover A vegetated area that allows
rainfall to infiltrate the soil.

pervious soil A soil which allows relatively
free movement of water.

pessulus A bolt for fastening a leaf of an
ancient Roman door. These doors, usually hav-
ing two leaves, had two (sometimes four) bolts
fixed to them — one at the top and one at the
bottom of each leaf.

petal One of the overlapping shingles or tiles in
imbrication.

pet cock, draw cock A small valve installed
in a piping system or on a piece of equipment to
drain it or to release air pockets.

720

Philippine mahogany

Petersburg standard See Petrograd standard.
Petit truss A modified form of the Pratt truss,

having subdiagonals.

petrifying liquid l.A low-viscosity pene-
trating solution of a waterproofing material for
use on masonry surfaces. 2. An additive for dis-
tempers.

Petrograd standard A British unit of timber
measure: 165 cu ft (4.67 cu m).

petrographic analysis A laboratory determi-
nation of the mineralogical and chemical char-
acter of rocks; by extension, an analysis of the
constituents of concrete, yielding the approxi-
mate cement content.

petroleum asphalt Asphalt which is refined
directly from petroleum; of two types, asphalt
base and paraffin base .

petroleum hydrocarbon Any of a number of
solvents obtained from crude petroleum; used to
lower the viscosity of oils and resins contained
in paints.

petroleum spirit See mineral spirit.

pew In a house of worship, one of a number of
fixed benches with backs; also see box pew.

pew

pfa Abbr. for British term pulverised-fuel ash.

PFD On drawings, abbr. for "preferred."
pfeiler A pillar or pier that supports the forebay

in a Pennsylvania Dutch barn.
ph Abbr. for phot.

pH A measure of the acidity or alkalinity of a
solution; numerically equal to 7.0 for a neutral
solution; the pH value increases with increas-
ing alkalinity and decreases with increasing
acidity. Also see pH value.

PH 1. On drawings, abbr. for "phase." 2. Abbr.
for Phillips head.

1PH Abbr. for "single phase."

3PH Abbr. for "three phase."

phantom line A broken line indicating an
alternative position of delineated parts of an
object, repeated detail, or the relative position of
an absent part; usually a fine line of alternating
long and short dashes.

phase One of the basic services provided by the

architect as part of the professional services
agreement between the architect and owner;
divided into the following phases: schematic
design, design development, construction docu-
ments, bidding (negotiation), and construction
contract administration.

phased application The application of built-
up roofing plies in two or more operations, usually
at least one day apart.

phased construction Construction in which
the stages of design and construction overlap,
thereby shortening the time necessary to com-
plete the project.

phenol A class of acid organic compounds used
in the manufacture of epoxy resins, phenol-
formaldehyde resins, plasticizers, plastics, and
wood preservatives.

phenol-formaldehyde resin, phenolic re-
sin A thermosetting, waterproof, low-cost,
mold-resistant, high-strength synthetic resin
made from phenol and formaldehyde; has good
resistance to aging; used extensively in the man-
ufacture of adhesives, exterior and marine ply-
wood, laminated products, and molded articles.

phenolic foam A thermosetting foam plastic
used to provide thermal insulation.

phenolic resin See phenol-formaldehyde resin.

Philadelphia leveling rod A two-piece lev-
eling rod, with graduation marks so styled that it
may be used as a self-reading leveling rod.

Philippine ebony See ebony.

Philippine mahogany, red lauan, white
lauan The wood of trees of several genera
found in the Philippines; not a true mahogany,
but resembles true mahogany in grain; density
ranges from very light to quite heavy; whitish-
yellow to pink, brown, or dark red in color; the
heavier, darker woods are generally durable and

721

Phillips head

quite strong and are used like true mahogany;
the lighter-weight, colored woods are used for
interior carpentry, plywood, and general con-
struction.
Phillips head A screw having a special head
with crossed slots which are perpendicular to each
other.

PHILLIPS HEAD
DRIVER

Phillips head shown with a Phillips head driver

phon A unit of loudness level.

phosphated metal A metal surface which has
been pretreated with hot phosphoric acid, to
prepare it for receiving a finished coating.

phosphor A substance capable of luminescence,
such as a fluorescent powder which absorbs ultra-
violet power and reemits it as visible light; used to
coat the inside of various electric-discharge lamps.

phosphorescence The emission of light as
the result of the absorption of electromagnetic
radiation; continues for a noticeable length of
time after excitation.

phosphorescent paint See luminous paint.

phosphor mercury-vapor lamp A high-
pressure mercury-vapor lamp consisting of an
arc tube enclosed by a phosphor-coated glass
envelope; the phosphor generates colors not
produced by the arc.

phot A unit of illumination equal to 1 lumen
per square centimeter. Abbr. ph.

photisterium Same as baptistery.

photoelectric cell A device incorporated in
an electric circuit; in response to light that falls
on the cell, the electrical output or the resis-
tance varies; used in measuring devices and in
control devices that depend on illumination
level or the interruption of a light beam.

photoelectric control A control function
which is actuated by a change in incident light.

photoelectric smoke detector A sensor used
to initiate a fire alarm when smoke reduces the
light received by a photoelectric cell in a device
containing a light source; most effective in the
early detection of fires in the smoldering stage.

photogrammetry The technology of obtain-
ing reliable distance measurements by photo-
graph.

photographing Same as telegraphing.

photometer Any instrument that measures
photometric quantities such as luminance, lumi-
nous intensity, luminous flux, and illumination.

photometry The measurement of quantities
associated with light.

photo sensor See photoelectric cell.
Phrygian marble Same as pavonazzo, 2.

phthalocyanine pigments Exceptionally du-
rable, permanent green and blue pigments used
in paints, enamels, and plastics.

pH value A number denoting the degree of
acidity or of basicity (alkalinity); 7 is a neutral
value; acidity increases with decreasing values
below 7; basicity increases with increasing val-
ues above 7.

physical depreciation That depreciation in
value of a building that results from aging, usage,
and wear and tear.

physical disability, physical handicap

Legally, any of the following handicaps: an
impairment requiring the use of a wheelchair; an
impairment causing difficulty or insecurity in
walking or climbing stairs or requiring the use of
braces, crutches, or other artificial supports;
impairment (partial or total) of hearing or sight,
causing likelihood of exposure to danger in pub-
lic places; or impairment due to conditions of
aging or incoordination. Also see Americans
with Disabilities Act.

physical stability The ability of a product to
maintain its physical dimensions and properties
when exposed to conditions normally encoun-
tered in its service environment.

piache A covered arched walk, or portico.

piano hinge See continuous hinge.

piano nobile In Renaissance architecture and
derivatives, a floor with formal reception and
dining rooms; the principal story in a house, usu-
ally one flight above the ground.

722

piece sur piece construction

piazza l.A public open space or square sur-
rounded by buildings. 2. A term occasionally
used for a raised porch or veranda in French
Vernacular architecture or in American Colo-
nial architecture and derivatives (especially in
the South); often supported by columns or
posts.

piazza house A term occasionally used for a
Charleston house.

pick A hand tool used for loosening and break-
ing up closely compacted soil and rock; consists
of a steel head which usually is curved, with a
point on one or both ends, mounted on a
wooden handle.

pick and dip, Eastern method, New
England method A method of laying
brick whereby the bricklayer simultaneously
picks up a brick with one hand and, with the
other hand, enough mortar on a trowel to lay
the brick.

pickax A pick or mattock.

pick dressing The first rough dressing of hard
quarried stone by use of a heavy pick or wedge-
shaped hammer.

picked finish In stone masonry, a surface fin-
ish covered with small pits produced by a pick or
chisel point striking the face perpendicularly.

picket Same as pale, 1.

picket fence A fence formed of a series of ver-
tical pales, posts, stakes, rods, etc. (sometimes
sharpened at the upper end) which are joined
together by horizontal rails.

picking, stugging, wasting Same as dab-
bing.

picking up The blending of a coat of freshly
applied paint with another over which it is
applied. Also see pulling up.

pickled Said of a metal surface which has
been treated with a strong oxidizing agent,
such as nitric acid, to clean, to provide a strong
inert oxide film, and to increase corrosion
resistance.

pick point A location on the ceiling of an
auditorium from which a banner, microphone,
scenic element, or the like may be supported and
lowered as required.

pickup The unwanted adherence of solids in
contact with the open surface of a sealant.

pickup load The abnormal rate of heat con-
sumption that takes place when a heating system
is first turned on; represents the heat dissipated
in bringing the piping and radiators to their nor-
mal operating temperature.

picnostyle, pycnostyle See intercolumnia-
tion.

picowatt (pW) A unit of power equal to a mil-
lionth of one-millionth of a watt (i.e., 10~ 12 W).

picture molding, picture rail Any of
numerous types of moldings or other such
devices formed so as to support picture hooks at
or near the ceiling.

picture plane In perspective drawing, a plane
upon which can be projected a system of lines or
rays from an object to form an image or picture.

Picturesque Gothic A term sometimes
applied to High Victorian Gothic architecture.

Picturesque Movement A movement estab-
lished by a group of architects from about 1 840
to 1900, particularly in Europe, wedded to the
concept that architectural ideals should look
away from formal Classical architecture and
instead should embrace the romanticized past.
The term "Picturesque" is not indicative of a
particular architectural style, but is suggestive of
a number of styles or modes of architecture that
were related to the romanticized past, including:
Exotic Revival, Gothic Revival, Italianate style,
Queen Anne style, Richardsonian Romanesque
style, Second Empire style, Stick style, Swiss
Cottage architecture.

picture window In a home or apartment, a
large, fixed window, often between two narrower
operable windows; usually located so as to
present the most attractive view of the exterior.

piece dyeing The dyeing of fabric after it has
been woven, in contrast to dyeing the yarn prior
to weaving.

pieced timber 1 . A timber made from two or
more pieces of wood fitted together. 2. A dam-
aged timber repaired with a fitted piece of wood.

piece mark A mark placed on an individual
piece of an assembly, designating its location in
the assembly as indicated in shop drawings.

piece sur piece construction In the
French Vernacular architecture of Louisiana,
primarily in the 18th century, a method of
building small houses of well-finished, heavy

723

pien

rectangular-hewn timbers. Each timber, laid
horizontally, had a dovetail notch at both ends,
forming a strong interlocking rigid joint with
another appropriately notched timber at right
angles to it.

pien, piend 1. The ridge of a roof. 2. An arris; a
salient angle.

pien check, piend check In a stair con-
structed with hanging steps of stone, a rabbet cut
along the lower front edge of a step which fits
into the back of the step next below it.

piend rafter Same as hip rafter.

pien joint In a stone stair, the joint between
two steps which are secured by a pein check.

pier l.A column designed to support concen-
trated load. 2. A member, usually in the form of
a thickened section, which forms an integral
part of a wall; usually placed at intervals along
the wall to provide lateral support or to take
concentrated vertical loads.

PIER FORM

FOOTING FORM

typical concrete form for a pier, 1 and its footing

pier-and-spandrel Descriptive of a wall con-
struction having the vertical metal columns
which project beyond the plane of the windows
and the spandrels.

pier arch An arch resting on piers, esp. one
along a nave arcade.

pier block See double corner block.

pier bonding A method of bonding piers to
walls by bond bricks or stones.

pier arch

pier buttress A pier, 1 which receives the

thrust of a flying buttress.
pierced louver, punched louver A louver

that is formed in the face sheets or panels of a door.
pierced wall, perforated wall, screen

■wall A nonbearing masonry wall in which

724

pilaster block

an ornamental pierced effect is achieved by
alternating rectangular or shaped blocks with
open spaces.
pierced work Ornamentation characterized
by patterns formed by perforations; also see gin-
gerbread and openwork.

pierced work

pier glass A tall, narrow mirror, often running
from floor to ceiling, which covers the whole or
a large part of the wall between two windows.

pierrotage In French Vernacular architecture
of the southern United States, lime mortar or
clay mixed with small stones; used as infilling
between half-timbering with diagonal braces
(columbage); also see bousillage.

pietra dura A thin slab of inlaid stone used for
ornamental purposes.

pieux a travers In the French Vernacular
architecture of Louisiana, primarily in the 18th
century, upright cypress stakes, driven into the
ground in front of a house; similar in appearance
to a picket fence.

piezometer A device for measuring liquid pres-
sure; used to measure the pore water pressure in
soil.

pigeonhole 1 . One of a series of small com-
partments. 2. A seat in the top row of a gallery or
in the uppermost gallery in a theater.

pigeonhole corner An acute angle formed in
a brick wall, using square-ended bricks that have
not been shaped.

pigeonholed wall Same as honeycomb wall.

pigeonnier, pigeon house Same as dovecote.

pigeon roof A roof having four steeply sloping
sides that meet in a point, occasionally with a
decorative element atop it; also called a pyramid
roof.

pig iron Crude high-carbon iron ore that has

been smelted and cast into ingots; may be
remelted and used as a source of material for
architectural cast-iron products, or may be further
refined for use in producing steel.

pigment l.A finely ground inorganic or
organic powder which is dispersed in a liquid
vehicle to make paint; may provide, in addition
to color, many of the essential properties of a
paint — opacity, hardness, durability, and corro-
sion resistance. 2. Coloring matter, usually in
the form of an insoluble fine powder, used to
color concrete, etc.

pigment figure A pattern in wood consisting
of variations in color rather than variations in
grain; found in such woods as rosewood and
zebrawood.

pigment-to-binder ratio The ratio of the
weight of pigment to the weight of binder in a
paint, e.g., the number of pounds of pigment per
100 lb of binder.

pigment volume concentration See PVC, 1.

pigtail A flexible conductor which is attached
to an electric component, providing a means of
connecting the component to a circuit.

pigtail splice A type of connection made
between two electric conductors; formed by
placing the ends of the conductors side by side
and then twisting the ends of the two conduc-
tors around one another.

pig tin A metal which is at least 99.80% pure tin.

pila l.In churches in Italy, a holy-water font,
consisting of a bowl mounted on a shaft, as dis-
tinguished from a font hanging from or secured
to a wall or pier. 2. A square block or epistyle,
just over the columns, to support a rooftimber.
3. A mortar which is valuable or curious on
account of its antiquity or design.

pilaster 1. An engaged pier or pillar, often with
capital and base. 2. Decorative features that imi-
tate engaged piers but are not supporting struc-
tures, as a rectangular or semicircular member
used as a simulated pillar in entrances and other
door openings and fireplace mantels; often con-
tains a base, shaft, and capital; may be con-
structed as a projection of the wall itself. (See
illustration p. 726.)

pilaster base Same as base block.

pilaster block See double corner block.

725

pilaster buttress

pilasters

pilaster buttress A pilaster that diminishes
gradually in width with increasing height.

pilastered chimney A chimney shaft having
pilasters on its faces to provide a decorative
effect and/or to enhance its structural strength.

pilastered chimney

pilaster face The form for the front surface of a

pilaster, parallel to the wall.
pilaster mass An engaged pier built up with

the wall, usually without the capital and base of

a pilaster.

pilaster side The form for the side surface of a
pilaster, perpendicular to the wall.

pilaster strip, lesene Same as pilaster mass

but usually applied to slender piers of slight

projection; in medieval architecture and deriv-
atives, often joining an arched corbel table.

pilastrade A row of pilasters.

pilastrelli A small pilaster flanking a window or
door.

pile 1. A concrete, steel, or wood column, usually
less than 2 ft (0.6 m) in diameter, which is driven
or otherwise introduced into the soil, usually to
carry a vertical load or to provide lateral support.
2. See carpet pile. 3. A term used to indicate the
number of rooms in a house from front to rear; for
example, a double-pile house has two rooms
between the facade and the rear wall of the house.

pile bearing capacity The load on a pile, or
the load per pile, on a group of piles, required to
produce a condition of failure.

pile bent Piles which are driven in a row which
is transverse to the long dimensions of a struc-
ture and which are fastened together by a pile
cap and sometimes bracing.

pile butt The head of a pile.

pile cap l.A slab or connecting beam which
covers the heads of a group of piles, tying them
together so that the structural load is distributed
and they act as a single unit. 2. A metal cap
which is placed, as temporary protection, over
the head of a precast pile while it is being driven
into the ground.

pile core Same as mandrel, 1.

pile cushion A device placed between the
drive cap and the top end of a concrete pile as
protection against crushing and spalling.

pile driver A machine for delivering repeated
blows to the top of a pile for driving it into the
ground; consists of a frame which supports and
guides a hammer weight, together with a mech-
anism for raising and dropping the hammer or
for driving the hammer by air or steam. Also see
sonic pile driver.

pile driving cap See drive cap.

pile eccentricity The deviation of a pile from
its plan location, or the out-of-plumbness of a
pile; reduces the vertical load capacity.

pile encasement A protective covering on a pile.

pile extractor A machine for pulling piles
from the ground, e.g., by means of a double-act-
ing pile hammer attached to a pile, each blow of
which produces an upward force on the pile.

726

piloti (pi pilotis)

pile foot The lower end of a pile.

pile forte In sexpartite vaulting, the alternation
between massive and slender piers.

pile foundation A system of piles, pile caps,
and straps (if required) that transfers the struc-
tural load to the bearing stratum into which the
piles are driven.

pile friction The sum of friction forces acting
on an embedded pile; is limited by (a) the adhe-
sion between the pile and the soil and/or (b) the
shear strength of the soil adjacent to the pile.

pile hammer Equipment employing a weight
(hammer) which strikes a pile or beam, forcing it
into the ground; the weight may fall freely,
under the action of gravity, or be powered by
steam, compressed air, or a diesel engine.

pile head The upper end of a pile.

pile height See carpet pile height.

pile helmet Same as pile cap, 2.

pile hoop Same as drive band.

pile load test A test in which a load (usually
150% or 200% of the design load) is applied on
a pile to verify or aid in the selection of a design
load.

pile penetration The depth which is reached
by the tip of a pile.

pile rig Same as pile driver.

pile ring Same as drive band.

pile shoe A pointed or rounded metal device
on a pile foot to aid in pile driving.

pile tolerance 1 . The permitted deviation of a
pile from the vertical. 2. The permitted devia-
tion in the horizontal plane.

pile tower Same as peel.

pile weight See carpet face weight.

pilier In French Vernacular architecture of
Louisiana, a stack of rectangular blocks of (rot-
resistant) cypress wood used to support a Creole
house, transferring the structural load from the
groundsill to the earth below.

pilier cantonne High Gothic form of the com-
pound pier, with a massive central core to which
are attached at 90° intervals four colonettes sup-
porting the arcade, the aisle vaultings, and the
responds of the nave vaults.

piling The property of a paint which causes it to
gain viscosity rapidly during application, making
it difficult to apply a smooth uniform film.

piling pipe A seamless pipe or welded pipe,
having beveled ends for welding or plain ends,
where the cylinder section acts as a shell to form
cast-in-place concrete piles or as a permanent
load-carrying member.

pillar A column, pier, pilaster, or post that is
capable of providing major vertical support.

pillar: Perpendicular style

pillar bolt A stud bolt which projects; used for
supporting a part near its outer end.

pillar piscina A free-standing piscina resting
on a pillar.

pillar»stone 1. Same as cornerstone. 2. A stone
memorial, usually pillar-shaped.

pillow capital See cushion capital.

pillowed See pulvinated.

pillowwork The decorative treatment of any
surface with pillow-like projections.

pilot boring In foundation construction, a pre-
liminary boring or series of borings used to deter-
mine boring requirements.

pilot hole A hole which serves as a guide for a
nail or screw, or for drilling a larger-size hole.

piloti {pi. pilotis) One of a number of isolated
columns, posts, or piles that support a building,
raising it above ground level; the ground floor is
open to the exterior.

727

pilot lamp

pilot lamp Same as pilot light, 1.

pilot light 1 . A light which is associated with and
indicative of the operation of a circuit, control, or
device. 2. A small flame (which burns constantly)
used to ignite the burner in a gas appliance.

pilot nail A temporary nail which is used to
hold boards or timbers together until the perma-
nent nails are driven in.

pilot punch A machine punch in which the
cutting tool is provided with a small central plug
which fits into a hole in the material and acts as
a guide for punching a larger hole.

pilot valve An automatic valve that regulates
the air pressure in a compressor.

pin 1. A peg or bolt of wood, metal, or any other
material, which is used to fasten or hold some-
thing in place, fasten things together, or serve as
a point of attachment or support. 2. A round bar
of steel used to connect members of a truss.

pinacotheca A picture gallery.

pinaculum In ancient Greek or Roman archi-
tecture, a roof terminating in a ridge (the ordi-
nary covering for a temple; in contrast, private
houses had flat roofs).

pinax A decorative panel which fills the inter-
columniations of the proskenion or the thyro-
mata (pi. of thyroma) at the back of the stage of
an ancient Greek or Roman theater.

pincers A tool having two hinged jaws which

can be closed tightly; used for gripping objects.
pinch bar, claw bar, ripping bar, wrecking

bar A steel bar with a U-shaped claw at one
end and a chisel point at the other; often used as
a lever for lifting heavy objects.

pin-connected truss Any truss having its
main members joined by pins.

pin drill A drill for boring pin holes, 5 in truss

members.

pine The wood of a number of species of conif-
erous evergreen distributed throughout the
world; may be divided into two classes: soft
(white) pine and hard (pitch) pine. An impor-
tant source of construction lumber and ply-
wood.

pineapple 1. An ovoid, imbricated finial. 2. A
decorative molding.

pineapple ornament A decoration, usually
carved in wood or cast in plaster, that resembles

pineapple, 2

the cone of a pine tree; often found as a pendent
or finial.

pine oil A strong, high-boiling-point solvent
obtained from the resin of pine trees; used in paint
to provide good flow properties in application.

pine shingles Shingles of pine wood; much
used in Europe and, at one time, in the US

pine tar A viscous black substance, used in roof-
ing, which is manufactured by distilling pine wood.

pin hinge A hinge having a pin on which the
hinge pivots; also see loose-pin hinge.

pinhole 1. In wood, a round hole usually less
than V* in. (0.6 cm) in diameter, caused by the
boring of a beetle or worm in standing timber.

2. In a plaster coat, a surface defect resulting from
trapped air bubbles. 3. In a paint film, one of
many small holes caused by: (a) impurities (in the
paint, on the paintbrushes or rollers, or on the
surface being painted); (b) solvent bubbling; or
(c) moisture. 4. In the surface of a ceramic body,
glaze, or porcelain enamel, an imperfection char-
acterized by a depression resembling a pinprick.
5. A hole in a structural member through which a
pin, 2 passes and connects with another member.

pin joint A joint in which one member is fas-
tened to another by a pin so that rotational move-
ment at the point of joining is not restricted.

pin knot 1 . ( US ) A knot in wood that is no larger
than Vi in. (1.27 cm) in diameter. 2. (Brit.) A knot
in wood less than Vi in. (0.64 cm) in diameter.

pinnacle 1. An apex. 2. In Gothic architecture
and derivatives, a small, largely ornamental
body or shaft terminated by a pyramid or spire.

3. A turret, or part of a building elevated above
the main building.

pinned joint A joint that is secured by the use
of wood dowels rather than by wedges.

pinner In masonry construction, a small stone
which supports a larger one.

728

pipe cutter

pinnacle, 2: St. Mary's,
Oxford

pipe bend A pipe fitting, 1 used to achieve a

change in direction.
pipe bracket Any of a variety of shaped metal

assemblies used to support a pipe from a wall or

floor.
pipe chase See chase.
pipe column A column made of steel pipe;

may be filled with concrete.
pipe coupling A coupling.
pipe covering A wrapping around a pipe which

acts as thermal insulation and/or a vapor barrier.
pipe cross A pipe fitting, 1 having four open-
ings in the same place, at right angles to each

other.

pipe cross

pinning 1. Fastening or securing with a pin. 2.
A foundation or underpinning.

pinning in The operation of filling in the joints
of masonry with spalls or chips of stone.

pinning up The operation of driving in wedges
in order to bring an upper work fully to bear on
shoring or underpinning beneath.

pinrail See fly rail.

pin spotlight A small spotlight, focused in a rel-
atively narrow beam, used to highlight an object
of interest; for example, it may be mounted in the
ceiling to illuminate a picture on a wall.

pintle A pin on which something is hung and
about which it revolves; esp. one that projects
upward.

pintle hinge A hinge that pivots about an
upright pin or bolt.

pin tumbler A lock mechanism having a series
of small cylindrical pins which form obstacles to
rotation of the locking mechanism unless actu-
ated by the proper key.

pipe A continuous tubular conduit, generally
leakproof, for the transport of liquids and gases.

pipe batten A batten, 9 used to hang scenery
from stage rigging in a theater.

pipe cutter A hand tool for cutting pipe or
tubing; one end of the tool, which partially
encircles the pipe, carries one or more sharp
wheels; the cutting edge of the wheels is forced
against the pipe by a screw on the other end of
the tool; cutting is effected by rotating the tool
around the pipe.

CUTTING WHEEL

pipe cutter cutting pipe

729

pipe die

pipe die Any of several types of adjustable tools
for cutting threads on pipes used in plumbing.

pipe duct A duct in which only pipes are run.

pipe elbow See elbow, 1.

pipe exfiltration See exfiltration, 2.

pipe expansion joint A device, other than a
fabricated U-bend, which expands or contracts
to compensate for pipe contraction or expansion.

pipe fitting See fitting, 1.

pipe gasket A gasket, 2 in a piping system.

pipe hanger A device to support a pipe or
group of pipes from a slab, beam, ceiling, or
other structural element.

Anchor

Rod coupling
Hanger rod

Pipe hanger

Pipe

pipe hanger

pipe heating cable See strip heater.

pipe hook A device for supporting a pipe from

a wall.
pipe infiltration See infiltration.

pipe insulation Thermal insulation (such as
fiberglass or foamed plastic) usually manufac-
tured in hemicylindrical shapes for pipes of vari-
ous diameters.

45° pipe lateral A pipe fitting similar to a pipe
tee except that the side opening is at a 45° angle.

pipelayer An attachment for a tractor or other
prime mover that consists of a winch and a side
boom for lowering sections of pipe into a
trench.

pipeline heater A heater for a pipeline, usu-
ally wrapped around the piping and heated by
an electric current; used to prevent the liquid
in the piping from freezing or, changing its vis-
cosity.

pipeline refrigeration Refrigeration provided
by piping a refrigerant to a group of buildings
from a central refrigerating plant.

pipe pile 1. A pipe section heavy enough to be
driven without a mandrel, 1 having its lower end
either open or closed; after the pipe is driven to
its final position, it is filled with concrete. 2. A
pipe (either close-ended or open-ended) which
serves as a pile.

pipe plug A threaded pipe fitting with male
threads; used to close the end of a ferrule or a
pipe having female threads.

pipe plug

pipe reducer For a pipe, see reducer.

pipe ring Any of a variety of circularly shaped
metal assemblies used to support a pipe loosely
from a suspended rod.

pipe run The path taken by piping.

pipe saddle A vertical support on which a pipe
rests.

pipe schedule (sprinkler) system A fire
sprinkler system in which the sizing of the
pipes supplying the sprinklers is determined
from a schedule based on occupancy classifica-
tion; a specified number of sprinkler (heads)
may be supplied for a specific size of pipe.

730

pishtaq

Pipe

Pitch of the thread

[filler -

Saddle

/7777777777777777T7

pipe saddle

pipe sleeve 1. A cylindrical insert, placed in a
form for a concrete wall, in a location where a
pipe is to pierce the wall; the insert prevents
concrete from flowing into the cylindrical open-
ing. 2. A pipe coupling.

pipe sleeve, 1

pipe stock A device to hold a pipe die.

pipe stop A spigot in a pipe.

pipe strap A thin metal strip used to hang pipe.

pipe support A mount for supporting a large
pipe; often on a saddle, 3. A support of this type
may include a roller to permit movement of the
pipe caused by its expansion and contraction.

pipe tee A T-shaped pipe fitting with two outlets,
one at 90° to the connection to the main line.

pipe thread A V-cut screw thread, cut on the
inside or the outside of a pipe (or on a pipe fit-
ting, coupling, or connector); the diameter of
the thread is not constant, but tapers.

pipe tongs A tool used by plumbers or pipe fitters
to screw or unscrew lengths of pipe or pipe fittings.

pipe trim The exposed metal appurtenances of
plumbing fixtures, such as faucets, spigots, and
exposed traps.

rn perfect threads

Effective
tapered pipe thread

pipe underlayment The base on which a pipe
is laid in the ground in order to achieve a firm,
even bearing.

pipe vise A vise for holding pipe or tubing dur-
ing cutting or threading operations; the pipe is
held either in V-shaped serrated jaws or (for
larger pipe) by chains.

pipe wrench A hand tool having one jaw
movable and the other relatively fixed, the two
being shaped so as to tighten when placed on a
pipe and rotated in one direction.

pipe wrench

piping 1 . The movement of soil particles by water
which percolates through the soil, leading to the
development of erosion channels. 2. A run of pipe.

piping loss The loss of heat from piping
between the source of heat and radiators.

pirca A type of crude wall construction using
dry-laid unshaped stones, found in the Andes.

pisay Same as pise.

piscina A shallow basin or sink, supplied with a
drain pipe, generally recessed in a niche. (See
illustration p. 732.)

pise 1. Same as rammed earth. 2. A mixture of
clay and chopped straw, sometimes with the
addition of gravel; particularly used in wall con-
struction. 3. Cob used as a wall material.

pishtaq In Muslim or Persian architecture, a
monumental gateway marking the entrance to a
mosque, caravanserai, madrasah, or mausoleum.

731

pit

piscina

pit 1. An orchestra pit. 2. A small circular hole in
a paint film; also see pockmarking. 3. An excava-
tion; a hole in the ground.

pit boards Horizontal boards used as sheeting
to retain earth around a pit.

pitch 1. The slope of a roof, usually expressed as
a ratio of vertical rise to horizontal run, or in
inches (centimeters) of rise per foot (meter) of
run. 2. See grade. 3. The slope of a stair flight,
i.e., the ratio of the rise to the run of the flight.
4. The distance between centers of bolts, rivets,
and other fasteners in the same line. 5. See car-
pet pitch. 6. In acoustics, that attribute of audi-
tory sensation in which sounds may be ordered
on a scale from low to high; depends primarily
on the frequency of the sound stimulus. 7. Any
of various resins. 8. A dark, viscous, distillate of
tar; used in caulking and paving; also called
pitch mastic. Also see coal tar pitch. 9. In
masonry, to square a stone with a chisel.

pitch board, gauge board A template, usu-
ally a right triangle in shape; used as a pattern to
lay out the outline of stairs or the like; in stair
construction, the base of the triangle is the exact
width of the treads of the steps, and the perpen-
dicular is the height of the riser.

pitch dimension Of stairs, the distance
between the bases of the top and bottom risers in
a flight, measured parallel to the slope.

pitched roof 1 . A steep gable roof having the
same pitch on each side of a central ridge. 2.
Occasionally, a synonym for a gable roof.

pitched-roof dormer A dormer having a tri-
angularly shaped gable.

pitched skylight A skylight whose members
are inclined.

pitched skylight

pitched stone A rough-faced stone having
each edge of the exposed face pitched at a slight
bevel, nearly in the plane of the face.

pitcher house A wine cellar.

pitch»faced In masonry, having all arrises cut
true and in the same plane, but with the face
beyond the arris edges left comparatively rough,
being simply dressed with a pitching chisel.

glys.fr <jr^y^ .-'^i

mminimmijlL,,,..,,

pitch-faced masonry

732

place brick

pitch fiber pipe Same as bituminized fiber pipe.

pitchhole A recess or depression occurring in
the surface of a stone which has otherwise been
more or less dressed to a true face for setting.

pitching chisel, pitching tool A mason's
chisel having a wide, thick edge; used in rough
dressing.

pitching piece See apron piece.

pitching tool See pitching chisel.

pitch knot A knot associated with a local area
of pitch or resin; usually found in softwoods.

pitch mastic See pitch, 8.

pitch pine Same as yellow pine.

pitch pocket 1. A defect in softwoods; consists
of an opening in the grain that contains pitch or
resin. Also called a resin pocket. 2. A metal
flange around the base of any roof-penetrating
member (or component) which is filled with
pitch or flashing cement to provide a seal.

pitch streak, resin streak A local accumula-
tion or streak of highly resinous wood in softwoods.

pith The soft central core of a log.

pith

pith fleck A short dark streak in wood resembling
pith, but caused by insect attack during growth.

pith knot A knot with a small pith hole in the
center.

pith ray See medullary ray.

pitot tube A device, used in conjunction with a
suitable manometer or other pressure-reading
instrument, for measuring the velocity of air in a
duct or water in a pipe.

pit-run gravel, bank-run gravel Un-
graded gravel as it is taken directly from a
gravel pit.

direction of am flow

pitot tube

pit sawing An old method of handsawing timber
lengthwise; the log is supported over a pit to pro-
vide easy access by men using a double-ended saw.

pitting 1 . The development of small cavities in
a surface, owing to phenomena such as corro-
sion, cavitation, or (as in concrete) localized dis-
integration. 2. In plastering, see popping. 3. The
development of localized surface defects on a
metal surface, e.g., small depressions, usually
caused by electrochemical corrosion. 4. The
localized corrosion in the form of cavities which
takes place on the surface of a metal.

pivot l.A hinge. 2. The axle or pin about
which a window or door rotates.

pivoted door A door hung on pivots (either
center pivots or offset), as distinguished from
one hung on hinges or on a sliding mechanism.

pivoted window A window having a sash
(ventilator) which rotates about fixed vertical or
horizontal pivots, located at or toward the cen-
ter, in contrast to one hung on hinges along an
edge. Also see vertically pivoted window.

pivot window A window that turns about
hinges usually aligned along a vertical axis.

pixis, pix A shrine to contain the host or con-
secrated wafer. (See illustration p . 734.)

PL l.On drawings, abbr. for pile. 2. On draw-
ings, abbr. for plate. 3. On drawings, abbr. for
plug. 4. On drawings, abbr. for "power line." 5.
Abbr. for "pipe line."

placage An ornamental thin masonry facing
(revetment) of a building.

placard Same as pargeting.

placeability See workability, 1.

place brick A poor quality brick that lacks
weather resistance; same as salmon brick.

733

placement

/'■ ■•:.■•.:■■ ■/•'; : ;:it-y^

pixis and image bracket

placement The placing and consolidation, 1 of

concrete.

place of assembly 1. A building (excluding
dwelling units), or portion thereof, in which a
specified number (the actual number depends
on the local code) of persons may gather for
recreational, educational, political, social, or
other purposes, such as to await transportation,
or to eat or drink. 2. An outdoor space where a
number of persons in excess of a specified min-
imum may gather for any of the above pur-
poses.

placing l.The deposition and compaction of
freshly mixed mortar or concrete in the place
where it is to harden. 2. The process of applying
plastic terrazzo mix to the prepared surface.

placita A central enclosed courtyard in Spanish
Colonial ranches in the Americas, surrounded
by a high adobe wall; usually entered through a
massive gate.

plafond A ceiling, esp. one of decorative char-
acter; flat or arched.

plain ashlar Stone facing that has been
smoothed with a tool.

plain bar A reinforcing bar without surface
deformations, or one having deformations that
do not conform to the applicable requirements.

plain concrete, unreinforced concrete 1.
Concrete without reinforcement or reinforced
only for shrinkage or temperature changes. 2.
Concrete without some other specific admixture
or element, in contrast with concrete containing
such an admixture or element, e.g., non-air-
entrained concrete.

plain»cut joint In masonry, same as rough-cut
joint.

plain lap Same as lap joint, 2.

plain masonry Masonry without reinforce-
ment, or reinforced only for shrinkage or tem-
perature change.

plain rail In a double -hung window, a meeting
rail having the same thickness as other members
of the frame of the sash.

plain reinforcement In reinforced concrete,
any reinforcement, 1 other than deformed rein-
forcement.

plain-sawn, bastard-sawn, flat-grained,
flat-sawn, slash-sawn Descriptive of wood
sawn so that the annual rings intersect the wide
face at an angle of less than 45°.

plain-sawn

plain slicing Same as wood veneer, 1 that is
sliced from a log without regard to the direction
of the grain.

Plains cottage, Plains house Typically, a rela-
tively simple single-family, single-story house,
constructed primarily of sod, having two to five
rooms; primarily built in the 19th century in those
parts of the Great Plains where sod was usually the
only construction material conveniently obtain-
able; also see sod house and straw bale house.

plain tile A flat rectangular roofing tile of con-
crete or burnt clay; each tile has two projecting
nibs for hanging the tile from battens.

plaisance Same as pleasance.

plan 1 . A two-dimensional graphic representa-
tion of the design, horizontal dimensions of a
building, and location, as seen in a horizontal
plane viewed from above, in contrast to a graphi-
cal representation representing a vertical plane
(such as a section, 2 or an elevation, 1). See
center-hall plan, city plan, cruciform plan, com-
munity plan, floor plan, four-square plan, gable-
front-and-wing plan, gable-front plan, Georgian
plan, ground plan, hall-and-parlor plan, hall-
house plan, H-plan, linear plan, L-plan, one-room

734

plane table

plan

plan, open plan, Penn plan, Quaker plan,
reflected ceiling plan, side-hall plan, single-room
plan, three-room plan, T-plan, two-room plan, U-
plan. 2. When used in the plural, a set of draw-
ings, including elevations and sections, that
collectively define a building. 3. See city plan and
town plan.

planar frame A structural frame composed of
individual members all of which are in the same
plane.

planch (Brit. ) 1 . A floorboard. 2. A plank floor.

planching Same as flooring.

plancier, planceer, plancer, plancher 1.

The soffit or underside of any projecting mem-
ber, as a cornice. 2. A planch.

plancier piece A board which forms a
plancier.

plan deposit See deposit for bidding docu-
ments.

plane l.A tool for smoothing wood surfaces;
consists of a smooth soleplate, from the under-
side of which projects slightly the cutting edge
of an inclined blade; there is an aperture in
front of the blade for the shavings to escape. 2.
A surface, any section through which by a like

plancier

BLADE OR PLANE IRON
LEVER CAP

plane, 1

surface is a straight line. 3. Of a column, the

surface of a longitudinal section through the

axis of the column.
plane ashlar A stone block having tool marks

on its surfaces.
planed lumber Same as dressed lumber.

planed matchboards See dressed and matched
boards.

plane of 'weakness Of a structure under stress,
that plane along which fracture is most likely to
take place, as a result of design or accident or the
properties of the structure and its loading.

plane surveying A branch of the art of survey-
ing in which the surface of the earth is considered
a plane surface; curvature of the earth is neglected,
and computations are made using the formulas of
plane geometry and plane trigonometry.

plane table In surveying, a device for plotting
the lines of a survey directly from the observations;

735

plane tile

consists essentially of a drawing board on a tripod,
with a ruler, the ruler being pointed at the
observed object by the use of a telescope or other
sighting device.

plane tile See ridge tile.

planimeter A mechanical integrator for mea-
suring the area of a plane surface usually within
a given perimeter on a map.

planing A process for smoothing the surface of
a material by shaving off small fragments.

planing machine 1. A stationary machine for
planing wood. 2. A portable machine for plan-
ing the surface of a wood floor.

planing skip See skip.

planish finish A bright smooth finish on a
metal; usually obtained by beating the metal with
a special hammer or by passing it through rollers.

plank A long, wide, square-sawn thick piece of
timber; the specifications vary, but often the
minimum width is 8 in. (20 cm), and the mini-
mum thickness is 2 to 4 in. (5 to 10 cm) for soft-
wood and 1 in. (2.5 cm) for hardwood.

plank fence Same as board fence.

plank frame l.Any framework consisting
only of nailed planks. 2. A frame construction
consisting of girts, plates, posts, and sills as bear-
ing members and heavy planks as nonbearing
partitions and walls.

plank- frame house A type of 17th-century
colonial house constructed of heavy wood
planks, usually erected vertically by setting them
into grooves in a sill plate, 1 for support; they
were then drilled and pegged at their lower ends,
or otherwise held firmly in place.

plank house A large house, generally rect-
angular, constructed of planks; used and built by
Indians and, less frequently, by Eskimos.

planking 1 . A flooring surface or covering
made of planks. 2. The laying of planks. 3. See
decking. 4. In log cabin construction, a term
occasionally applied to logs that have been
hewn only on two opposite sides.

planking and strutting Temporary timbers at
the side of an excavation.

plank-in-the-ground construction See
plaunch debout en terre construction.

plank-on-edge floor, solid-wood floor A

floor formed by joists in contact with one another

planking, 1

(rather than spaced apart), their upper edges
forming a continuous surface upon which finish
flooring is applied.

plank truss A roof truss constructed of planks.

plank-type grating An aluminum extrusion
used primarily as a structural flooring member
and consisting of a tread plate reinforced by inte-
gral I-beam ribs, with perforations in the tread
plate between the ribs.

planned development A residential or com-
mercial area which is developed, maintained,
and operated as a single entity.

planned maintenance The maintenance of a

building, and/or its contents, on a schedule that
is determined by the results of past experience
and performance. Also called scheduled mainte-
nance. Compare with corrective maintenance,
periodic maintenance, and preventative mainte-
nance.

planning 1 . The process of studying the layout
of spaces within buildings and of buildings and
other facilities or installations in open spaces in
order to develop the general scheme of a build-
ing or group of buildings. 2. See community
planning.

planning grid An arrangement of one or more
sets of regularly spaced parallel lines, with the sets
at right angles or other selected angles to each
other, and used like graph paper by architects and
engineers to assist with modular planning.

plano-convex A shape of sun-dried brick, flat
on one side, convex on the other, typical of early
Mesopotamian construction.

plantation house The principal house of a
plantation in the antebellum American South,
typically having many of the following character-
istics: two stories; a projecting two-story portico
with Classic columns and a recessed central bay;
thick brick walls at ground level (often stuccoed);

736

plaster

plantation house: Drayton Hall, South Carolina

in areas having a high water table, a raised base-
ment, which often served as the location for ser-
vice facilities, pantries, a wine cellar, servants'
rooms, and sometimes for a dining room; a spa-
cious veranda extending along the facade at the
second-story level where the air circulation was
much better than at ground level, and often along
the sides and the back as well; many tall French
windows for cross-ventilation.

plant containerization The encasement of a
growing plant, together with its root system, in a
container.

planted In joinery and plastering, fabricated or
made on a separate piece of stuff; afterward fixed
in place, as a planted molding.

planted molding, applied molding A mold-
ing which is nailed, laid on, or otherwise fastened
to the work rather than cut into the solid material.

planted stop, loose stop A fillet or molding
which is nailed to a doorframe, window frame, or
lining, against which a door or casement is
stopped; a stop, 1.

planter A permanent, ornamental container to
receive planted pots or boxes, often nonmovable
and integral with the finish of a building.

planting In masonry, laying the first courses of a
foundation on a level bed.

planting box A box, usually wooden, designed
to hold growing plants and to fit inside a perma-
nent receptacle.

plant mix 1. Any mixture produced at a mix-
ing plant. 2. A mixture, produced in an asphalt
mixing plant, consisting of a mineral aggregate

uniformly coated with asphalt cement or liquid
asphalt.

plant room Same as mechanical room.

plasma arc cutting The cutting of metal by
use of an electric arc that concentrates a jet of
hot, ionized gas within a highly localized area.

plaster screed Same as screed, 3.

plaster stop A strip of metal placed along the
corner of a wall before plastering; serves as a
guide for plastering and as a reinforcement at the
corner.

plasticizer An admixture used with concrete or
mortar mix to make it workable with relatively
little water.

plate rail, plaque rail A narrow shelf or rail
along the upper part of a wall of a room; usually
grooved to support plates that are on display.

platform floor A raised floor, usually designed
to provide convenient access to cables beneath
the floor.

platform lift A special type of elevator that

raises or lowers a person over a small vertical dis-
tance; especially used where required by the
Americans with Disabilities Act or where a ramp
or conventional elevator would be impractical.

plating A thin coating of one metal on another.

plaque A tablet that is affixed to the surface of a
wall or set into a wall; often inscribed to commem-
orate a special event or to serve as a memorial.

plaque rail See plate rail.

plaster Usually a mixture of gypsum or lime
with sand and water, producing a paste-like
material that is applied in the plastic state, usu-
ally over lath fastened to a surface such as a wall
or ceiling, or sometimes directly onto brick; it
forms a hard surface when the water it contains
evaporates. In some remote early settlements,
when lime or gypsum was not available, a so-
called plaster of fine white clay mixed with
chopped straw was sometimes troweled onto a
surface to produce a smooth finish on a wall or
ceiling. Cow hair, cow dung, and/or chopped
straw often was added to the plaster mixture to
increase its mechanical strength when it dried.
Gypsum later supplanted lime as the plaster of
choice because of its superior properties. Also
see mud plaster, ornamental plaster, plaster of
paris, and stucco.

737

plaster aggregate

plaster aggregate Graded mineral particles
and/or wood fibers for mixing with gypsum and
cement-base plasters and with finish plaster to
produce plaster mixes.

plaster arch An untrimmed plaster opening.

plaster base Any suitable surface for the appli-
cation of plaster, such as gypsum lath, metal lath,
wood lath, masonry block, or brick.

plaster-base finish tile Ceramic tile whose
surfaces are intended for the direct application
of plaster; may be smooth, scored, combed, or
roughened.

plaster»base nail Same as gypsum-lath nail.
plaster bead, plaster head, plaster staff A

metal angle bead that is a built-in edging, rein-
forcing a plaster angle; a corner bead.
plasterboard Same as gypsum lath.

plasterboard nail A gypsum-lath nail; has a

flat head, mechanically deformed shank, and
diamond point.

GYPSUM
LATH

PLASTER

plasterboard nail

PLASTER GROUND

plaster ground

plaster lath See metal lath, gypsum lath, etc.
plaster of paris, hemihydrate plaster 1.

Calcined gypsum, containing no additives to con-
trol the set; a rapid-setting plaster used mainly for
ornamental casting. 2. Gauging plaster.
plaster ring A cylindrical metal ring, set in a
plaster ceiling, which serves as a guide for plas-
tering to a given thickness; also serves as a fas-
tener for trim.

plaster bond The adhesion of plaster to a sur-
face by a mechanical bond, 1 or a chemical
bond.

plaster ceiling panel A raised or sunken sec-
tion of a ceiling, forming a panel.

plaster cornice A plaster molding where the wall
and ceiling meet, crowning the top of the wall.

plaster cove A plastered concave surface at
the wall-ceiling junction.

plasterer's putty See lime putty.

plaster ground (usually pi.) A wood strip,
metal bead, or screed attached around a door,
window, etc., as a guide for plastering to a given
thickness; also serves as a fastener for trim; a
ground, 2.

plaster guard On a hollow metal doorframe, a
shield attached behind the hinge and strike rein-
forcement to prevent mortar or plaster from
entering the mounting holes when the frame is
grouted.

plaster head A plaster bead.

plaster ring

plaster set See false set.

plaster staff See plaster bead.

plaster wainscot cap A horizontal wood strip
which covers the joint between wainscoting and
the float finish surface above.

plasterwork l.Cast ornamental plaster, com-
monly cast with plaster of paris, typically on a
ceiling. 2. Any surface finished with plaster.

plastic 1. A natural or artificially prepared organic
polymer of low extensibility, as compared with rub-
ber; can be molded, extruded, cut, or worked into a
great variety of objects, rigid or nonrigid, relatively
light, which are formed by condensation poly-
merization and by vinyl polymerization; plastics.

738

plastic wood

plasterwork, 1

2. Characteristic of concrete, mortar, or plaster

which is easily spread with a trowel.
plastic cement A flashing cement,
plastic conduit Plastic conduit or tubing used

to enclose electric wiring.
plastic consistency The condition of freshly

mixed cement paste, mortar, or concrete such

that deformation will be sustained continuously

in any direction without rupture.
plastic cracking Cracking that occurs in the

surface of fresh concrete soon after it is placed

and while it is still plastic.
plastic deformation See plastic flow,
plastic design Same as ultimate-strength design.
plastic emulsion A latex emulsion.
plastic filler Same as plastic wood.
plastic floor covering See vinyl-asbestos tile,
plastic flooring See vinyl tile.
plastic flow, plastic deformation The

deformation of a plastic material beyond the

point of recovery, accompanied by continuing

deformation with no further increase in stress;

results in a permanent change in shape.

plastic foam See foamed plastic.

plastic glue A synthetic resin glue; also see
epoxy.

plasticity 1 . That property of freshly mixed
cement paste, concrete, mortar, or soil which
determines its resistance to deformation or its
ease of molding. 2. The ability of a plaster or
lime putty to hold or retain water, so that it can
be troweled easily.

plasticity index Numerical difference be-
tween the liquid limit and the plastic limit.

plasticizer 1 . An additive that increases plas-
ticity of a cement paste, mortar, or concrete mix-
ture. 2. An additive in a paint formulation to
soften the film, thus giving it better flexibility,
chip resistance, and formability. 3. A chemical
agent added to a plastic composition to improve
its flow and processability and to reduce brittle -
ness.

plastic laminate Multiple layers of resin-
impregnated paper, fused together under heat
and pressure to form a hard, durable (often dec-
orative) finished surfacing material.

plastic limit The lowest water content at
which a soil becomes plastic.

plastic loss Same as creep.

plastic mortar A mortar of plastic consistency.

plastic paint, texture-finished paint, tex-
tured paint A heavy-bodied, thixotropic
paint which can be worked after application, by
stippling or by paint rollers having a textured
pattern, to produce various textured or pattern
surfaces.

plastic pipe Pipe formed from a material that
contains one or more organic polymeric sub-
stances. Advantages may include: low initial
cost, light weight, high flexibility, good corro-
sion resistance, and availability in long lengths.
Disadvantages generally include: poor fire resis-
tance, production of toxic gas upon combus-
tion of some types of plastics, poor resistance to
solvents, low pressure ratings at high tempera-
tures, and (in some plastics) the susceptibility
to change as a result of prolonged exposure to
sunlight.

plastics See plastic, 1 .

plastic shrinkage cracks See hairline cracking.

plastic skylight See molded plastic skylight.

plastic soil A soil exhibiting plasticity.

plastic structural cladding Plastic panels
which are fastened directly to and supported by
roof or wall framing, forming a finished roof or
wall surface.

plastic 'wood A putty-like, rapid-drying filler;
composed primarily of nitrocellulose and wood
flour dispersed in volatile solvents; used for
repairing holes and cracks in wood.

739

plastic yield

plastic yield Same as plastic flow.

plastigel A plastisol to which a gelling agent
has been added to increase its viscosity.

plastisol A plastic resin, such as a vinyl resin,
which has been dissolved in a plasticizer; a
pourable liquid, used for casting; solidifies when
baked.

plat A map, plan, or chart of a city, town, sec-
tion, or subdivision, indicating the location and
boundaries of individual properties.

platband l.Any flat, rectangular, horizontal
molding, the projection of which is much less
than its height; a fascia. 2. A decorative lintel or
false flat arch over a doorway, etc. 3. The fillets
between the flutes of a column; stria.

plate 1 . A thin, flat sheet of material. 2. In wood
frame construction, a horizontal board or timber
connecting and terminating posts, joists, rafters,
etc. 3. A timber laid horizontally (and on its
widest side) in a wall or on top of a wall or on the
ground to receive other timbers or joists. Also see
ground plate, wall plate, partition plate, pole
plate, sill plate. 4. Plated metalware. 5. A flat,
rolled-metal product having the following
dimensions: hot-rolled steel, minimum thickness
0.18 in. (0.46 cm) and a width exceeding 6 in.
(15.2 cm); stainless steel, minimum thickness
Yi6 in. (0.48 cm) and a width exceeding 10 in.
(25.4 cm); aluminum, minimum thickness 0.25
in. (0.64 cm), no minimum width specified; cop-
per alloys, thickness exceeding Vk, in. (0.48 cm)
and a width greater than 12 in. (30.5 cm). Also
see crown plate, curtail plate, false plate, gallery
plate, head plate, pole plate, rafter plate, raising

plate, roof plate, sill, sill plate, soleplate, top plate,
wall plate.

platea In ancient Rome, a wide passageway or a

wide street.
plate anchor See sill anchor.
plate beam See plate girder.

plate bolt A bolt in a building foundation
which secures the plate or sill.

plate, 2

plate bolt

plate cut See seat cut.

plated parquet Parquetry having inlaid hard-
wood pieces applied to a framed backing.

plated truss A wood truss assembly in which
the truss joints are held together and reinforced
with steel plates.

plate girder, plate beam A steel girder built
up of plates and angles (or other structural
shapes), welded or riveted together.

plate glass A high-quality glass sheet having
both its flat sides plane and parallel so that it is
free of distortions and flaws; has much greater
mechanical strength than ordinary window
glass; usually formed by a rolling process, then
ground and polished, but can also be formed by
the float-glass process, in which molten glass
floats on a layer of molten metal to smooth out
surface irregularities, producing a flat sheet of
glass when the temperature of the molten metal
is gradually reduced.

plate rail, plaque rail A narrow shelf or rail
along the upper part of the walls of a room,
grooved to hold chinaware plates or decorations.

Plateresque architecture A richly decora-
tive style of Spanish architecture of the 16th

740

playhouse

century; said to resemble the intricate work of
Spanish silversmiths in delicacy, hence its name
(plata is the Spanish word for silver). Particularly
applied to many Spanish Colonial buildings
in the Americas from the 16th into the 18th
centuries.
plate tracery Tracery whose openings are or
seem to be pierced through thin slabs of stone.

plate tracery

plate-type tread A tread, or a combination of
tread and riser, fabricated from metal plate, floor
plate, tread plate, or some combination of such
plates.

plate vibrator A mechanically driven tamper
having a flat base.

platform l.A raised floor or terrace, open or
roofed. 2. A stair landing; also see stair platform.
3. A grillage.

platform framing A system of framing for a
building of wood construction several stories
high, in which the studs are only one story high;
the floor joists for each story rest on the top
plates of the story below or on the soleplate of
the first story; the bearing walls and partitions
rest on the subfloor of each story, i.e., rest on the
rough floor that serves as the base for the finish
floor. Also called western framing. Compare
with balloon framing.

OJ LOWER-FLOOR
TOP PLATE

SOLE
PLATE

platform frame

platform framing, western framing A

method of timber building construction making
use of a platform frame.

platform header A horizontal structural
member which supports a stair platform con-
struction but carries no stringers.

platform ladder A ladder which is self-sup-
porting and has a platform at the working level.

platform roof A roof which terminates in a
horizontal plane; any roof which is truncated.

platform stair Same as dogleg stair.

platted molding Same as reticulated molding.

plaunch debout en terre construction In
French Vernacular architecture a system of
construction, once widely used in Southern
Louisiana, in which closely spaced planks were
driven several feet into the ground; the space
between the planks was filled with bousillage, then
the wall was covered with horizontal clapboards.

play The separation between moving parts to
reduce friction.

playfield An area designed for field games.

playhouse 1. A place of assembly for dramatic
presentations. 2. A small building serving chil-
dren as a make-believe home.

741

play lot

play lot A playing area for children.

plaza A public square that is usually centrally
located, in Spain and in communities of Spanish
heritage.

pleach The intertwined branches of a line of
trees that form a barrier.

pleached Said of the branches of trees, shrubs,
vines, etc., which are united by weaving, braid-
ing, or plaiting.

pleasance A pleasure garden intended for
enjoyment; often secluded.

pleasance chamber In a royal palace, a room
of state.

plenishing nail A large nail for fastening the
planks of floors to the joists.

plenum l.In suspended ceiling construc-tion,
the space between the suspended ceiling and the
main structure above. 2. A plenum chamber.

plenum barrier In suspended ceiling con-
struction, a material or structural barrier erected
in a plenum over a partition; used to reduce
sound transmission between adjoining rooms by
way of this path over the partition.

plenum cable A jacket having low flame- and
smoke-producing properties; specifically de-signed
for use in the plenum, 1 formed by the space
between a suspended ceiling and the structural
floor above; such space often is used for return air
in a heating and/or cooling system in a building.

plenum chamber In an air-conditioning sys-
tem, an enclosed volume which (in a supply sys-
tem) is at a slightly higher pressure than the
atmosphere and is connected to a number of
branch supply ducts, or which (in a return sys-
tem) is at a slightly lower pressure than the
atmosphere and is connected to a number of
return grilles; a plenum, 1.

plenum fan A backward-curved airfoil impel-
ler that is housed in a rectangular plenum; has
ducted inlet and outlet connections; it is not
enclosed in a typical volute scroll.

plexiform Having the appearance of network,
weaving, or plaiting, as in Celtic and Roman-
esque ornamentation.

Plexiglas The proprietary name for a transpar-
ent weather-resistant acrylic sheet.

plf Abbr. for "pounds per linear foot."

PLG On drawings, abbr. for piling.

plenum fan

pliers A hand tool, pincer-like, with scissors
action, usually with serrated jaws; used for grip-
ping, holding, bending, and cutting.

plinth 1 . A square or rectangular base for column,
pilaster, or door framing. 2. A solid monumental
base, often ornamented with moldings, bas reliefs,
or inscriptions, to support a statue or memorial.
3. A recognizable base of an external wall, or the
base courses of a building collectively, if so treated
as to give the appearance of a platform.

PLINTH

plinth, 1

plinth block See skirting block.

plinth brick A brick having a chamfer, 4 on its

face or on one of its ends; usually used as one of
the bricks in a plinth course.
plinth course 1 . A masonry course which
forms a continuous plinth. 2. The top course in a
brick plinth.

plinth course of brick

PLMB On drawings, abbr. for plumbing,
plot l.A parcel of land consisting of one or
more lots or portions thereof, which is described

742

plumb bond pole

by reference to a recorded plat or by survey. 2. A
small area of ground.

plot ratio Same as floor area ratio.

plough See plow.

ploughshare vaulting A vaulting, 1 in which
masonry stretchers are laid in a series of rough
triangles.

plow, plough l.A carpenter's plane which
cuts grooves. 2. A router. 3. See groove.

plow and tongue joint Same as tongue-and-
groove joint.

plowed bead Same as quirk bead, 2.

plow groove A groove on the edge of a board,
esp. for a tongue-and-groove joint.

plowshare twist, plowshare vault A vault
in which the surface between the stilted wall rib
and the diagonal rib is warped like a plowshare.

plow strip A strip of wood having a groove run-
ning along the edge, esp. used to fix the edge of
a drawer bottom.

plucked finish A stone surface which is rough
in texture; produced by setting a planer blade so
deep that it removes stone by spalling rather
than by shaving.

plug l.A small cylinder or dowel of wood (or
other material) driven into a wall, to which a fas-
tener is fixed. 2. A small piece of wood, plywood,
veneer, etc., fitted into a recess to patch a defect;
an insert or patch. 3. A fibrous or resinous mate-
rial used to fill a void and otherwise patch a sur-
face. 4. In plumbing, a drain-opening stopper; a
fitting for closing the end of a pipe. 5. A recepta-
cle plug. 6. An attachment plug. 7. A device for
connecting wires to a jack. 8. A circular core of
sod used in maintaining a lawn.

plug, 4

plug center bit A center bit ending in a small
cylindrical plug instead of a point; used to
enlarge a hole previously made or to form a
counterbore around it.

plug cock Same as ground-key faucet.

plug cutter A small bit, 1 operated by a power
drill, for cutting out plugs used to cover recessed
screwheads in a hardwood floor.

plug-driving gun A stud gun.

plug fan Same as plenum fan.

plug fuse 1 . A fuse mounted in an insulated
porcelain container fitted with a threaded,
metal screw base; has a small window on the
face of the fuse for observing the condition of
the fuse element. 2. An Edison-base fuse or a
type-S fuse.

plug fuse

plugging Filling a hole, drilled in masonry, with
a fiber, plastic, or wood plug into which a screw
can be driven.

plugging chisel, plugging drill Same as star
drill.

plugmold Same as baseboard raceway.

plug tap Same as ground-key faucet.

plug tenon Same as stub tenon.

plug valve Same as ground-key valve.

plug weld A weld made through a circular hole
in one member of a lap joint, 2 or tee joint, join-
ing one member to the other.

plum, plum stone A large random-shaped
stone which is dropped into freshly placed mass
concrete to economize on the amount of con-
crete mortar required.

plumb Exactly vertical.

plumbago Same as graphite.

plumb bob, plummet A shaped metal weight
which is suspended from the lower end of a line
to determine the vertical. (See illustration p. 744-)

plumb bond In masonry, any bond in which
the vertical joints are precisely in line.

plumb bond pole In masonry construction, a
pole used to ensure that the vertical joints are
plumb.

743

plumb cut

plumb bob

plumb cut, ridge cut A cut in a vertical plane,
as the cut on a rafter where it butts vertically
against a ridgeboard.

plumber's friend, force cup, plumber's
helper, plunger A tool consisting of a rubber
suction cup attached to a handle; set over a plumb-
ing trap (or the like) and worked with a pumping
action to clear the trap of minor obstructions.

plumber's furnace A portable gasoline-fired
heater; used by plumbers to melt solder or lead,
or to heat soldering irons, etc.

plumber's rasp A coarse rasp, esp. used by
plumbers to file lead.

plumber's round iron A soldering iron used
by plumbers to solder seams in tanks.

plumber's soil A mixture of lampblack, glue,
and water; painted on the surface of a pipe, outside
a joint, to prevent solder from adhering; used to
ensure a clean edge in wiped joints.

plumber's solder A soft solder containing
approximately two parts of lead to one part of
tin; used in making wiped joints and seams.

plumber's union See union, 1.

plumbing l.See plumbing system. 2. The

work or business of installing in buildings the
pipes, fixtures, and other apparatus for bringing
in the water supply and removing liquid and
waterborne wastes.

plumbing appliance A class of plumbing fix-
tures intended to perform a special function; their
operation may depend on the setting of controls or
on the characteristics of heating elements, motors,
or pressure- or temperature-sensing elements.

plumbing appurtenance A manufactured
device or assembly of prefabricated components
which act as an adjunct to the basic piping sys-
tem and plumbing fixtures; usually performs a
useful function such as operating, maintaining,
or servicing the plumbing system; does not add
either to the water demand or to the discharge
load of fixtures or of the drainage system.

plumbing conduit Same as conduit, 2.

plumbing fitting Same as fitting, 1.

plumbing fixture A receptacle which receives
and discharges water, liquid, or waterborne
wastes into a drainage system with which it is
connected.

plumbing official The officer or other desig-
nated authority charged with the administration
and enforcement of the applicable plumbing code.

plumbing riser A riser, 4 for pipes that run verti-
cally; usually extends the full height of a building.

plumbing system The combination of supply
and distribution pipes for hot water, cold water,
and gas, and for removing liquid wastes in a
building; includes: the water-supply distributing
pipes; the fixtures and fixture traps; the soil,
waste, and vent pipes; the building drain and
building sewer; and the storm-drainage pipes;
with their devices, appurtenances, and connec-
tions all within or adjacent to the building.

plumbing trap See trap, 1 .
plumbing trim See trim, 3.

plumbing up Ensuring that a building frame-
work is plumb.

plumb joint In sheet-metal work, a joint made
by lapping the edges and soldering them
together flat.

plumb level, pendulum level A level con-
sisting of a bar and a plumb line; the bar is set in
true horizontal position by placing it at a right
angle to the plumb line.

plumb line A cord or line, having a metal bob
or weight attached to one end, which indicates
the true vertical direction.

plumb pile A pile which is vertical.

744

pneumatic structure

plumb rise The overall vertical measurement
at the end of a truss where the top and bottom
chords meet.

plumb rule A narrow board with parallel edges
having a straight line drawn through the middle
and a string attached at the upper end of the
line; used by carpenters, masons, etc., for deter-
mining a vertical.

plumb rule

plume Wood veneer having a large featherlike
figure, usually cut from a crotch.

plummet A plumb bob.

plum stone A plum.

plunger See plumber's friend.

plunger hydraulic elevator A hydraulic
elevator in which the piston (called a "plunger")
is attached directly to the car frame or platform;
the driving mechanism includes the cylinder,
piston, pump, and associated valves.

plus sight Same as backsight.

pluteus 1. A low barrier placed between
columns. 2. A screen of pierced marble which
surrounds the choir or sanctuary of a church.

ply One of a number of thin sheets in a layered
construction, as in plywood, laminated panels,
roofing felt, etc.

5 PLY

ply

plyglass Same as laminated glass.

plymetal Plywood clad on one or both sides
with sheet metal.

ply plastic Same as molded plywood.

PLYWD On drawings, abbr. for plywood.

plywood Structural wood made of three or
more layers of veneer (usually an odd number),
joined with glue; usually laid with the grain of
adjoining plies at right angles.

plywood squares, plywood parquet Ply-
wood esp. fabricated for use as flooring; has an
exposed face veneer of birch, oak, or other ser-
viceable hardwood.

PNEU On drawings, abbr. for "pneumatic."

pneumatically applied concrete See shot-
crete.

pneumatically applied mortar See shotcrete.

pneumatic caisson Same as caisson, 1.

pneumatic control system A system in which
control is effected by air, under pressure; e.g., an air-
conditioning system controlled by pneumatically
operated thermostats or humidistats.

pneumatic dispatch system See pneumatic
tube system.

pneumatic drill A drill powered by com-
pressed air from an auxiliary external source.

pneumatic ejector A special type of device
designed to receive and dispose of liquids and
sewage from subbuilding drainage systems.

pneumatic feeding The delivering of shot-
crete with equipment which moves the material
by means of a pressurized air stream.

pneumatic hammer See air hammer.

pneumatic mortar Same as shotcrete.

pneumatic placement Of concrete, slurry, or
plaster, etc.: delivery by piping or hose to the final
location on a jobsite; the material may be pumped
in its normal wet consistency, either for deposit in
place or for spraying, or its constituents may be
pumped in the dry state with water added at the
nozzle from which it is sprayed.

pneumatic riveter A tool, driven by com-
pressed air, which is used to drive rivets.

pneumatic structure A very lightweight en-
closed structure, usually fabricated of a mem-
brane of an impervious material and supported by
the difference in air pressure between the exte-
rior and the interior of the structure rather than

745

pneumatic test

by a structural framework. Fans must maintain
the interior pressure slightly in excess of normal
atmospheric pressure to prevent the structure
from slowly deflating and collapsing. Used pri-
marily as a temporary enclosure or to house sports
facilities such as tennis courts and swimming
pools. Also called an air-supported structure.

pneumatic test See air test.

pneumatic tube system A system for send-
ing small items or papers from one location to
another in a building. The item to be sent is
placed in a small cylinder that fits snugly in a
tube that connects the two locations. Then, the
cylinder moves rapidly through the tube to its
destination as a result of a force provided by air
pressure or a vacuum.

pneumatic water supply A building water-
supply system in which water is distributed from
an enclosed storage tank containing water and
compressed air; system pressure is maintained by
the compressed air.

PNL On drawings, abbr. for panel.

Pnyx A public place of assembly in ancient
Athens near the Acropolis; an open, paved,
semicircular area surrounded by a wall; speakers
addressed the people from a platform.

PO Abbr. for "purchase order."

poche In an architectural drawing, the black-
ened portions representing solids.

pocket l.A recess in masonry to receive the
end of a beam. 2. The slot in the pulley stile of a
double-hung window frame, through which the
sash weight is passed into the sash weight chan-
nel; a sash pocket. 3. A recess at the head or
jamb of a wall opening to receive a curtain. 4. A
recess in the interior jamb of a window to
receive a folding shutter when open. 5. A recess
in a wall to receive a folding door in the open
position. 6. See stage pocket. 7. A well-defined
opening between the annual rings which devel-
ops during the growth of a tree.

pocket butt A type of butt hinge mounted on
the third leaf of three-ply inside shutters; permits
the leaf to enter its pocket, 4 without jamming.

pocket chisel Same as sash chisel.

pocket door A door that slides into a hollow
wall at the side of a doorway; often advantageous
because such a door requires no room for swing-
ing; may be single or biparting.

pocket door

pocket-head window A window in which a
part of the sash slides upward through an open-
ing in the head of the window frame.

pocket piece In a double-hung window frame,
a small wood piece in the pulley stile which may
be removed to insert sash weights or to replace
the sash cord.

pocket rot A type of decay in trees consisting
of holes (pockets) surrounded by sound wood.

pockmarking An undesirable depression in a
paint film. Also see cratering, pitting, pinhole, 3.

podium 1. In general, a raised platform for a
speaker. 2. The high platform in an early Roman
temple. 3. A socle projecting from the base of a
building. 4. A low, step-like projection from the
wall of a room or building that forms a raised
platform on which objects can be displayed.

poecile A stoa or porch on the agora of ancient
Athens having walls adorned with paintings of
historical and religious subjects.

poikile Same as poecile.

point l.See glazier's point. 2. A mason's tool;
see wasting. 3. See pointing.

point load A load concentrated over a tiny area.

point-bearing pile Same as end-bearing pile.

pointed arch Any arch with a point at its apex,
characteristic of, but not confined to, Gothic
architecture.

pointed architecture Characterized by Gothic
arches.

pointed ashlar Stonework having face mark-
ings produced with a pointed tool.

746

point of support

pointed arch

pointed dormer Any dormer having a point
at its apex.

pointed pediment A pediment having a tri-
angular shape; also called a triangular pediment.

Pointed style A seldom-used term for Gothic
Revival.

pointed 'work In masonry, the rough finish
that is produced on a stone by repeated impacts
of a pointed tool striking its face.

pointed work

pointel, pointelle 1 . A pattern in a pavement,
formed by small squares or lozenges laid diago-
nally. 2. Any similar pattern.

pointing 1. In masonry, the final treatment of
joints by the troweling of mortar or a putty-
like filler into the joints; also see flush point-
ing, recessed pointing, tuck pointing. 2. The
material with which the joints are filled. 3.
The removal of mortar from between the joints
of masonry units and the replacing of it with
new mortar; repointing. 4. In stone carving,
creating points from a model and establishing
their position on the stone that is to be carved.

pointing trowel A mason's trowel used in
pointing or removing old mortar from masonry
joints.

pointing trowel

point of contraflexure Same as point of
inflection.

point of delivery Same as point of service, 3.

point of inflection The point on the length of
a structural member subjected to flexure at
which the direction of curvature changes and at
which the bending moment is zero.

point of service 1 . The location at which
service cables installed by an electrical utility
company joins the customer's service entrance
conductors in one or more terminating enclo-
sures. 2. The location at which a customer's
service entrance conductors joins the electri-
cal utility company's facilities in a transformer,
vault, or enclosure. 3. The initial junction of
the customer's gas piping with either the gas
company's piping extending from the gas main
and/or the regulator which reduces the pres-
sure of an undiluted liquefied petroleum gas to
the pressure normally delivered to appliances.

TYPICAL
POINT OF
DELIVERY

NATUHiL
GfiS

UTILIZATION
EQUIPMENT

point of service, 3

point of support The point on a member
where its load is transmitted to a support.

747

point-of-use heater

point-of-use heater An instantaneous-type
water heater in a remote location far from other
fixtures using hot water.

point source A light source whose dimensions
are insignificant compared with the distance at
which it is used; e.g., a fluorescent lamp is a point
source when viewed from a large distance but a
line source when viewed close to the source.

Poisson's ratio In a material under tension or
compression, the absolute value of the ratio of
transverse strain to the corresponding longitudi-
nal strain.

poker vibrator See vibrator.

POL On drawings, abbr. for "polish."

polarized receptacle An electric receptacle
having contacts arranged so that a mating plug
can be inserted in it in only one orientation.

polarized receptacle

pole A long, slender, tapering piece of wood; a
pale, prop, stake, or stay.

pole footing A type of construction in which a
pole is embedded in the ground and extends
upward to serve as a column.

pole foundation A foundation system using
wooden poles, partly buried in excavated holes,
for both lateral and vertical support.

pole-frame construction Same as bent-
frame construction.

pole piece A ridgeboard.

pole plate A horizontal timber resting on the ends
of the tie beams of a roof; supports the lower ends
of the common rafters, directly above the wall;
raises the rafters above the top plate of the wall.

pole-platform construction A pole-founda-
tion structure in which the tops of the poles
extend above the surface of the ground and sup-
port a platform; this platform acts as the base for
a building superstructure.

pole-type transformer A transformer suit-
able for mounting on a pole or similar structure.

Utility company lire

Pole- type transformer
(supplied by company!

Transformer secondary
wire (installed by
customer)

Conduit or raceway

Meter and its socket

M EC-approved grounding

Sign "Danger
High Voltage
Keep Off"

Finished grade
pole-type transformer

pole wall A type of wall constructed of a series
of vertical wood poles.

poling board (Brit. ) One of a number of verti-
cal boards in open sheeting.

polish In plastering, to give a sheen or gloss to
the finish coat.

polished finish In stonework, a finish so
smooth that it forms a reflecting surface; usually
obtained by chemical treatment and prolonged
mechanical buffing of a stone surface on which
there are no voids.

polished plate glass Plate glass that has been
ground and polished on both sides.

polished work Stonework that has been pol-
ished to a mirror-like finish with an abrasive.

polish grind, final grind In concrete work,
the final operation, in which fine abrasives are
used to hone a surface to its desired smoothness
and appearance, as for terrazzo concrete.

polishing varnish, rubbing varnish A
hard varnish which can be polished by rubbing
with an abrasive and mineral oil.

poll The broad end or striking face of a hammer.

748

polythene

pollution The action of degrading an environ-
ment by discharging harmful substances into
the air, soil, or water, or by increasing noise to
an unacceptably high level, so that the site is
less desirable for (or is harmful to) residential,
commercial, or social purposes.

polyamide A polymer; the most widely known
in this group is nylon.

polychromatic finish l.A multicolored
paint finish. 2. A paint containing reflecting
metallic flake and fine transparent pigments
which appear as a variety of colors when viewed
from different angles.

polychrome brickwork The use of brick-
work in a variety of colors, often to provide dec-
orative architectural designs.

polychromed l.Said of a building facade
exhibiting a distinctive masonry pattern of con-
trasting colors, usually in the form of horizontal
bands across the facade and/or bands around
arches, doorways, or windows; a feature of the
latter phase of High Victorian Gothic. 2. Said of
surfaces (such as pipes or ducts) that are painted
different colors, often to indicate their respec-
tive functions.

polychromy The practice of decorating archi-
tectural elements, sculpture, etc., in a variety of
colors.

polyester resin One of a group of synthetic
resins which undergo polymerization during cur-
ing; advantageous because high pressure is not
required for curing; has excellent adhesive proper-
ties, high strength, good chemical resistance; esp.
used in laminating and impregnating materials.

polyethylene A thermoplastic material often
used in electrical insulation or in sheet form for
dampproofing.

polyfoil Same as multifoil.

polygonal masonry Masonry which is con-
structed of stones having smooth polygonal faces.

polygonal roof See pavilion roof, 2.

polymer One of a group of high-molecular-
weight resin-like, organic compounds whose
structures usually can be represented by repeated
small units. Some polymers are elastomers, some
are plastics, and some are fibers.

polymer-cement concrete Concrete pro-
duced by a mixture of hydraulic cement, aggre-
gate, water, and a polymer or a monomer.

polygonal masonry

polymer concrete Concrete in which an
organic polymer is used as the binder.

polymeric poured floor A floor covering
which is composed of a polymeric material
poured on a substrate; converts to a thick built-
up floor covering; may incorporate mineral or
plastic chips, desiccants, fillers, or pigments.

polymerization A chemical reaction in which
the molecular weight of the molecules formed is
a multiple of that of the original substances.

polymer-modified stucco A stucco contain-
ing a small amount of acrylic resin to increase its
workability.

polymethyl methacrylate A polymer of
methyl methacrylate.

poly pipe A class of polymer pipes that provide
low resistance to the flow of a fluid within the
pipes; light in weight and low in electrical con-
ductivity.

polypropylene A plastic polymer of propy-
lene; a tough material having good resistance to
heat and chemical action.

polystyle Composed of many columns.

polystyrene foam See foamed polystyrene.

polystyrene resin A synthetic resin which is
formed by the polymerization of styrene upon
heating; uses include paint for concrete.

polysulfide rubber A synthetic polymer that
is resistant to light, oils, and solvents; particu-
larly useful as a sealant.

polytetrafluoroethylene A waxy opaque
thermoplastic resin commonly known by its
proprietary name Teflon; resistant to acid oxi-
dizing agents and to alkalis; has a particularly
slippery surface.

polythene Same as polyethylene.

749

polyurethane finish

polyurethane finish An exceptionally hard
and wear-resistant paint or varnish made by the
reaction of polyols with a multifunctional iso-
cyanate.

polyurethane foam A thermoplastic cellular
material especially used for thermal insulation in
buildings.

polyvinyl acetal A vinyl plastic produced
from the condensation of polyvinyl alcohol
with an aldehyde. There are three main groups:
polyvinyl acetal, polyvinyl butyral, and
polyvinyl formal; used in lacquers and adhe-
sives. Polyvinyl acetal resins are thermoplastics
which can be processed by casting, extruding,
molding, and coating.

polyvinyl acetate, PVA A colorless, ther-
moplastic, water-insoluble resin; used as a latex
binder in certain paints.

polyvinyl chloride, PVC A water-insoluble
resin thermoplastic resin that is highly resistant
to chemicals and corrosion; widely used for pipe
fittings, piping in cold-water systems, and piping
in sewage and waste lines.

pommel, pomel A rounded finial.

Pompadour style Same as Rococo.

ponded roof A roof designed to retain water
on the roof's surface to provide for evaporative
cooling.

ponding 1 . The accumulation of water in a
depression on an otherwise level surface. 2. The
process of flooding the surface of a newly placed
concrete slab with a thin layer of water to ensure
continued hydration; usually requires the use of
temporary dams of earth or other material
around the perimeter.

pontifical altar An isolated altar, such as
under the dome of St. Peter's at Rome, covered
by a baldachin; usually placed in the great
Roman basilicas.

pony wall Same as dwarf wall, 2.

pool See swimming pool.

poorhouse A building, often supported by a
community or by a religious organization, that
provide housing and minimal services for the
indigent; also see almshouse and bettering house.

poor lime Lime containing a significant pro-
portion of material that is insoluble in acids; not
a pure lime.

popcorn concrete A no-fines concrete which
contains insufficient cement paste to fill voids
between the coarse aggregate; the particles are
bound only at points of contact.

poplar See yellow poplar.

popout The breaking away of small portions of a
concrete surface, owing to internal pressure,
leaving a shallow, typically conical depression.

popping, blowing, pitting, pops Shallow
conical depressions, ranging in size from pin-
heads to diameters of V* in. (64 mm), just below
the surface of a lime -putty finish coat; caused by
the expansion of coarse particles of unhydrated
lime or of foreign substances.

poppyhead, poppy An ornament generally
used for the finials of pew ends and similar pieces
of church furniture.

poppyhead

population composition The distribution
within a group of people of specified individ-
ual attributes such as sex, age, marital status,
education, occupation, and relationship to the
head of household.

pop»up rod A metal rod on a washbasin which
controls the raising and lowering of the drain
stopper.

pop valve A safety valve designed to open
abruptly when the pressure exerted by the fluid
on the valve overbalances the force exerted by
a spring which normally keeps the valve
closed.
PORC On drawings, abbr. for "porcelain."
porcelain A glazed or unglazed vitreous ceramic
whiteware used for electrical, chemical, mechan-
ical, structural, or thermal components.

750

portal frame

porcelain enamel, vitreous enamel A sub-
stantially vitreous (glassy) inorganic metal oxide
coating, bonded to metal by fusion at a tempera-
ture above 800°F (427°C); not a true porcelain.

porcelain enamel ware See double-faced
ware.

porcelain tile A dense, fine-grained, smooth
ceramic mosaic tile or paver; has sharply formed
face, usually impervious; usually made by the
dust-pressed method. Colors of the porcelain
type usually are clear and luminous or a granular
blend thereof.

porcelain tube A ceramic tube having a slight
shoulder on one end; in exposed electric wiring,
used to carry an insulated conductor where it
passes through a wood joist, stud, etc.

porch 1 . An exterior structure that shelters a
building entrance. 2. An exterior structure that
extends along the outside of a building; usually
roofed and generally open-sided, but may also be
partially enclosed, screened, or glass-enclosed; it
is often an addition to the main structure; also
called a veranda, galerie, or piazza; if set within
the building structure, it is said to be an integral
porch. 3. A small vestibule inside the front door
of a 17th-century colonial American house, usu-
ally containing a steep stair leading to the loft
space above. Also see carriage porch, double-
decker porch, double-tiered porch, engaged
porch, full-facade porch, full-width porch,
gabled porch, inset porch, integral porch, lattice
porch, portale, projecting porch, raised porch,
shed-roof porch, sleeping porch, storm porch,
two-tiered porch, wrap-around porch.

porch

porch chamber A bedroom above an unheated
entrance porch or veranda of a house.

porch lattice Along the side of a porch or
veranda below floor level, an open lattice where
the foundation is not continuous.

porch rail A molded wood member extending
between columns or posts of a porch, veranda,
etc., and joining either the tops or bottoms of
the balusters.

porcupine boiler A vertical, cylindrical boiler
having many short dead-end tubes projecting
from the cylindrical surface to provide addi-
tional heating surface.

pore water The free water that is present in soil.

pore water pressure The pressure of water
which is present in saturated soil.

porosity A ratio, usually expressed as a percent-
age, of the volume of voids in a material to the
total volume of the material, including the voids.
The voids permit gases or liquids to pass through
the material.

porous fill Same as drainage fill.

porous pavement A pavement constructed of
a material that permits water to percolate through
it into the subgrade.

porous pipe A pipe that allows liquid or gas to
ooze through its walls; can be used as a subsoil drain.

porous 'wood Any hardwood having a struc-
ture which includes hollow tube-like cells called
"pores" or "vessels."

porphyry Igneous rock characterized by large
conspicuous crystals which are set in a matrix of
finer crystals; used as decorative stone and in
building construction.

porta The gate of an ancient Roman city.

portal 1 . An impressive or monumental entrance,
gate, or door to a building or courtyard, often dec-
orated. 2. A structural framework consisting of a
beam supported by two columns to which it is
connected with sufficient rigidity to hold virtually
unchanged the original angles between the inter-
secting members. (See illustration p. 752.)

portal crane A gantry crane.

portale In Spanish architecture and derivatives,
a covered porch, usually long and narrow, along
the front or side of a house, whose roof is sup-
ported by wood posts capped with bolsters, 1 ; pro-
vides direct access to individual room entrances.

portal frame Same as portal, 2.

751

PORT CEM

portal

PORT CEM On drawings, abbr. for portland
cement.

portcullis A defensive grating, of massive iron or
timber, movable vertically in retaining grooves
cut in the jambs of a fortified gateway.

fpiiimiji

iKfiHiTfKlSfl

porte cochere 1 . A carriage porch. 2. A covered
carriage or automobile entryway leading to a
courtyard.

porte cochere, 1

portcullis

porte cochere, 2

porteria 1. A porter's lodge. 2. The entrance to a
monastery; often an arcaded porch or a narthex
at one side of the church facade. 3. An arcaded
porch that serves as an entrance to a convento.

porthole Same as access door.

portico 1 . A covered entrance whose roof is
supported by a series of columns or piers, com-
monly placed at the front entrance to a building.
2. A stoa.

portico-in-antis A portico that is recessed
within a structure instead of projecting from the
facade; also see anta.

porticus l.Same as portico. 2. A side chapel;

common in many Anglo-Saxon churches and
usually used for burials of important people.

portigo Same as portico.
Portland blast-furnace slag cement, blast-
furnace slag cement l.An interground

752

post

portico

mixture of portland cement clinker and granu-
lated blast-furnace slag; type IS cement. 2. A
uniform blend of portland cement and fine gran-
ulated blast-furnace slag.

portland cement A cementitious binder used
in most modern structural concrete; manufac-
tured by grinding and "burning" a mixture of
limestone with clay or shale with a small amount
of gypsum. It is mixed with water and an aggre-
gate (such as sand and/or gravel) to form a thick,
heavy liquid that dries as a monolithic product.
Although cement was developed by the ancient
Romans, portland cement was first developed in
England in 1824; since then, its tensile strength
has greatly increased.

portland cement clinker A partly fused
clinker primarily consisting of hydrated calcium
silicates.

portland cement concrete See concrete.

portland cement paint See cement paint.

portland cement plaster A plaster which is a
portland cement (or a combination of such
cements) mixed with masonry cement or port-
land cement and lime; then mixed with an
aggregate.

portland cement stucco A type of stucco
that contains no acrylic; also called PC stucco.

portlandite A common product resulting from
the hydration of portland cement; calcium
hydroxite.

portland- pozzolan cement l.An inter-
ground mixture of portland cement clinker and
pozzolan; type IP cement. 2. A uniform blend of
portland cement and fine pozzolan.

Portland stone, Portland limestone An

oolitic limestone which is quarried on the Isle of
Portland, off the coast of England; widely used as
a building stone in London.

POS On drawings, abbr. for "positive."

posa 1. In 16th-century Hispanic church archi-
tecture, a processional oratory at each corner of
an atrium, 2. 2. A small chapel in the walled
forecourt of an early California mission.

posada In Spanish architecture and derivatives,
an inn.

positioned weld A weld made in a joint
which has been so placed as to facilitate the
making of the weld.

position indicator In an elevator system, a
device designed to indicate the position of a car
in its hoistway.

positive cutoff A cutoff, 2 which extends down-
ward to an impervious lower boundary, completely
blocking the path of subsurface seepage.

positive-displacement Descriptive of equip-
ment in which wet-mix shotcrete is delivered by
being pushed through the material hose in a
solid mass by a piston or auger.

positive heat supply Heat that is supplied to
a space with direct design intent, such as by
installed heating devices, or heat that is supplied
to a space indirectly, such as by means of uninsu-
lated surfaces of a furnace or boiler.

possum-trot cabin Same as dogtrot cabin.

possum-trot plan, dogtrot plan Log-cabin
plan of a house with two parts separated by a
breezeway, all under a common roof.

post A strong, stiff, vertical structural member
or column, usually of wood, stone, or metal,
capable of supporting a framing member of the
structure above it and/or providing a firm point
of lateral attachment. Posts may divide the
structural framework of a building into bays.
The term post may be preceded by an adjective
indicating its location (such as a corner post) or
by an adjective indicating its shape (such as a
musket-stock post). For definitions and illustra-
tions of specific types of posts, see angle post,
chimney post, corner post, crown post, doorpost,
flared post, gabled post, gate post, gun-stock post,
hanging post, jack post, jamb post, king post,
musket-stock post, prick post, principal post,

753

post-and-beam construction

shouldered post, splayed post, sure post, teagle

post, wall post.
post-and-beam construction See post-and-

lintel construction.
post-and-beam framing A type of framing

in which horizontal members rest on a post,

rather than resting on a wall.

ROOF BEAM

JOIST MANGER

post-and-beam framing

post-and-girt framing Since medieval times,
a system of structural wood-frame construction
characterized by the use of heavy corner posts,
horizontal girts to support the superimposed
loads, and summerbeams to support the floor
joists; largely replaced by balloon framing in the
early 19th century. Structural members were
interconnected by mortise-and-tenon joints
that were held fast by wood pins or dowels.

post-and-lintel construction A type of con-
struction characterized by the use of vertical
columns (posts) and a horizontal beam (lintel)
to carry a load over an opening — in contrast to
systems employing arches or vaults.

post and pane, post and petrail A system
of construction consisting of timber framings
filled in with brickwork or lath and plaster; half-
timbered construction.

post-and-rail construction A type of con-
struction characterized by the use of upright
posts that carry horizontal members to which
siding is attached.

post-and-rail fence A fence having a series of
posts set into the ground, usually interconnected
by several horizontal rails between consecutive
posts.

post-and-truss A type of construction charac-
terized by the use of vertical columns and trusses
that form bay-dividing cross-frames.

postbuckling strength The load which can
be carried by a structural member or by a plate
after it has been subjected to buckling.

Post-Colonial period A term sometimes
applied to the years in America from about 1 780
to 1830 during which time many buildings were
built in the Classical Revival style or Federal style.

post-completion services Additional ser-
vices rendered after issuance of the final certifi-
cate for payment, such as consultation regarding
maintenance, processes, systems, etc.

posted occupancy and use A sign for dis-
play, usually required by the applicable building
code, that indicates the legally acceptable num-
ber of occupants of a building; the code may also
require an indication of code-accepted usage,
floor load, and fire grade.

postern 1. A minor, often inconspicuous, entry.
2. A small door near a larger one. 3. Any
small door or gate, esp. one far from the main
gate in a fortified place. 4. Same as sally port.

postern, 2

postformed plywood Flat plywood that has
been reshaped into a new configuration, either by
the use of steam or the use of a plasticizing agent.

post hole A hole which is dug in the ground to
hold a fence post.

post house A house or inn along a post road
(i.e., a road over which mail was once carried)
with facilities for keeping horses and carriages
used by mail couriers and travelers.

754

poteaux-sur-solle house

postiche Superadded; done after the work is
finished, esp. when superfluous, inappropriate,
or in poor taste.

posticum See opisthodomus.

postigo In Spanish architecture and its deriva-
tives, a wicket or peep window or small door set
into a door of much larger size.

post-in-the-ground house Same as poteaux-
en-terre house.

postique Same as postiche.

postis In ancient Roman construction, the jamb
of a door, supporting the lintel.

Post-Medieval architecture A term often
applied to architecture in the 17th century and
early 18th century describing dwellings that
exhibited many of the characteristics of timber-
framed medieval houses, with steeply pitched
roofs, very large fireplaces, large chimney stacks,
and small casement windows.

Post-Modern architecture From the late
1960s on, a term describing architecture that
connotes a break with the canons of Interna-
tional Style modernism. Functionalism and
emphasis on the expression of structure are
rejected in favor of a greater freedom of design,
including Classical historic imagery. This leads
to a new interplay of contemporary forms and
materials with frequent historic allusions, often
ironic, as, for example, in the use of nonsupport-
ing Classical columns and medieval arches.
Post-Modern architecture also accepts the man-
ifestations of commercial mass culture, such as
bright colors, neon lights, and advertising signs.
Also see Neo-Eclectic.

Post-Modernism In architecture, the term
Post-Modernism connotes the break with the
canons of International Style modernism. Func-
tionalism and emphasis on the expression of
structure are rejected in favor of a greater free-
dom of design. There is a new interplay of
contemporary forms and materials, with fre-
quent historic allusions, often ironic, as for
example in the use of non-supporting classic
columns, medieval arches and even port-holes.
Post-Modernism also accepts the manifestations
of commercial mass culture: bright colors, neon
lights, and advertising signs of the Las Vegas
type. Most influential for the formulation of a
post-modernist program were the writings of

Robert Venturi. The A.T.&T building in New
York by Philip Johnson and John Burgee can be
considered one of the earliest major examples of
Post-Modernist architecture.

post-occupancy services 1 . Those services
which are necessary to assist the owner in
occupying a facility under a designated service
form-of-agreement between owner and archi-
tect. 2. The services rendered by the architect
after issuance of the final certificate for pay-
ment under a form-of-agreement.

post office An office or building where letters
and parcels are received and sorted, and from
where they are distributed and dispatched to
various destinations.

post-on-sill house Same as poteaux-sur-solle
house.

post pole A single vertical member which sup-
ports loads.

postscenium, postscaenium 1. In the ancient
theater, the rooms behind the stage where the
actors dressed and where machines were
stored. 2. The back part of the stage of a the-
ater, behind the scenes.

post shore Same as post pole.

posttensioning A method of prestressing rein-
forced concrete in which tendons are tensioned
after the concrete has hardened.

potable water Water which is fit to drink and
satisfies the standards of the appropriate health
authorities.

potato barn A special-purpose barn for the long-
term storage of potatoes; sunk below ground level
to provide a cool temperature the year round.

poteaux-en-terre house In French Vernacu-
lar architecture, a Cajun dwelling of the earliest
settlers, primarily in the Louisiana Territory. To
serve as vertical supports, closely spaced posts
were driven into the ground and the space
between them was filled with a mixture of clay
and Spanish moss or clay and small stones. Com-
pare with poteaux-sur-solle house.

poteaux-sur-solle house In early French Ver-
nacular architecture, a Cajun dwelling similar to a
poteaux-en-terre house but supported by a hewn-
log structural framework that usually rested on
sills, 1 (i.e., heavy horizontal timbers supported by
cypress blocks placed under the sills). The space
between the hewn logs was filled with pierrotage

755

potential transformer

or briquette-entre-poteaux; then plastered and
whitewashed in a manner similar to that of
medieval half-timbering. The houses commonly
had a shingle-covered bonnet or hipped roof. Indi-
vidual rooms were provided access from a porch
that ran across the face of the house.

potential transformer Same as voltage trans-
former.

pot floor A floor of structural clay tile.

pot glass Said of colored glass in which the col-
oring is embedded in the glass itself.

pothead A device used to provide a weather-
tight seal at the end of an electrical cable, serv-
ing as an insulated egress for the conductors ).

pot life 1 . The period of time during which a
thermosetting plastic or rubber composition
remains suitable for its intended use after mix-
ing with a reaction-initiating agent; working
life. 2. The length of time a paint material is
useful after its original package is opened, or
after catalyst or other ingredients are added;
also called usable life, spreadable life.

pot metal 1 . Cast iron of a quality once used for
making cooking pots. 2. An alloy of copper and
lead, once used for plumbing fixtures.

pottery 1 . Any fired clayware which is pro-
duced by a clay worker. 2. The low-fired, porous,
colored body ware, in contrast to white or buff-
colored earthenware.

potting-up 1. The transplanting of a seedling
plant into a flower pot. 2. The transplanting of a
mature plant from the outdoors to a large pot
placed indoors, usually for decorative purposes
or to protect the plant from a harsh climate dur-
ing the winter.

poultry house A place for housing fowl; once
considered essential on most rural houses, farms,
or estates before refrigerators because this pro-
vided a source of fresh eggs and freshly killed
meat; also see dovecote.

pounced Decorated with indentations or per-
forations.

pound-calorie The amount of heat required to
raise one pound of water one degree centigrade.

pour A batch of concrete cast in a single opera-
tion.

pour coat, top mop 1. On a built-up roof, the
top coating of bitumen. 2. The final pouring of

hot bitumen in which the gravel or slag surfac-
ing is embedded.

poured concrete See concrete.

poured floor See polymeric poured floor.

poured joint An electrical joint that is insulated
by means of an insulating medium which is poured
around it and which subsequently solidifies.

pouring rope See asbestos joint runner.

powdered asphalt Hard asphalt which is
crushed or ground to a fine state; softened by
combining it with flux oil.

powder house An isolated storage place for
gunpowder; once found in areas subject to
enemy attack; also called a powder magazine.

powdering Decoration by means of numerous
small figures, usually the same figure often
repeated.

powder molding A technique for producing
objects of varying sizes and shapes by melting
polyethylene powder, usually against the inside
of a mold.

powder post A condition of wood which has
decayed to powder, or has been eaten by worms
which leave holes full of powder.

powder room l.The anteroom of a women's
toilet, in which makeup and clothing are adjusted;
by extension applied to a women's toilet itself. 2.
The small first-floor toilet room in a house.

power The rate at which work is performed,
energy is transformed or transferred, or energy is
consumed; usually expressed in watts or horse-
power.

power-assisted door A door that opens by
means of a mechanism that is activated by an
electric switch; especially useful to those with
physical disabilities and often required by the
Americans with Disabilities Act. Also called a
power-operated door.

power buggy A materials-handling machine,
about the size of a wheelbarrow, driven by a
gasoline-powered engine or electric motor.

power cable An assembly of one or more elec-
tric conductors with one or more of the following
protective coverings: insulation, inner jacket,
protective armor, and outer jacket.

power cart Same as power buggy.

power circuit protector A low- voltage,
fused, nonautomatic circuit breaker; has a
circuit-breaker-type operating mechanism but

756

PP-AC

power buggy

is protected by fuses rather than by a direct-act-
ing or relay-operated tripping device.

power conditioner A packaged unit on an
electric power line which provides clean power;
may contain surge arresters, harmonic filters,
isolation transformers, and voltage regulators.

power consumption The power used multi-
plied by time; measured in kilowatt-hours,
horsepower-hours, etc.

power drill A drill, 1 driven by an electric
motor which transfers power to the chuck when
a trigger-type switch is closed.

power elevator An elevator whose motion is
driven by the application of a mechanical force
other than that supplied by hand or gravity.

power factor In an alternating current, the
ratio of the average power (expressed in watts)
to the apparent power (expressed in volt-
amperes).

power float See rotary float.

powerhouse A building in which electricity or
other form of power is generated.

power level See sound power level.

power of attorney An instrument authoriz-
ing another to act as one's agent. Also see attor-
ney-in-fact.

power-operated scaffold Any form of scaf-
fold that is propelled vertically by the use of
power machinery.

power outage See outage.

power panelboard A panelboard which serves
branch circuits supplying motors and other heavy
power-consuming loads.

power roller A paint roller in which paint is
supplied to the roller under pressure.

power sander A portable, electric hand tool
having a moving abrasive surface; used for smooth-
ing and polishing; also see sanding machine.

power shovel 1 . A power-operated machine
used to excavate and load dirt, rock, or debris by
means of an open-ended bucket at the end of an
arm which is suspended from a boom; cables or
hydraulic rams force the arm (and therefore the
bucket) forward and upward, into the material;
then the bucket is raised and its load is dumped.
2. A machine having a scoop or bucket for dig-
ging up or removing loose material.

power shovel

power take-off On construction equipment,
any device for driving an auxiliary attachment
or tool using the torque or power of the prime
mover's motor or engine.

power transformer In an alternating current
electrical system, a device for transforming the
source of electrical supply from one voltage to

another.

power trowel A mechanical trowel.
power wrench See impact wrench.
poyntel Same as pointel.

pozzolan, pozzolona, pozzuolana A sili-
ceous or siliceous and aluminous material,
which in itself possesses little or no cementi-
tious value but will, in finely divided form and
in the presence of moisture, chemically react
with calcium hydroxide at ordinary tempera-
tures to form compounds possessing cementi-
tious properties.

pozzolan cement Pozzolan interground with
lime; a natural cement used in ancient times.

pozzolanic Of or pertaining to pozzolan.

pozzuolana See pozzolan.

PP-AC Abbr. for "power panel air-conditioning."

757

PPGL

PPGL On drawings, abbr. for "polished plate

glass."
ppm Abbr. for parts per million.

PR On drawings, abbr. for "pair."

practical completion See date of substantial
completion.

praecinctio In the ancient Roman theater, a
walkway between the lower and upper tiers of
seats, running parallel to the rows of seats.

praetorium Same as pretorium.

prairie box A Prairie style house having a
square floor plan, usually having a symmetrical
facade and a room in each of the four corners of
the house, a hipped roof, and occasionally
hipped dormers; somewhat popular in the early
1900s; also called an American four-square
house.

prairie cottage A cottage constructed of air-
dried adobe bricks; built by settlers on the
prairies of the western United States where
stone was scarce, but clay suitable for brick mak-
ing was usually available close to the surface of
the ground. Sand, ashes, and linseed oil were
often added to the clay. After the bricks air-dried
for 10 to 12 days, they were laid with mortar in a
construction that required minimal technical
skill. Battened doors were common. The roof,
usually shingled or thatched, had a large over-
hang to protect the adobe walls against erosion
by rain. Contrast with a Prairie style house.

Prairie School A highly original group of influ-
ential architects in Chicago, closely associated
with the early work of Frank Lloyd Wright
(1867-1959) and, to a lesser extent, with Louis H.
Sullivan (1856-1924) and their followers. The
Prairie School was also influenced by the Arts and
Crafts Movement in England. Many of the early
works created by this school are in the Prairie
style.

Prairie style A style of American domestic
architecture that originated with the Prairie
School, popular primarily in the Midwest from
about 1900 to 1920. A house in this style often
is characterized by: a two-story height with
wings and/or porches of one story, integrated
with its site to provide a low, horizontal
appearance; the central portion of the house
usually higher than the adjacent flanking
wings; traditional building materials; exterior

■U- *jtj _gjyT ^^j^^MMptJUl

i^m

Prairie style

walls commonly of light-colored stucco, light-
colored brick, or concrete block; contrasting
wood trim between stories; a porte cochere
and/or a porch having a roof typically sup-
ported by heavy columns that are either square
in cross-section or have slanted sides; a terrace
and/or balcony; often, Sullivanesque friezes
and/or door surrounds; a broad, low-pitched
roof; eaves with a considerable overhang;
hipped or gabled dormers; a prominent, large,
relatively low rectangular chimney; often, a
series of windows below the roof overhang;
commonly, diamond-shaped window panes set
in lead cames; commonly, one-over-one dou-
ble-hung sashes or tall casement windows,
often grouped in sets of two or three; doors
having windows, often glazed with highly dec-
orative geometric patterns.

prang In Thai architecture of the 13th to 18th
cent. A.D., a sanctuary consisting of a tower-like
main temple with a porch structure.

Pratt truss A truss having parallel chords, verti-
cal members in compression, and diagonal mem-
bers (which slant toward the center) in tension.

PRC Abbr. for "precast reinforced concrete."

PRCST On drawings, abbr. for "precast."

preaction sprinkler system A dry-pipe
sprinkler system which is activated by a smoke-
or heat-sensing device, thereby opening a con-
trol valve and admitting water.

preaching cross A cross erected in the imme-
diate vicinity of a small chapel (on a highway or
in an open place) to mark a place where monks
or others could assemble for religious purposes.
Also see weeping cross.

preaction sprinkler system A fire sprinkler
system using automatic sprinklers (heads)
attached to a piping system; is controlled by a sup-
plemental fire detection system, that is installed
in the same area as the sprinklers; actuation of the
detection system opens a valve which permits

758

predella

CHANNEL

preaching cross at Inverary, Argyllshire, Scotland

water to flow into the piping and to be discharged
from the sprinklers; differs from a deluge sprinkler
system in that automatic sprinklers are used rather
than open sprinklers. There is no water in the pip-
ing under ordinary circumstances.

preassembled lock, mono lock, rigid lock,
unit lock A lock all of whose parts are
assembled as a unit at the factory; requires little
or no disassembly when installed in a rect-
angular notch cut into the door edge.

preboring Drilling a pilot hole.

precast Said of a concrete member that is cast
and cured in other than its final position.

precast concrete pile See precast pile.

precast concrete wall panel A precast con-
crete exterior panel or area separator; may be
load-bearing or non-load-bearing.

precast pile Any reinforced concrete pile
which is not cast in its final position.

precast stone Same as artificial stone.

precinct The grounds immediately surrounding

a cathedral.
precinctio Same as praecinctio.
precipitation At a given location, the total

measurable supply of water received directly as

DOUBLE- TEE

precast concrete (double-tee plank)

rain, snow, hail, or sleet; usually expressed in
inches (millimeters) per day, month, or year.

precipitator See electrostatic precipitator.

precise level An instrument designed specifi-
cally for obtaining precise results by direct level-
ing techniques; essentially the same as an
engineer's level with micrometers and also a prism
arrangement permitting the simultaneous obser-
vation of the rod reading and the level bubble.

precise leveling rod A precision leveling
rod; the graduations are on a ribbon of special
alloy whose precision is little affected by tem-
perature; the ribbon is maintained under con-
stant tension.

precoating See tinning.

Pre-Columbian architecture Architecture
of the indigenous peoples of the Americas prior
to their contact with European civilization.

precompressed zone In prestressed concrete,

that portion of a flexural structural member
which is compressed by prestressing tendons.
preconsolidation The condition of a highly
compressed soil, usually resulting from other
than natural causes, e.g., resulting from vibra-
tion of the soil or the loading of the soil by a
large heap of excavated material.

preconsolidation pressure The greatest effec-
tive pressure to which a soil has been subjected.

precure To cure a glued joint prior to pressing
or clamping.

precut building A manufactured building

composed largely of elements cut to size in a fac-
tory and moved to the erection site for assembly.

predella l.The bottom tier of an altar-piece,
between the principal panel or bas-relief and the
altar itself. 2. The broad platform on which the
altar rests. 3. An altar ledge.

759

preemption

preemption The right to purchase property
before, or in preference to, others.

prefab A factory-built house of standard dimen-
sions; does not include a mobile home or trailer
having less-than-standard dimensions.

PREFAB On drawings, abbr. for "prefabricated."

prefabricate To fabricate components or units
prior to their installation at the site, usually at a
mill or plant away from the site.

prefabricated building See manufactured
building.

prefabricated construction A construction
method relying primarily on the use of standard-
ized manufactured components; consists largely
of assembling these parts rather than fabricating
them at the site.

prefabricated flue A metal vent for fuel-fired
equipment, consisting entirely of factory-made
parts.

prefabricated house A house assembled from
components cut to size at a factory, or assembled
from building modules shipped to the construc-
tion site.

prefabricated joint filler A compressible
material used to fill control joints, expansion
joints, contraction joints, and the like; either
used exposed or as a backing for a joint sealant.

prefabricated masonry panel A wall panel
fabricated of masonry units which are bonded
together at a manufacturing plant and then
transported to the job site as a construction unit,
ready for erection.

prefabricated pipe conduit system Prefab-
ricated mechanical service conduits laid under-
ground or above grade, carrying insulated piping
for one or more utilities.

prefabricated tie A wall tie used in hollow-
wall construction; consists of two heavy parallel
wires which are tied together, at regular inter-
vals, by short wires which are welded to them at
right angles; each of the long parallel wires is
bonded in one of the wall sections.

prefabricated unit A built-up section, form-
ing an individual structural element of a build-
ing (for example, a built-up beam, column,
girder, plank, strut, or truss), which is prefabri-
cated prior to its incorporation into the struc-
ture; usually includes any required means for

erection and connection at the building site to
complete the structural frame.

prefabricated wall Same as demountable par-
tition.

preferred angle 1 . Any angle of pitch of stairs
between 30° and 35°. 2. Any angle of pitch of a
ramp less than 15°.

prefilter In air-conditioning systems, a filter, 1
before the main filter to remove the larger parti-
cles; usually has a lower efficiency than the main
filter and has a low pressure drop characteristic.

prefinished door, prefitted door A door
prefitted to an opening; both faces are factory-
finished to specification and accommodations
are provided for locks and hinges.

preformed asphalt joint filler A premolded
strip of asphalt cement, mixed with a fine sub-
stance such as sawdust or cork; used as a joint filler.

preformed foam Foam produced in a foam
generator prior to introduction of the foam into
a mixer with other ingredients to produce cellu-
lar foam.

preformed joint sealant Same as preformed
sealant.

preformed sealant A sealant preshaped by
the manufacturer so that only a minimum of
field fabrication is required prior to installation.

preheat coil In an air-conditioning system, a
coil used to preheat air which is below freezing
to a temperature somewhat above freezing, in
advance of other processing.

FILTER

PREHEATER REHEATER

BYPASS

preheat coil

preheater See preheat coil.
preheat fluorescent lamp, switch-start flu-
orescent lamp A fluorescent lamp in which

760

pre-shimmed sealant

the electrodes must be preheated in order to
start the arc; the preheating is initiated by either
a manual switch or an automatic-starting switch.

preheating The partial heating of water in a
domestic water system by circulating it through
a first-stage heat exchanger before circulating it
through the final heater.

prehung door An assembly consisting of a
door on its frame, together with all necessary
hardware and trim, ready for installation.

preliminary design Architectural services
performed by an architect in the initial stages of
a project, including the program review, prelim-
inary program evaluation, review of alternative
approaches to design and construction, and
preparation of preliminary design documents.

preliminary drawings Drawings prepared
during the early stages of the design of a project.

preliminary estimate See statement of prob-
able construction costs.

preliminary work Work carried on at the job
site before the start of a construction contract
but usually not part of the actual contract; for
example, pile-driving.

premature stiffening See false set.

premises Land and/or its appurtenances.

premises wiring The interior and exterior
electrical wiring of a building that extends from
(a) the load end of the service drop or service

lateral conductor to (b) the outlets; includes
power, lighting, control, and signal circuit
wiring in addition to all associated hardware, fit-
tings, and wiring devices.

premium-grade lumber The highest grade of
lumber available both in material and workman-
ship; intended for the finest work; compare with
custom-grade lumber and economy-grade lumber.

premixed concrete Sacks of concrete contain-
ing all the necessary ingredients for mixing the
concrete except for water, which must be added.

premixed plaster A mill-mixed plaster.

premolded asphalt panel A panel, usually
made under pressure, with a core of asphalt,
minerals, and fibers, covered on each side by a
layer of asphalt-impregnated felt or fabric,
coated on the outside with hot applied asphalt.

prepacked concrete See preplaced-aggregate
concrete.

prepared roofing See asphalt prepared roofing.

prepayment meter A coin-operated water or
gas meter; dispenses a fixed quantity of fluid after
the money is inserted.

preplaced-aggregate concrete, prepacked
concrete Concrete produced by placing
coarse aggregate in a form and later injecting a
Portland cement-sand grout, usually with ad-
mixtures, to fill the voids.

pre-posttensioning A method of fabricating
prestressed concrete in which some of the ten-
dons are pretensioned and others are postten-
sioned.

prepreg In a reinforced plastic, the reinforcing
material containing or combined with the full
complement of resin before molding.

prequalification of prospective bidders

The process of investigating the qualifications of
prospective bidders on the basis of their compe-
tence, integrity, and responsibility relative to the
contemplated project.

pre-Romanesque architecture The several
regional and transitional styles that evolved
between the fall of the Roman Empire and the
emergence of Romanesque architecture in the
11th century; among them the Lombard, Car-
olingian, and Ottoman architecture.

presbytery, presbyterium The actual sanc-
tuary of a church beyond the choir and occupied
only by the officiating clergy.

prescriptive specification A specification by
name of product, equipment, or system to be
used, as opposed to a specification that is based
on performance criteria.

presence chamber, presence room The

room in which a great personage receives his
guests or those entitled to come before him; a
hall of state.
preservation See building preservation.

preservative l.A product, such as creosote,

used to make wood waterproof or immune
against attack by insects, etc. 2. A protective
coating on a metal surface.

pre-shimmed sealant A sealant (e.g., strip
of resilient plastic or rubber) which has encap-
sulated solids or discrete particles which limit
its deformation within a joint under compres-
sion.

761

pre-shimmed tape sealant

pre- shimmed tape sealant A pre-shimmed
sealant in tape form.

preshrunk 1. Descriptive of concrete which
has been mixed for a short period in a stationary
mixer before being transferred to a transit mixer.
2. Descriptive of grout, mortar, or concrete that
has been mixed 1 to 3 hr before placing to
reduce shrinkage during hardening.

presidio In Spanish architecture and its deriva-
tives, a frontier outpost or fort.

pressed brick Brick that has been subjected to
pressure so as to provide sharp edges and smooth
surfaces before being treated in a kiln.

pressed edge That edge of a footing along
which the greatest soil pressure occurs under
conditions of overturning.

pressed glass Any unit of glass pressed into
shape, such as glass block, pavement light, etc.

pressed-metal ceiling A sheet-metal ceiling
embossed in a decorative pattern; usually coated
with a layer of tin and lead or a coat of paint
primer as a protection against oxidation; much
used on the ceilings of stores after about 1875,
especially during the early part of the 20th
century.

pressed reflector lamp Same as PAR lamp.

pressed steel Steel which has been pressed into
shape between dies to form a building component.

pressure The force per unit area exerted by a
homogeneous liquid or gas on the walls of its
container.

pressure bulb The zone in a loaded soil mass
bounded by an arbitrarily selected isobar of stress.

pressure cell A device for measuring the pres-
sure within a soil mass or the pressure of soil
against a rigid wall.

pressure connector, solderless connector

A device which establishes a connection between
two or more electric conductors, or between one
or more conductors and a terminal, by means of
mechanical pressure and without the use of
solder.

pressure creosoting The forcing of creosote,
under pressure, into timber as a preservative.

pressure drainage A condition in which a
static pressure may be imposed safely on the
entrances of sloping building drains through soil
and waste stacks connected thereto.

pressure connectors

pressure drop The decrease in fluid pressure
between two ends of a duct or pipeline,
between two points in a system, across valves
and fittings, etc., due to frictional losses; in a
water-piping system a drop in fluid pressure
also occurs between two points as a result of
the difference in elevation between the two
points.

pressure forming In plastics, a thermoform-
ing process in which pressure is used to push the
sheet to be formed against the mold surface in
contrast to the use of a vacuum to pull the sheet
flat against the mold.

pressure gauge An instrument for measuring
fluid pressure.

pressure gun Same as caulking gun.
pressure head See static head.
pressure-locked grating A grating in which

the cross bars are locked mechanically to the

bearing bars at their intersections by deforming

or by swaging the metal.
pressure pipe Pipe which is designed to resist a

continuous pressure exerted on it by the medium

which it conveys.

pressure-reducing valve, reducing valve

l.A pressure regulating valve. 2. A valve that
maintains a predetermined pressure by means of
an automatic valve controller.

pressure regulating valve (PRV) A device
used to reduce and maintain the water pressure
automatically with predetermined design param-
eters, for both dynamic flow and static conditions.

pressure regulating valve station, PRV
station An installation of multiple pressure

762

prestressed concrete

regulating valves in a single zone of a water sup-
ply system in a building.

pressure regulator l.In a fire sprinkler sys-
tem, a device that limits water pressure, under
both flow and no-flow conditions, in those por-
tions of the system where it is probable that the
pressure may exceed 1 75 pounds per square inch
(11,400 kPa). 2. A pressure-reducing valve.

pressure-relief damper A relief damper
installed in a system which relieves pressure in
excess of a preset limit.

pressure-relief damper

pressure-relief device A disk which is de-
signed to open or a device which is designed to
rupture automatically in order to relieve pressure
within a system.

pressure relief hatch See smoke and fire vent.

pressure relief valve In a pressure tank for
water storage, a pressure-actuated safety valve that
is designed to open and relieve pressure automati-
cally if the pressure within the tank exceeds the
value for which it was designed to operate safely.

pressure-relieving joint In panel-wall mason-
ry, an open joint left at specified horizontal inter-
vals to allow for expansion and contraction;
commonly below horizontal supporting hangers
at each floor to allow for expansion and contrac-
tion and to prevent the weight of higher courses
from being transmitted to the masonry below.
Such joints are stopped with flexible caulking
compound to exclude moisture.

pressure-sensitive Capable of adhering to a
surface when pressed against it.

pressure-sensitive adhesive A viscoelastic
material which remains permanently tacky in a
solvent-free form; will adhere instantaneously to
most solid surfaces with the application of very
slight pressure.

pressure tank A closed cylindrical steel con-
tainer designed to store water under pressure.

pressure-treated lumber Lumber that has
been impregnated under pressure with a chemi-
cal preservative or fire retardant.

pressure-type vacuum breaker A vacuum
breaker containing an independently operating,
internally-loaded check valve and an indepen-
dently operating air inlet valve on the discharge
side of the check valve.

pressure weather stripping Weather strip-
ping which is designed to provide a seal of con-
stant pressure by means of spring tension.

pressure wire connector A device that estab-
lishes an electrical connection between conduc-
tors (or between a conductor and a device) solely
by mechanical pressure.

pressure zone An area of a building (it may
be an entire floor, several floors, or the entire
building) supplied with water having a
common pressure origin or a common water
supply.

pressurized area Same as pressurized zone.

pressurized escape route In a building, an
escape route that is maintained at a higher air
pressure than its surroundings; in the event of
fire, the higher pressure helps prevent smoke
from spreading into the escape route.

pressurized stairway enclosure A stairway
enclosure whose interior is maintained at a
slightly elevated pressure to minimize smoke
contamination during a fire.

pressurized structure Same as pneumatic
structure.

presteaming period The period of time
between the molding of a concrete product and
the start of the temperature rise in the curing
process.

prestress 1. The stress developed in prestressed
concrete. 2. To apply loads to a structure or to a
structural element for the purpose of beneficially
modifying internal stresses.

prestressed concrete Concrete in which inter-
nal stresses are introduced of such magnitude and

763

prestressed concrete wire

distribution that the tensile stresses resulting from
the service loads are counteracted to a desired
degree; in reinforced concrete the prestress com-
monly is introduced by tensioning the tendons.

prestressed concrete wire Steel wire having
a very high tensile strength, used in prestressed
concrete by embedding it under tension in the
concrete.

prestressed pile A concrete pile which is pre-
stressed or posttensioned in order to eliminate or
reduce cracking during its transportation to the
construction site, during driving, and while in
service.

prestressing Applying a load to a structure,
deforming it so that it will withstand a working
load more effectively or so that it will deflect less.

prestressing cable See tendon.

prestressing steel High-strength steel (in the
form of bars, rods, wires, etc.) which is used to
prestress concrete.

presumptive bearing pressure The verti-
cal bearing pressure which is permitted in the
absence of extensive investigation and testing.

pretensioned concrete Concrete which has
been subjected to pretensioning.

pretensioning A method of prestressing rein-
forced concrete in which the tendons are ten-
sioned before the concrete has hardened.

pretil In Spanish architecture and its deriva-
tives, a parapet, a breast-high wall, or a brick
coping atop a wall.

pretorium In the ancient Roman Empire, the
official residence of a provincial governor; a hall
of justice; a palace.

preventive maintenance Maintenance at

time-fixed intervals; intended to reduce the
probability of failure or lessened performance in
the period up to the next inspection. Also called
scheduled maintenance.

pricking coat, pricked-up coat Same as
scratch coat (i.e., first coat of plaster).

pricking up Scoring a first coat of plaster on lath.

prick post In a wood-framed structure, a sec-
ondary post or side post.

prick punch A pointed steel punch which is
struck with a hammer; used to mark metal or
sheet metal.

prick punch

prie»dieu A small desk before which a person
may kneel when praying.

priest's door The door by which the priest
enters the chancel from the side.

primacord A detonating fuse having a core
contained within a waterproof covering; used to
detonate explosives.

primary air 1. In a water heater, the air which is
fed to the burner to be mixed with gas. 2. The air
which is delivered to any type of air outlet or grille
by a supply duct.

primary battery Two or more primary cells.

primary beam Same as main beam.

primary blasting The blasting operation by
which the original rock formation is dislodged
from its natural location.

primary branch 1. A drain which slopes from
the base of a soil stack or waste stack to its junc-
tion with a building drain. 2. In a building, the
largest single branch of a water-supply line or an
air-supply duct.

STACK STACK

PRIMARY BRANCH

PRIMARY
BRANCH

BUILDING DRAIN

primary branches, 1

primary cell A cell that generates electric cur-
rent by electrochemical means; the discharge of
electric current causes one of the electrodes in
the cell to be consumed; usually a cell cannot be
recharged from an external source of electric
power, although some can be recharged to a lim-
ited extent.

primary circulation areas The areas of a build-
ing that are required for access to its entrances,
corridors, elevators, lobbies, stairs, and toilets.

primary compression failure In reinforced
concrete, failure that is initiated by the crushing
of concrete.

764

principal post

primary consolidation, primary com-
pression, primary time effect The

reduction in volume of a soil mass caused by
the application of a sustained load on the mass;
principally due to the squeezing out of water
from the voids in the mass, accompanied by a
transfer of the load from the soil water to the
soil solids.

primary contract Same as prime contract.

primary distribution feeder A feeder which
operates at the primary voltage supplying a dis-
tribution circuit.

primary entrance The principal entrance to
a building expressly utilized for day-to-day
pedestrian ingress and egress.

primary excavation The excavation of soil

which has not previously been moved.

primary fluid, primary refrigerant The

refrigerant in a refrigeration system which takes
up heat, by evaporation.

primary light source l.A source in which
light is produced directly from a transformation
of energy. 2. The principal, or most obvious,
source of light when several sources of light are
present.

primary member See main member.

primary subcontractor A subcontractor who
performs a significant portion of the work on a
construction project.

primary tension failure In reinforced con-
crete, failure that is induced by plastic deforma-
tion of the steel reinforcing rods.

primary time effect See primary consolidation.

primavera A relatively lightweight, yellowish
white to brown wood of Central and South
America, frequently with ribbon-stripe figures;
used for cabinets, plywood and interior finish.

prime coat, priming coat A first coat with a
primer, 1 .

prime contract A contract between the owner
and contractor for construction of a project or
portion thereof.

prime contractor Any contractor on a project
having a contract directly with the owner.

prime mover l.Any machine that converts
fuel (e.g., diesel oil, gasoline, or natural gas) or
steam into mechanical energy. 2. A powerful
truck, tractor, or the like.

prime professional Any person or firm hav-
ing a contract directly with the owner for profes-
sional services.

primer l.A paint, applied as a first coat,
which serves the function of sealing and filling
on wood, plaster, and masonry; inhibits rust
and improves the adhesion of subsequent coats
of paint on metal surfaces. 2. A thin liquid
bitumen solvent; applied to a roof surface to
absorb dust and to improve the adhesion of
subsequent applications of bitumen. 3. A car-
tridge or container of explosives into which a
detonator or detonating cord is inserted or
attached.

prime standby power source See standby
power generator.

prime window The window to which a storm
window is attached.

priming The application of a primer.

priming coat Same as primer, 1.

princess post In a truss, a vertical post between
the queen post and the wall to supplement the
support of the queen post.

principal 1 . One on whose behalf or in whose
name binding transactions may be entered into
by another, usually called the agent. 2. One for
whose debt or default another (called a "surety")
promises to make good. 3. In professional prac-
tice, any person legally responsible for the activ-
ities of such practice. 4. In a framed structure, a
most important member, such as a truss which
supports the roof.

principal beam The largest or main beam in a
framework.

principal brace l.Same as sway brace. 2. A

brace supporting a principal rafter.

principal elevation The facade or front eleva-
tion of a building.

principal facade The architectural front of a
building, often distinguished from the other faces
by the use of better materials and greater elabora-
tion of architectural or ornamental details; usu-
ally faces a street, but occasionally faces a mews or
court.

principal joist In a timber-framed house, a
large joist that carries much of the floor load.

principal post A corner post in a timber-
framed house.

765

principal purlin

principal purlin In timber-framed construc-
tion, a purlin that is somewhat heavier than a
common purlin; usually runs parallel to the
ridge of the roof about halfway between the
ridge and the top plate. The only purlin on
each side of the roof ridge, it is framed into and
joins the principal rafters, thus providing lat-
eral stability for the entire roof framing system
and support for a number of common rafters.

principal rafter In a timber-framed house, one
of several such rafters that extend from the ridge of
the roof down to the wall plate; somewhat heavier
than a common rafter; often located at a corner
post, story post, or chimney post and framed into a
tie beam. Principal rafters, together with the prin-
cipal purlins, form a roof framing system having
considerable stability. Also called a blade.

principal roof, principal rafter roof A roof
supported by principal rafters.

print 1. A plaster cast of a flat ornament. 2. See
printing.

printing Forming a permanent impression in a
semihardened paint film as a result of pressure
from an object placed on it.

print room In English 18th cent, interiors and
derivatives, a room decorated by affixing prints
to the walls.

priory A religious house governed by a prior or
prioress.

prismatic billet molding A common Nor-
man molding consisting of a series of prisms,
with alternate rows staggered.

prismatic billet molding

prismatic glass Rolled glass %to l A in. (3.2 to
6.4 mm) thick, one face of which consists of par-
allel prisms that refract the transmitted light,
thereby changing the direction of the light rays.

prismatic rustication In Elizabethan architec-
ture, rusticated masonry with diamond-shaped
projections worked on the face of every stone.

prismatic vault A brick vault, 1 constructed of
folded panels; particularly found in central
Europe in the 15 th and 16th centuries.

prism glass Same as prismatic glass.

privacy landscape screen See office land-
scape screen.

privacy latch A latch on a toilet or W.C. door
that provides a mechanically-operated indica-
tion as to whether the space within is occupied.

private area The area, whether within or out-
side a building, which is reserved for the exclu-
sive use of a single family.

private branch exchange (PBX) A private
telephone switching system located on the cus-
tomer's premises, usually serving an organization
(such as a business or government agency). It
switches telephone calls within a building and
also to an outside telephone network.

private residence A separate dwelling (or
separate apartment) occupied only by the mem-
bers of a single family unit.

private sewage disposal system A system
composed of a septic tank with its effluent dis-
charging into: (a) a subsurface absorption field,
(b) one or more seepage pits, or (c) some combi-
nation of (a) and (b) or any other facility per-
mitted by code.

private sewer A sewer privately owned; con-
trolled by public authority only to the extent
provided by law.

private stairway A stairway serving one ten-
ant only and not for general public use.

privy An outhouse which serves as a toilet.

privy chamber Same as presence chamber.

prize house In tobacco-growing states of the
southern United States, a structure that once
housed a press (called a prize) for compacting
cured tobacco leaves.

proaulion In the early Church, and in the
modern Greek Church, the porch or vestibule
of the church; an outer porch before the
narthex.

procathedral A church used as the cathedral
church of a diocese while the proper church
remains unfinished or under repair.

processed glass A glass whose surface has
been altered by ceramic enameling, chipping,
grinding, etching, or sandblasting.

766

program

processed shake A sawn cedar shingle; tex-
tured on one surface to resemble a shake.

procession aisle In a church, the aisle at the
back of the high altar.

processional path A continuation of the
choir aisles behind the high altar in an apsidal
(and sometimes in a square-ended) church.

processional way A monumental roadway
for ritual processions in an ancient city, e.g.,
Babylon.

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ancient Egyptian processional way

procoeton In ancient Greece and Roman
dwellings, an antechamber or room preceding
other rooms or chambers.

Proctor compaction test A test to determine
the optimum moisture content of a soil; the soil is
compacted according to a specified procedure, and
then compacted samples of the soil are weighed.

Proctor penetration needle A needle, 0.05
to 1 sq in. (0.32 to 6.45 sq cm) in area, used with
a spring balance, to measure the resistance of
fine-grained soil to penetration.

Proctor penetration resistance See stan-
dard penetration resistance.

prodigy house One of a number of extrava-
gant houses constructed in England at the begin-
ning of the 17 th century.

prodomos 1. A lobby or vestibule. 2. A pronaos.

producer A manufacturer, processor, or assem-
bler of building materials or equipment.

product data Information certified by a manu-
facturer concerning its products, such as the
product's composition, characteristics, uses,
applications, guarantees, warranties, and condi-
tions under which they should or should not be
used. Also see certification.

product information notes Notes produced
during the design phase of a building that indicate
the architect's preference for certain colors, tex-
tures, and finishes of building products.

production drawings See working drawings.

production phase See construction phase.

production greenhouse A greenhouse for
growing large numbers of plants and flowers on a
production basis or for research, without public
access.

professional adviser An architect engaged by
the owner to direct an authorized design compe-
tition for the selection of an architect.

professional engineer A designation re-
served, usually by law, for a person or organiza-
tion professionally qualified and duly licensed to
perform such engineering services as structural,
mechanical, electrical, sanitary, civil, etc.

professional liability insurance Insurance
designed to insure an architect or engineer
against claims for damages resulting from alleged
professional negligence.

professional practice The practice of one of
the environmental design professions in which
services are rendered within the framework of
recognized professional ethics and standards and
applicable legal requirements.

profile 1 . A guide used to set out brick work or
block work accurately. 2. A soil profile. 3. A ver-
tical section of the surface of the ground, or of
underlying strata, or both, along any fixed line.
On a highway, the profile is usually taken along
the center line. 4. In architectural drawing, the
outline of a vertical section. 5. British term for
batter board.

program A statement prepared by or for an
owner, with or without an architect's assistance,

767

program evaluation and review technique (PERT)

setting forth the conditions and objectives for a
building project including its general purpose
and detailed requirements, such as a complete
listing of the rooms required, their sizes, special
facilities, etc.

program evaluation and review technique
(PERT) A management control technique
applied to building construction; determines
what must be done to complete construction by a
given date. Current construction progress is
monitored on a computer and compared with the
planned schedule so as to provide a management
tool for further planning and decision making.

programme chart (Brit.) Same as project
chart.

progress chart A chart prepared by a contrac-
tor, brought up to date monthly; the principal
trades of the project are tabulated vertically and
the scheduled construction time shown horizon-
tally, from left to right; there are two sets of bars
for each trade, one showing the scheduled start-
ing and completion dates, and the other show-
ing the actual status of the work at the date of
issuance.

progressive kiln, continuous kiln, step-
kiln A dry kiln arranged so that green lumber
enters one end and is dried in progressive steps as
it moves to the opposite end, where it is
removed.

progressive scaling The disintegration, as of
concrete, which at first appears as surface scal-
ing, but gradually progresses deeper.

progress payment A partial payment made
during progress of the work, 1 on account
of work completed and/or materials suitably
stored.

progress schedule A diagram, graph, or other
pictorial or written schedule showing proposed
and actual times of starting and completion of
the various elements of the work.

PROJ On drawings, abbr. for "project."

project l.A construction undertaking, com-
posed of one or more buildings and the site
improvements, planned and executed in a
fixed time period. 2. In an office, a job or a
commission. 3. A planned, large apartment
building or housing complex, usually built at
minimum cost with government funds for low-
income families; also called a housing project.

4. The total construction designed by the archi-
tect, of which the work performed under the
contract documents may be the whole or a part.

project architect The architect who heads
the design team on a construction project and
who usually oversees its work.

project budget The sum established by the
owner as available for the entire project,
including the construction budget, land costs,
equipment costs, financing costs, compensa-
tion for professional services, contingency
allowance, and other similar established or esti-
mated costs.

project chart A schedule indicating when var-
ious aspects of a construction job are to be car-
ried out.

project checklist A list that records the
actions taken by the architect on a construction
project, usually commencing before the agree-
ment with the owner has been signed, continu-
ing through the five phases of the architect's
basic services and supplemental services, and
concluding with postconstruction services.

project closeout The final inspection, submis-
sion of necessary documentation, acceptance,
and concluding payment on a construction proj-
ect, as required by the contract documents.

project cost The total cost of a project includ-
ing professional compensation, land costs, fur-
nishings and equipment, financing and other
charges, as well as the construction cost.

projected window A window having one or
more rotatable sashes (ventilators, 2) which
swing either inward or outward.

projecting belt course A course of masonry,
often elaborate, which projects beyond the face
of the wall.

projecting brick One of a number of bricks
which project beyond the face of a wall, usually
forming a pattern.

projecting header One of many headers, 1
which project beyond the face of a wall to form
a brickwork decorative pattern.

projecting porch A porch that extends beyond
the face of a house, in contrast to an integral
porch set within the main structure of the house.

projecting scaffold A work platform can-
tilevered from the face of a building by means of
brackets secured to the building face.

768

propeller fan

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mmsLJ

projecting bricks

projecting porch

projecting sign A sign attached to, and
extending outward from, a building's face.

projection 1. In masonry, stones which are set
forward of the general wall surface to provide a
rugged or rustic appearance. 2. Any component,
member, or part which juts out from a building.

projection booth A booth, usually at the rear
of an auditorium, for the operation of motion-pic-
ture projectors, slide projectors, or follow spots.

project manager A person selected by an
owner to act in the owner's stead on a project;
the responsibilities of the manager include the
selection and hiring of senior personnel on a
construction project, administrative and techni-
cal responsibilities related to the project, the
making of payments for services rendered, and
related matters.

project manual An assemblage of documents
related to the construction work on a project,
typically including bidding requirements, sam-
ple documents, conditions of the contract, and
specifications.

projector l.A lighting unit which concen-
trates the light within a limited solid angle by

means of mirrors and lenses; provides a high
value of luminous intensity in one direction. 2.
A line dropped perpendicularly from a point to a
plane surface.

project record documents The certificates,
documents, and other pertinent or useful data
related to a building project during its construc-
tion; given to the owner for his or her use prior
to final payment.

project representative The architect's repre-
sentative at the project site who assists in the
administration of the construction contract;
when authorized by the owner, a full-time proj-
ect representative may be employed.

project site See site.

projet A scheme for a project presented by
drawings and/or models as an exercise in the
study of design by architectural students.

promenade A suitable place for walking for
pleasure, as a mall.

promenade tile Same as quarry tile.

promoter Same as catalyst, 1.

prompt box Same as prompter's box.

prompter's box A small box for the
prompter at the center of the footlights, esp. in
an opera house; projects slightly above the
floor of the stage and has an opening facing the
performers.

pronaos The inner portico in front of the naos,
or cella, of a classical temple.

pronaos: r

proof stress A stress, either compression or
tension, which is applied to a material to deter-
mine the magnitude required to produce a spec-
ified permanent deformation usually specified as
a percentage of the original length.

prop A post or shore.

propeller fan An axial-flow fan that operates
against little or no static pressure; used chiefly
for exhaust and circulation purposes. (See illus-
tration p. 770.)

769

properties

propeller fan

properties, props Objects on the stage of a
theater related to a performance, including fur-
niture and decorative elements.

property l.Any asset, real or personal. 2. An
ownership interest.

property damage insurance Part of general
liability insurance covering injury to or destruc-
tion of tangible property, including loss of use
resulting therefrom, but usually not including
property which is in the care, custody, and con-
trol of the insured.

property insurance Insurance on the work
at the site against loss or damage caused by per-
ils of fire, lightning, extended coverage (wind,
hail, explosion, except steam boiler explosion,
riot, civil commotion, aircraft, land vehicles,
and smoke), vandalism and malicious mis-
chief, and additional perils (as otherwise pro-
vided or requested). Also see special hazards
insurance.

property line A recorded boundary of a plot.
property-line wall A wall erected on or along

a property line,
property room A storage room for any object

used on a stage except costumes, lights, and

scenery.
property service drain See sanitary building

drain.

property survey See boundary survey.

proportional dividers A drafting instrument
used in reducing or enlarging drawings; consists
of two legs whose ends are pointed and cross
each other (like the letter X) at a pivot point
whose position can be adjusted; the distance
between the two pointed ends on one side of the

pivot is proportional to the distance between the
pointed ends on the opposite side.

proportional limit The greatest stress which a
material is capable of sustaining without any
deviation from Hooke's law.

proportioning The selection of proportions of
ingredients for mortar or concrete to make the
most economical use of available materials to pro-
duce mortar or concrete of the required properties.

proposal See bid.

proposal form See bid form.

proposal request A request in writing from
the architect to the contractor asking that the
contractor submit the cost of a change that is
proposed.

proprietary specification A specification
which describes a product, material, assembly, or
piece of equipment by its trade name and model
number, rather than by a performance specifica-
tion; sometimes includes the names of one or
more manufacturers who may produce a product
acceptable to the owner and/or his or her design
professional.

propylaeum 1 . The monumental gateway to a
sacred enclosure. 2. (pi., cap. Propylaea) Partic-
ularly, the elaborate gateway to the Acropolis in
Athens.

proportional dividers

Propylaea, 2

propylon In ancient Egyptian architecture, a
monumental gateway, usually between two tow-
ers in outline like truncated pyramids, of which
one or a series stood before the actual entrance
or pylon of most temples or other important
buildings.

proscenium l.In the ancient theater, the
stage before the scene or back wall. 2. The frame
or arch that separates the stage from the seating
areas of an auditorium. 3. The proscenium arch.

770

protected corner

proscenium arch An arch or any equivalent
opening in the proscenium wall through which
the stage is seen by the audience.

proscenium box A box adjacent to the prosce-
nium wall; a stage box.

proscenium door A door in a proscenium
wall through which actors can move on and off
the forestage.

propylon

proscenium, 2 Benaroya Hall (1998), Seattle

proscenium stage A theater stage which is

framed by a proscenium arch.
proscenium theater A theater in which the

stage is framed by a proscenium arch.

proscenium wall A fire-resistive wall which
separates a stage or enclosed platform from the
public or spectators' area of an auditorium or
theater.

proscription The acquisition of title to real
property by one who openly and continuously is
in adverse possession of it for a period sufficiently
long that the statute of limitations bars the pre-
vious owner from reclaiming it (usually 20 years).

proskenion In the ancient Greek theater, a
building before the skene; the earliest high Hel-
lenistic stage; later, the front of the stage.

prospect A scenic view, usually from an ele-
vated position.

prospect tower Same as lookout tower.

prostas l.In ancient Greek architecture, a
vestibule or antechamber. 2. Same as prostasis, 1.

prostasis 1. The portion of the front of a classi-
cal temple in antis which lies between the antae.
2. A pronaos before a cella.

prostoon Same as portico.

prostyle Having a portico of columns at the
front of a building only.

prostyle temple shown in plan

protected area An area within a building
that meets the fire protection requirements
specified by code and provides a means of
escape to the exterior of the building in case of
emergency.

protected construction In fire-protection sys-
tems, all structural members that are constructed,
chemically treated, covered, or protected so that
the individual components, or combinations of
such units, meet the specified values of fire-
resistance ratings for the application.

protected corner The corner of a concrete
slab provided with a means of transferring at
least 20% of the load from that corner to the
corner of an adjacent slab, either by mechanical
means or by aggregate interlock.

771

protected equipment

protected equipment Electrical equipment
(e.g., a motor or transformer) on the load side of
a circuit breaker.

protected escape route A safety passageway
within a building to be used in case of emergency.
See accessible route.

protected membrane roof Same as inverted
roof.

protected metal sheeting Sheet metal which
is coated with a layer of bitumen or other material
to protect it from corrosion.

protected noncombustible construction

Noncombustible construction in which bearing
walls (or bearing portions of walls), exterior or
interior, have minimum fire-endurance ratings
of 2 hr and are stable under fire conditions; roofs
and floors, and their supports, have 1-hr fire-
endurance ratings; stairways and other openings
through floors are enclosed with partitions hav-
ing 1-hr fire-endurance ratings.

protected opening In a wall or partition, an
opening which is fitted with a door, window, or
shutter having a fire -endurance rating appropri-
ate to the use of the wall.

protected ordinary construction Construc-
tion in which roof and floors and their supports
have 1-hr fire endurance, and stairways and other
openings through floors are enclosed with parti-
tions having 1 -hr fire endurance, and which meets
all the requirements of ordinary construction.

protected premise See fire-protected premise.
protected stair See fire tower.

protected shaft Any type of shaft or stairwell
that is enclosed within fire-rated walls, doors, or
other openings.

protected waste pipe A waste pipe from a
plumbing fixture which is not directly connected
to a drain, soil pipe, vent pipe, or waste pipe.

protected wood-frame construction Con-
struction meeting all the requirements of wood
frame construction, and in which roof and floors
and their supports have 1-hr fire endurance, and
stairways and other openings through floors are
enclosed with partitions having 1-hr fire
endurance.

protection See building protection.

protection screen Similar to a detention
screen except that the screen mesh is not put

in tension and the construction may be somewhat
lighter; usually used with psychiatric windows.

protective coating 1. Same as sealer. 2. A
hard, noncorrosive coating on the surface of a
material; for example, a metallic coating that is
anodized, galvanized, or sherardized.

protective covenant l.An agreement, in
writing, which restricts the use of real property.
2. A restriction, which affects the use of real
property, that appears in a legal document con-
veying title to the property.

protective ground An electrical connection
or connections to an approved ground for estab-
lishing and maintaining a common potential on
conductors connected to it.

protective lighting Lighting which is in-
tended to facilitate the nighttime policing of
industrial properties (or the like).

protective membrane A surface material
that meets code requirements for an outer layer
of a fire-resistive assembly containing concealed
spaces.

protectory An institution for care and educa-
tion of children who are delinquent or homeless.

prothesis In a Greek church, a chapel beside the
sanctuary, usually on the north side of the bema.

prothyron In ancient Greece, a porch or
vestibule in front of the door of a house.

proto-Doric Of a style apparently introductory
to the Doric style.

proto-Ionic Of a style apparently introductory
to the Ionic style.

protome In classical architecture and deriva-
tives, a projecting half figure, animal or human,
used in a decorative scheme.

protomic capital A capital decorated with
projecting half figures, animal or human or some
combination thereof.

protractor An instrument graduated in angular
degrees for measuring or laying out angles.

proximity switch A sensor and associated
equipment which is actuated by the presence of
nearby objects.

Prussian blue 1 . A class of deep blue pigments
of ferric -ferrocyanides; tends to fade in light
tints; reactive with alkalies; ferrocyanide blue.
2. Any color produced with Prussian blue, e.g.,
Chinese blue.

PRV See pressure regulating valve.

772

psf

pseudisodomum

proto-Doric

pseudodipteral

proto-Ionic capital

pry bar A heavy steel bar, pointed at one end
and shaped like a chisel at the other end; used
for prying.

prytaneum A public hall in ancient Greek
states and cities where public officials received
and entertained distinguished guests, honored
citizens of high public merit, etc.

p.S.e. Abbr. for "planed and square-edged."

pseudisodomum In Greek or Roman masonry,
ashlar of regular cut stone in which the heights
of the courses are not uniform.

pseudodipteral In classical architecture , having
an arrangement of columns similar to the
dipteral, but with the essential difference of the
omission of the inner row, thus leaving a wide
passage around the cella.

pseudoheader Same as clipped header.

pseudoperipteral Describing a classical tem-
ple or other building having columns all the way
around, those on the flanks and rear being
engaged, not freestanding.

pseudoperipteral

pseudoprostyle In Classical architecture,
same as prostyle but without a pronaos, the
columns of the portico being set less than the
width of an intercolumniation from the front
wall, or being actually engaged in it.

pseudothyrum A secret door, providing ingress
and egress to a premise without being observed.

psf Abbr. for "pounds per square foot."

773

psi

psi Abbr. for "pounds per square inch."

psia Abbr. for "pounds per square inch absolute."

psig Abbr. for "pounds per square inch gauge
(pressure)."

p.S.j. Abbr. for "planed and square -jointed."

psychiatric window A corrosion-resistant
window of a heavy-duty awning type with inte-
rior protection screens, designed for use in men-
tal or psychiatric institutions; it is free of parts
that can be removed by the patient and has a sill
which can be cleaned easily.

psychrograph A self-recording psychrometer,
providing simultaneous readings of dry-bulb and
wet-bulb thermometers.

psychrometer An instrument used to measure
humidity in the atmosphere from two thermome-
ters which are similar except that the bulb of one
is kept wet, the bulb of the other being dry.

psychrometric chart A chart showing the
relationship between dewpoint temperature,
drybulb temperature, wet bulb temperature,
humidity ratio, and relative humidity.

psychrometry The study of moist air.

PT 1. On drawings, abbr. for "part." 2. On draw-
ings, abbr. for "point."

pteroma In Classical architecture, the enclosed
space of a portico, peristyle, or stoa, generally
behind a screen of columns.

pteron l.In a Classical temple, the passage-
way between the walls of the cella and the
columns of the peristyle. 2. The side of a Classi-
cal temple or the row of columns along one side
of the temple.

p.t.g. Abbr. for "planed, tongued, and grooved."
PTN On drawings, abbr. for partition.
P-trap A P-shaped trap forming a water seal in
a waste or soil pipe; esp. used for sinks and lava-
tories.

P-trap

public-address system Same as sound-ampli-
fication system.

public area Any area which is free and open to
the general public at all times.

public conveniences Facilities for public use,
such as drinking fountains, restrooms, tele-
phones, and internet connections.

public corridor A corridor or enclosed pas-
sageway connecting a room or suite with a stair-
way, fire tower, or other designated exit, but
intended to serve only the occupants of the floor
on which it is located.

public garage Garage for temporary parking or
storage of motor vehicles. Usually excludes
repair and maintenance of such vehicles.

public hall A hall, corridor, or passageway
within a building but outside all apartments or
suites of private rooms.

public house Same as tavern.

public housing Low-cost housing, owned,
sponsored, or administered by a municipal or
other governmental agency.

public liability insurance Insurance covering
liability of the insured for negligent acts resulting
in bodily injury, disease, or death of others than
employees of the insured, and/or property damage.

public nuisance See nuisance.

public sewer A common sewer directly con-
trolled by the public authority.

public space 1 . An area within a building to
which there is free access by the public, such as a
foyer or lobby. 2. In some codes, an area or piece
of land legally designated for public use.

public system A water or sewerage system
which is owned and operated by a local govern-
mental authority or by a local utility company
controlled by a governmental authority.

public-use area Rooms or spaces that are
available to the general public.

public use facilities Internal or external rooms
or spaces in a building that are made available for
use by the general public.

public utility A public service such as water,
gas, electricity, telephone, sewers, etc.

public water main A water-supply pipe for
public use, controlled by public authority.

public way Any parcel of land unobstructed
from the ground to the sky, appropriated for the

774

pull-chain operator

free passage of the general public; a minimum
width usually is specified by code.
pudding stone A composite rock containing
rounded pebbles or gravel embedded in a
siliceous matrix; see cyclopean concrete.

puddle To compact loose soil by first soaking it
and then permitting it to dry.

puddle, clay puddle, puddling Clay to
which a little water has been added and which
then has been tempered, to make it homoge-
neous and to increase its plasticity; used to pre-
vent the passage of water.

puddled adobe construction A primitive
wall construction once used in what is now the
American Southwest; built up of successive
layers of an adobe mixture containing enough
water so that it could be poured. The first layer
was poured directly on the ground and allowed
to dry before the next layer was poured on top
of it; successive layers were built up until the
wall reached its full height. Such walls eroded
easily.

puddled earth A soil composed largely of clay
and silt mixed with water; used to make adobe

bricks.

puddle weld A type of plug weld for joining
two sheets of light-gauge material; a hole, burned
in the upper sheet, is filled with a puddle of weld
metal to fuse the upper sheet to the lower.

puddling 1. Inducing compaction in mortar
or concrete by the use of a tamping rod. 2. See
puddle.

pueblo Communal dwelling, usually of stone or
adobe, built by the Pueblo Indians of southwest-
ern US; built in excavated hollows in the faces
of cliffs or on the plains, valleys, or mesas. Usu-
ally entered by means of ladders.

pueblo architecture Communal housing, as
much as five stories high, containing a large
number of individual family units, built by unre-
lated tribes of New Mexico and Arizona known
as "Pueblo Indians." Buildings are constructed of
adobe or a combination of adobe and stone and
have massive exterior walls coated with an
adobe plaster; windows of small size; stepped-
back roof lines; flat roofs supported by roof
beams; interior walls finished with adobe plaster.
Entry to the rooms through a hatchway in the
roof, reached by a ladder.

Pueblo Revival, Pueblo style In the south-
western United States, primarily from about 1910
to 1940, an architectural mode intended to sug-
gest pueblo architecture; usually includes a mix-
ture of Spanish Colonial Revival and Mission
Revival. Such buildings are usually characterized
by: earth-colored stucco walls that provide a low-
profile, adobe-like appearance; rounded corners at
wall intersections; occasionally, battered walls;
brick flooring on the porches and terraces;
stepped-back roof lines in imitation of pueblo
architecture; parapeted flat roofs drained by water-
spouts; rows of wood beams protruding through
the exterior walls, providing structural support for
the roof; casement windows, usually recessed, with
roughly hewn lintels; and battened doors.

puff pipe A short vent pipe on the outlet side
of a trap, to prevent siphonage.

pugging Heavy loose material, such as ashes or
sand, placed as a filler between the joists in floor-
ceiling assemblies; formerly used to improve the
sound insulation between the rooms above and
below the floor.

pugging boards The boards on which pugging
is suspended.

pug mill A machine for mixing and tempering
clay.

pug-mill brick Same as adobe quemado.

pull A handle for opening a door, window, drawer,
etc.

pull box In electric wiring, a box (with a
removable cover) that is inserted in one or more
runs of raceway to facilitate the pulling of con-
ductors through the raceway.

pull-chain operator A chain used to control
the amount of opening of a device such as a
damper, 1 .

pull-chain operator

775

pulldown handle

pulldown handle A pull on the upper sash of
a double-hung window; fixed to the bottom rail.

pulley 1. A wheel having a grooved rim for car-
rying a rope or other line and turning in a frame;
a pulley sheave. 2. A pulley block containing
one or more pulley sheaves.

pulley block A frame or case containing one
or more pulley sheaves; a block, 6.

OUTER STRAP -, V

— PEA

— INNER STRAP

SWALLOW

r^~j/- SMELL

i CHEEK

* FACE

SHEAVE —

BECKET

pulley

block

pulley mortise See chase mortise.

pulley sheave The grooved roller over which
a cord or rope runs in a pulley block.

pulley stile, hanging stile, sash run, win-
dow stile The upright of a window frame in
which the sash pulleys are installed and along
which the sash slides.

(■:■/,:':

pulley stile

pull hardware A fixed handle or grip used to
pull a door open.

pulling In painting, the resistance to movement
while brushing, resulting from high viscosity of
the paint.

pulling over In wood finishing, the smooth-
ing of a nitrocellulose lacquer by rubbing with a
solvent-soaked cloth.

pulling tension The amount of pull placed on
a cable during its installation.

pulling up The softening of a previous coat of
paint as the next coat is applied.

pull scraper A hand scraper consisting of a
steel blade at right angles to the handle; esp.
used for smoothing wood or for removing thick
finishes.

pull shovel Same as backhoe.

pull switch Same as chain-pull switch.

pulpboard A solid board usually composed of
wood pulp. Also see fiberboard.

pulpit An elevated enclosed stand in a church
in which the preacher stands.

pulpit

pulpitum 1 . In a Roman theater, the part of the
stage adjacent to the orchestra; corresponds to
the logeion of a Greek theater. 2. The tribune, 1

of an orator.

776

purchase money mortgage

pulsation In a furnace, the panting of the
flames; an indication of rapid, cyclical changes
of pressure in the furnace.

pulverised-fuel ash British term for fly ash.

pulvinarium A room in an ancient Roman
temple in which was set out the couch (pulivar)
for the gods at a special religious feast.

pulvinated, pillowed Cushion-shaped, bulging
out, as in the convex profile of the frieze in some
Ionic orders.

pulvinus 1. The baluster at the side of an Ionic
capital. 2. An impost block, a dosseret.

pulvinus, 1

pumice Lava having a highly porous, loose,
spongy, or cellular structure; of relatively high
silica content; used in powdered form as an abra-
sive in polishing, etc.

pumice concrete A lightweight concrete that
has pumice as the coarse aggregate and provides
relatively good thermal insulation.

pumice stone A solid block of pumice; used to
polish or rub painted or varnished surfaces.

pumicite Naturally occurring, finely divided
pumice.

pump A device or machine that compresses
and/or transports fluids, usually by pressure or
suction, or both; may be used to remove water
from a construction site or to convey water from
one elevation to another. See water pump.

pumped concrete Any concrete which is trans-
ported through a hose or pipe by means of a pump.

pumping The displacement and ejection of
water and suspended fine particles at joints,
cracks, and edges.

pumpkin dome Same as melon dome.

punch l.A small sharply pointed metal tool
which is struck with a hammer and used for cen-
tering, marking, or starting holes. 2. A steel
driving tool with a sharpened edge, used to cut
holes in sheet metal.

punch list A checklist of all items on a con-
struction project that are unfinished or incom-
plete, have not been done at all, require
replacement or repair, or require additional
work to achieve an acceptable level of work-
manship. Such a list is often established as a
result of periodic inspections at the job site
during construction and may be included in
field reports. All items must be corrected by the
contractor in a timely fashion so that the fin-
ished construction job conforms to the contract
documents.

punched louver See pierced louver.

punch out In a steel web, 1 , a hole that permits
the passage of an electrical conduit or pipe.

punched work Same as broached work. Also
see broach, 2.

puncheon 1. A short, upright piece of timber in
framing; a short post; an intermediate stud. 2. A
split log or heavy slab with the face smoothed. 3. A
short post used as a spacing support in temporary
timbering around an excavation.

punching shear l.The shear stress calcu-
lated by dividing the load on a column by the
product of its perimeter and the thickness of
the base or cap, or by the product of the
perimeter taken at one-half the slab thickness
away from the column and the thickness of the
base or cap. 2. The failure of a base when a
heavily loaded column punches a hole through
it. 3. The punching of a hole through a base by
a heavily loaded column as a result of failure of
the base.

punkah A type of fan (used in Asia, esp. in
India) in the form of a swinging screen; consists
of cloth stretched on a rectangular frame, hung
from the ceiling and kept in motion by a cord
pulled by a servant.

punning A form of light ramming.

pura In Bali, a terraced sanctuary consisting of
three courts enclosed by walls, connected by
richly decorated gates.

Purbeck marble A gray, hard limestone (not
actually a marble) containing many small shells;
takes a very high polish; used in many Gothic
cathedrals in England.

purchase money mortgage A mortgage that
secures a loan the proceeds of which are used to

777

purchaser

finance the purchase of property. Colloquially,
the term generally is employed only to denote a
mortgage taken by the seller of property to secure
later payment to him of the unpaid portion of the
purchase price.

purchaser One who buys or contracts to buy
real property. Also see vendor.

pure tone Sound waves in which only a single
frequency is present; the wave form is that of a
sine wave.

purfle To edge ornamentally, as if with elabo-
rate needlework or lacework.

purge To evacuate air or gas from a duct line,
pipeline, container, space, or furnace; e.g., to
blow out gas from a refrigerant-containing
vessel.

purge valve See air purge valve.

purging l.The process of voiding a pipe of
fuel gas and replacing it with air. 2. The
process of replacing the air in a gas pipeline with
fuel gas.

purlin, purline A piece of timber laid horizon-
tally on the principal rafters of a roof to support
the common rafters on which the roof covering is
laid. Compare with subpurlin; also see common
purlin, principal purlin, ridge purlin, and through
purlin.

PURLINS

purlins

purlin cleat A fastener used to secure a purlin

to its support.
purlin plate In a curb roof, a purlin which is

located at the curb and which supports the ends

of the upper rafters.
purlin post One of the struts which support a

purlin to prevent it from sagging.
purlin roof A roof construction in which

purlins are laid between the principal rafters;

they support the boards that run between the
ridge and eaves of the roof.

purpleheart, purple wood The heartwood
of any of several leguminous South American
trees; hard, durable, fine-grained wood which is
brown in color but turns purple on exposure; esp.
used for inlays and veneer.

purpose-made brick A specially shaped brick.

push bar A heavy bar fixed across a glazed door
or horizontally pivoted window sash; used to
open or close the door, while providing protec-
tion for the glass.

push button A device in an electric circuit
consisting of a button that must be pressed to
activate or disconnect the circuit.

push drill A small, slender hand drill which is
operated by pushing it; a spiral ratchet rotates
the bit.

push hardware A fixed bar or plate used to
push a door open.

push joint Same as shoved joint.

push-on joint A joint having an elastomeric
gasket, 2 that is compressed in the annular space
between a bell end (or a socket) and a spigot-
end of a pipe.

push plate, finger plate, hand plate A

plate applied to the lock stile of a door to protect
it against soiling and wear.

push-pull rule A flexible steel rule which coils
into a case when not in use.

puteus In ancient Roman construction, an
opening or manhole in an aqueduct.

puteus

778

pylon

putlog In bricklaying, one of a number of short
pieces of timber on which the planks forming
the floor of a scaffold are laid, one end resting on
the ledger of the scaffold and the other in a put-
log hole.

secure and seal panes of glass in window frames;
also called painter's putty. 2. In plastering, a fine
cement consisting of lump lime slaked with
water; lime putty. Now, other compounds, pre-
mixed or in powdered form to be combined with
water, are widely used.
putty coat In plastering, the smooth trowel fin-
ish coat, composed of lime putty and gauging
plaster.

putty knife A knife with a broad flexible blade
used for laying on putty.

putty knife

putlogs shown in putlog holes: b

putlog hole A hole left in a masonry or con-
crete wall to provide support for a horizontal
framing member of scaffolding, and filled to
match the wall after the scaffolding has been
removed.

putti Plural of putto.

putto In Renaissance architecture and deriva-
tives, a decorative sculpture or painting repre-
senting a chubby, usually naked infant.

putto

putty 1. A heavy paste composed of pigment,
such as whiting, mixed with linseed oil; used to
fill holes and cracks in wood prior to painting to

puzzolano Same as pozzolan.

PVA See polyvinyl acetate.

PVC 1. Pigment volume concentration; the per-
centage of pigment by volume in the total volume
of a paint film. 2. Abbr. for polyvinyl chloride.

PWA Moderne An architectural style that
combined elements of Art Deco, Streamline
Moderne, and the Beaux-Arts style; applied in
the design of many large public buildings, civic
centers, theaters, and other buildings con-
structed between 1933 and 1944 by the Public
Works Administration (PWA), an agency of the
US Government created during the Great
Depression.

pycnostyle See intercolumniation.

pylon 1. Monumental gateway to an Egyptian
temple, consisting of a pair of tower structures
with slanting walls flanking the entrance por-
tal. 2. In modern usage, a tower-like structure,
as the steel supports for electrical high-tension

pylon, 1

779

pyramid

lines. 3. In a theater, a movable tower (usually
part of a set) for carrying lights.

pyramid A massive funerary structure of stone
or brick with a square base and four sloping
triangular sides meeting at the apex; used
mainly in ancient Egypt. In Central America
stepped pyramids formed the bases of temples;
in India some temples had the shape of trun-
cated pyramids.

pyramidal hipped roof Same as pavilion
roof, 1 .

pyramidal house A one- or two-story house
having a pyramidal roof.

pyramidal light A skylight having the shape
of a polygon, and in which the glazing slopes to
a point.

pyramidal roof A hipped roof that usually has
four or six sloping surfaces, terminating in a peak.

pyramidion A small pyramid, such as the cap
of an obelisk.

pyramid roof A roof which has four slopes ter-
minating at a peak.

pyramid roof

pyriform Same as periform.

pyriform profile

pyrometer An instrument for measuring high
temperatures.

780

qala'a See kal'a.
qasr See kasr.
qibla See kiblah.

QR On drawings, abbr. for quarter round.
qt Abbr. for "quart."

QTR 1. Abbr. for "quarry-tile roof." 2. On draw-
ings, abbr. for quarter.

QUAD. On drawings, abbr. for quadrangle.

quadra 1. A square frame or border enclosing a
bas-relief. 2. The plinth of a podium. 3. Any
small molding of plain or square section, as one
of the fillets above or below the scotia of an
Ionic base.

quadrangle, quad 1. A rectangular courtyard
or grassy area enclosed by buildings or a building.
Most often used in connection with academic or
civic building groupings. 2. Buildings forming a
quadrangle.

quadrant l.An angle-measuring instrument
used for measuring elevations. 2. A quarter-round
molding. 3. A device for fastening together the
upper and lower leaves of a Dutch door. 4. A
quadrant stay.

quadrant arch ring A quarter-circle brace
that carries thrusts from a vault to external but-
tresses.

quadrant molding A convex molding, the
profile of which is one-quarter of a circle. Also
called a quad molding.

quadratura In Baroque interiors and deriva-
tives, painted architecture, often continuing the
three-dimensional trim, executed by specialists
in calculated perspective.

quadrel A square brick, tile, or stone; a quarrel.

quadrifores ianuae Ancient Roman doors
with hinged leaves like shutters, with two leaves
on each side.

quadriga In classical ornamentation and deriv-
atives, the representation of a chariot drawn by

four horses, i.e., a royal or divine accouterment.
Also see triga, biga.

quadripartite Divided by the system of con-
struction employed, into four compartments, as
a vault.

quadripartite vault A groined vault over a
rectangular area, the area defined by ribs on each
side and divided into four parts by intersecting
diagonals.

quadripartite vault

quadriporticus An atrium which is nearly
square and surrounded by colonnaded porticoes.

quadrivalve One of a set of four folds or leaves
forming a door.

quaggy timber Defective wood with numer-
ous shakes. Also see ring shake, starshake, heart
shake.

Quaker plan In the late 17 th and early 18th
centuries, the plan of a three-room stone or
brick house found primarily in Pennsylvania;
typically had one large room with a fireplace in
one corner and an exterior chimney, and two

781

quaking concrete

small rooms along side it, one serving as a
vestibule and the other as a bedroom. Also see
Penn plan.

quaking concrete A concrete of medium
consistency suitable for massive construction,
such as heavy walls and abutments; shakes likes
jelly when rammed in the plastic state.

QUAL On drawings, abbr. for "quality."

qualification test The evaluation of a product
(new, existing, or modified) to determine its
acceptability for a given job or function or to
determine if it conforms to requirements of an
applicable specification.

quality assurance The inspection, testing, and
other relevant actions taken (often by an owner
or his representative) to ensure that the desired
level of quality is in accordance with the applica-
ble standards or specifications for the product or
work.

quality control The inspection, analysis, and
other relevant actions taken to provide control
over what is being done, manufactured, or fabri-
cated, so that a desirable level of quality is
achieved and maintained.

quality of steam The dryness of saturated
steam expressed as a percentage of perfect dry-
ness.

quantity distance tables Same as American
table of distances.

quantity survey A detailed analysis and list-
ing of all items of material and equipment neces-
sary to construct a project. Also called a takeoff.

quantity surveyor A term, especially used in
Britain, for an oversight role for which there is
no direct equivalent in the US. Primarily, the
quantity surveyor checks the drawings; measures
the quantities of work to be done and establishes
their costs; establishes general requirements;
prepares bills of quantities and other bidding and
contract documents; arranges for bids and their
review; advises on the selection of contractors;
advises, negotiates with, and settles with con-
tractors on the costs of change orders; checks
applications for payment; and settles construc-
tion accounts.

quarrel A small pane of glass, usually diamond-
shaped or square-shaped and set diagonally;
framed and held in place by slender, grooved
strips of lead (cames).

quarrels

quarry 1 . An open excavation at the earth's
surface from which building stone is extracted.
2. Same as quarry glass.

quarry-faced Descriptive of the freshly split
face of ashlar, as it comes from the quarry,
squared off only for the joints; usually used in
massive masonry work.

quarry-faced masonry

quarry glass A small, square piece of glass; usu-
ally set diagonally.

quarry run Building stone as it is supplied from
the quarry, unselected for color and texture.

quarry sap The natural moisture in stone as it
comes from the quarry ledge; varies in amount
with the porosity.

quarrystone bond In masonry, an arrange-
ment of stones in an uncoursed rubble wall.

quarry tile, promenade tile Unglazed ceramic
tile, machine-made by the extrusion process from
natural clay or shales; sometimes used for factory
floors.

quarter 1 . A small timber used as an upright
stud in partitions to which the laths are nailed.
2. A square panel.

quarter bend A 90° change in direction, as in
piping.

quarter-cleft Same as quarter-sawn.

782

quartz glass

quarter closer, quarter closure A brick

which has been cut to one-quarter of its normal
length but is of normal thickness and width;
used to complete a course or to space normal-
sized bricks.

quartering house A subsidiary building that
provided housing for servants in the 17 th cen-
tury; usually near or adjoining a principal struc-
ture in the mid- Atlantic area of America.

quarter landing Same as quarterpace.

quarterpace, quarterpace landing, quar-
ter-space landing A stair landing, often
square in plan, between two flights which make
a right-angled (90°) turn.

quarterpace stair A stair having a quarter-
turn. Compare with halfpace stair.

quarter panel A quarter, 2.

quarter round A convex molding the profile
of which is exactly or nearly a quarter of a circle.
An edge or corner when rounded, as in tile or
plaster work, is called a bullnose.

quarter closer

quarter round

quarter-cut, radial-cut Said of veneer which
has growth rings at right angles (or nearly at
right angles) to the face of the veneer.

quartered Same as quartersawn.

quartered partition A partition formed with
quarters, 2.

quarter-girth rule A method sometimes used
to compute the volume of wood in a log.

quarter grain The grain of quarter-sawn wood.

quarter-hollow molding A concave mold-
ing; same as cavetto.

quarter house In French Louisiana in the
1 8th century, the dwelling of a laborer on a sugar
plantation.

quartering l.A method of obtaining a repre-
sentative sample by dividing a circular pile of a
larger quantity into four equal parts and discard-
ing opposite quarters, continuing the process
until the desired size of sample is obtained. 2.
Studs in a building wall. 3. A small scantling.

quarter-round light A window, often one of a
pair, that has the shape of one-quarter of a com-
plete circle.

quartersawn, rift-sawn Descriptive of lum-
ber sawn so that the growth rings intersect the
wide face at an angle of 45° or greater. Also see
edge-grained. (See illustration p . 784.)

quarter section A square tract of land that is
one-half mile on each side.

quarter-space landing See quarterpace.

quarter-turn Descriptive of a stair which, in its
progress from top to bottom, turns 90°.

quarter-turn stair Same as quarterpace stair.

quatrefoil column A column whose cross-
section is a quatrefoil.

quartz The most abundant form of mineral sil-
ica; very hard, will scratch glass.

quartz glass, silica glass Glass consisting
entirely of pure, or nearly pure, amorphous silica;

783

quartz-halogen lamp

OJAftTEfl g

quartersawn

has the highest heat resistance and ultraviolet
transmittance of all glasses.

quartz-halogen lamp A lamp having a
tungsten filament in a quartz envelope; quartz
is used instead of glass to permit higher temper-
atures, higher currents, and therefore greater
light output.

quartz-iodine lamp Obsolete term for a tung-
sten-halogen lamp.

quartzite A variety of sandstone composed
largely of granular quartz which is cemented by
silica forming a homogeneous mass of very high
tensile and crushing strengths; esp. used as a
building stone, as gravel in road construction,
and as an aggregate in concrete.

quartzitic sandstone A type of sandstone in
which most of the grains are quartz and the
cementing material is silica; intermediate
between normal sandstone and quartzite.

quatrefoil A four-lobed pattern divided by
cusps; also see foil.

Quattrocento architecture Renaissance ar-
chitecture of the 15 th cent, in Italy.

quatrefoil

Queen Anne arch An arch over the triple
opening of the so-called Venetian or Palladian
window, flat over the narrow side lights, round
over the larger central opening.

«r

Queen Anne arch

Queen Anne sash A window having an
ornate upper sash and a plain lower sash.

Queen Anne style I.English architecture
during the reign of Queen Anne, from 1702 to
1714; primarily country houses and many houses
in the suburbs of London, often of red brick.
Characterized by a dignified simplicity and mod-
erateness in scale; avoidance of the appearance
of massiveness; hipped roofs hidden behind
parapets; sash windows. 2. An eclectic style of
domestic architecture primarily of the 1870s and
1880s in England and the United States; mis-
named after Queen Anne; actually based on
country-house and cottage Elizabethan architec-
ture. A blending of Tudor Gothic, English
Renaissance, Flemish, (and in the United States
on Colonial elements), houses in this style usu-
ally are characterized by an asymmetrical facade
with emphasis on verticality; often, a front-
facing gable; commonly, timber- framed and
irregular in plan and elevation; decorative
trusses, bracketed posts, gingerbread in the form
of spindlework, finials, and cast-iron cresting;
textured shingles, masonry with variations in
wall surface treatment and color; carved orna-
mentation, and patterned horizontal siding;
contrasting wall materials used in combination
with the various stories decorated differently;

784

quick condition

home in Queen Anne style, 2

one or more conspicuous porches often set
within the main structure of the house; typically,
an irregularly shaped, steeply pitched roof, orna-
mented gables and ridges, overhanging eaves,
bargeboards, second-story projections, various-
shaped ornamental dormers, cresting, finials,
pendants, and/or pinnacles; shingles laid in dec-
orative patterns; tall ornamented chimneys; fre-
quently, a tower; a paneled main entry door
typically located off the central axis of the
facade. Occasionally called Victorian Queen
Anne style to avoid confusion with the 18th-
century Queen Anne style, 1 from which it dif-
fers markedly.

queen bolt Same as queen rod.

queen closer A brick which has been cut in
half along its length; it is of normal thickness but
half normal width; used to complete a course or
to space normal-sized bricks.

queen closure Same as queen closer.

queen post One of the two vertical supports in
a queen-post truss.

queen-post roof A roof supported by two
queen posts.

queen closer

queen-post roof

queen-post truss, queen truss A roof truss
having two vertical posts between the rafters
and the tie beam; the upper ends of the vertical
posts are connected by a straining piece, 1 (such
as a tie rod or cable).

queen rod, queen bolt A metal rod which
serves as a queen post.

queen truss See queen-post truss.

quenched Said of a metal which was first heated
and then cooled by contact with a liquid, gas, or
solid, for the purpose of hardening or tempering.

quetta bond A bond in brickwork having ver-
tical voids in which reinforcement is placed
(usually connecting to foundations, floors, and
roof); the voids then are filled with mortar.

quick-break Descriptive of a device having a
high-opening speed regardless of how it is oper-
ated.

quick-change room In a theater, a dressing
room on or near the stage, where actors may
make quick changes of costume or makeup.

quick-closing valve A valve or faucet whose
automatic closure is fast-acting.

quick condition A soil condition in which
water flows upward with sufficient velocity to
reduce significantly the bearing capacity of the
soil through a decrease in intergranular pressure.

785

quick-disconnect device

quick-disconnect device l.A hand-oper-
ated device that provides a means for connect-
ing and disconnecting a gas appliance. 2. A
connector (to a gas supply) that is equipped with
an automatic means for shutting off the supply
when the device is disconnected.

quick-hardening lime A hydraulic lime.

quicklime See lime.

quick-response early-suppression sprin-
kler A fast-response sprinkler that is listed as
providing fire suppression of specific hazards.

quick-response extended coverage sprin-
kler A fire sprinkler that is listed as providing
the characteristics of both a quick-response
sprinkler and an extended coverage sprinkler.

quick-response sprinkler A fire sprinkler
that combines the characteristics of a fast-
response sprinkler and a spray sprinkler.

quicksand Fine sand, sometimes with an
admixture of clay, which is saturated with water
so that it has no bearing capacity at its surface;
fine sand in a quick condition.

quick set See flash set, false set.

quick soil A soil deposit that is reasonably sta-
ble if undisturbed, but suddenly becomes loose
when disturbed.

quick sweep Descriptive of any carpentry or
joinery work having a small radius of curvature.

quilted figure See blister figure.

quilt insulation A blanket-type thermal insu-
lation having, on one or both principal faces, a
flexible facing that is stitched or quilted.

quincunx An arrangement of elements so that
four are symmetrically placed around a central
one.

quincunx plan Same as cross-in-square plan.

quinquefoil, quintefoil See cinquefoil.

quirk l.An indentation separating one ele-
ment from another, as between moldings, or
between the abacus and echinus of a Doric capi-
tal. 2. A V-groove in the finish-coat plaster
where it abuts the return on a door or window;
reduces the possibility of cracking by freeing the
two surfaces.

quirk bead, bead and quirk, quirked bead

l.A bead with a quirk on one side only, as on
the edge of a board. 2. A recessed or double-
quirked bead, where the bead is flush with the

quirk beads

adjoining surface and separated from it by a
quirk on each side. Also called flush bead. 3. A
return bead, in which the bead is at a corner
with quirks at either side at right angles to each
other. 4. A bead with a quirk on its face.

quirk molding, quirked molding A mold-
ing characterized by a sudden and sharp return
from its extreme projection or set-off and made
prominent by a quirk running parallel to it.

quitclaim deed A written instrument whereby
the seller conveys only whatever interest he has in
property, but makes no warranties or representa-
tions as to the nature of that interest or as to the
absence of any limitations or restrictions thereon,
or even that he has any right to the property at all.

quoin, coign, coin In masonry, a hard stone
or brick used, with similar ones, to reinforce an
external corner or edge of a wall or the like;
often distinguished decorative ly from adjacent
masonry; may be imitated in non-load-bearing
materials. Occasionally imitated, for decorative
purposes, by wood that has been finished to look
like masonry.

stone quoins set in brickwork

quoin block Same as corner block.

quoin bonding In masonry, bonding at a cor-
ner with alternating stretchers and headers.

786

quotation

quoin header A quoin which is a header in Quonset hut A prefabricated structure,

the face of a wall and a stretcher in the face of developed during World War II, that has a

the return wall. semicylindrical shape; commonly constructed

quoining Any architectural members which of corrugated steel fastened to arched steel ribs

form a auoin are rigidly fastened to a concrete slab floor.

quotation A price quoted by a contractor, sub-

quom post Same as heelpost, 2. contractor, material supplier, or vendor to fur-

quoin stone A quoin. nish materials, labor, or both.

787

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R l.Abbr. for "radius." 2.Abbr. for "right." 3.
Symbol for the capacity of a pile (for example,
3R indicates three times design capacity). 4.
Symbol for the thennal resistance of a material
or component of construction. 5. Symbol for
electrical resistance.
R.A. Abbr. for "registered architect."
rab A rod or stick used by masons in mixing hair
with mortar.

RAB On drawings, abbr. for rabbet.
rab and dab Same as wattle and daub.

rabbet, rebate 1 . A longitudinal channel, groove,
or recess cut out of the edge or face of a member;
esp. one to receive another member, or one to
receive a frame inserted in a door or window
opening, or the recess into which glass is installed
in a window sash. 2. A rabbet joint. 3. A shallow
recess in one body to receive another, as at the
edges of a pair of doors or windows so shaped as to
provide a tight fit; one half of the edge projects
beyond, and serves as a stop for, the other edge of
each leaf. 4. A rabbet plane.

rabbet, 1

rabbet bead A bead in the reentrant angle of a
rabbet.

rabbet depth In glazing, the depth of the glaz-
ing rabbet; equal to the sum of the bite and the
edge clearance.

rabbeted doorjamb, rabbeted frame A

doorjamb with a rabbet, 3, to receive a door.
rabbeted lock, rebated lock A lock or latch
in which the face is flush with the rabbet on a
rabbeted doorjamb.

rabbeted lock

rabbeted siding Same as drop siding.

rabbeted stop A stop, 1 which is integral with

a door or window frame.
rabbet joint An edge joint formed by fitting

together rabbeted boards or timbers.

rabbet joint

rabbet plane A plane, 1 for cutting a groove
along the edge of a board; open on one side and
having the plane iron (which does the cutting)
extend to the open side.

789

rabbet size

rabbet size In glazing, the actual size of the rab-
beted glass opening; equal to the glass size plus
two edge clearances.

raceway Any channel designed to enclose and
loosely hold electric conductors; may be of metal
or of an insulating material; various types
include rigid conduit, flexible metallic conduit,
nonmetallic conduit, metallic tubing, under-
floor raceways, cellular floor raceways, surface
metal raceways, structural raceways, wireways
and bus ways, and auxiliary gutters or moldings.

raceway cable distribution system A sys-
tem for distributing cable in an open or closed
metal tray that is suspended within a false ceil-
ing from the structural floor above; generally
used in large buildings where complex cable dis-
tribution systems require special support.

rack-and-pinion elevator An elevator hav-
ing electrically driven rotating gear pinions
mounted on the car; rotation of the gear pinions
moves the car up or down on a stationary gear
rack which is mounted vertically in the hoistway.

racked Descriptive of timbering which is braced,
providing additional support to prevent deforma-
tion.

racking 1. The distortion or movement of a
frame. 2. The out-of-plumbness of a structure, or
any of its components, that are a result of seismic
stress or wind acting on the structure; may also
result from thermal expansion and contraction.

racking back The stepping back of courses of
brick during the construction phase of a wall,
usually in expectation of the wall's completion
at a later date.

racking load A load applied in the plane of an
assembly in such manner as to lengthen one
diagonal and shorten the other.

rack saw A saw having wide teeth.

rad Abbr. for radiator.

rad and dab Same as wattle and daub.

radial arch Same as segmental arch.

radial arch roof A roof supported by a system
of arches radiating from a central point.

radial-arm saw, radial saw A circular saw
which is suspended from, and moves along, a
cantilevered arm, mounted above the saw table;
the blade can be set at any angle (or tilted) with
respect to the work.

radial bar Same as radius rod, 2.

radial-blade fan A heavy-duty industrial fan
used for severe service, e.g., where foreign mate-
rial (such as wood chips) passes directly through
the fan.

radial brick, radius brick An arch brick, 1.

radial-cut See quarter-cut.

radial grating Nonrectangular grating, in
which the bearing bars extend radially from a
common center and the cross bars have a pattern
of concentric circles.

radially-cut grating Rectangular grating that
is cut into panels shaped as annular segments, for
use in circular or annular areas.

radial road One of a group of roads which radi-
ate outward from the center of a city, as spokes
on a wheel.

radial saw See radial-arm saw.

radial shrinkage The shrinkage of wood
across the growth rings during drying; the loss in
dimension along the radius of a log.

radial step Same as winder.

radiance The rate of radiant emission per unit
solid angle and per unit projected area of a source
in a stated angular direction from the surface.

radiant glass Glass containing radiant heating
elements.

radiant heating Heating which results from
heat transmitted by radiation, as contrasted with
heat transmitted by conduction or convection.

radiant heating system A system for heating
a room or space by means of heated surfaces
(such as panels heated by the flow of hot water
or electric current) which provide heat primarily
by radiation.

radiant panel test An ASTM standard
method of test for the surface flammability of a
material, using a radiant heat source.

radiating brick An arch brick, 1.

radiating chapels Chapels projecting radially
from the curve of an ambulatory or rarely of an
apse.

radiation The transmission of heat through
space by means of electromagnetic waves; the
heat energy passes through the air between
the source and the heated body without heating
the intervening air appreciably.

radiation-retarding door See lead-lined door.

790

raft footing

radiation-retarding frame See lead-lined
frame.

radiation-shielding concrete High-density
concrete suitable for enclosing nuclear installa-
tions; its aggregate has a high specific gravity;
contains a high proportion of atoms having a
high atomic weight or consisting of minerals and
synthetic glasses of substantial boron content.
Also see heavyweight aggregate, boron-loaded
concrete.

radiation-shielding door See lead-lined door.

radiator A heating unit usually exposed to view
within the room or space to be heated; transfers
heat by radiation to objects within visible range,
and by conduction to the surrounding air, which
in turn is circulated by natural convection; usu-
ally fed by steam or hot water.

radiator

radius brick See arch brick, 1.

radius diffusion The horizontal axial distance
an airstream travels after leaving an air outlet
before the maximum stream velocity is reduced
to a specified terminal value.

radius gauge See Met gauge.

radius of gyration In mechanics, the distance
from the axis to a point such that, if the whole
mass of a body were concentrated at it, the
moment of inertia would remain unchanged.

radius rod l.A plastering tool; a wooden arm
fixed at one end to a mold and attached at the
other end to a center about which it swivels; a
gig stick. 2. A long wooden arm with a marker at
one end for tracing large curves.

radius shoe A zinc plate attached to one side
of a plasterer's radius rod at midpoint.

radius tool A radius rod.

radius wall A curved wall that is a segment of a
circle.

radon A gaseous emanation produced by the
radioactive decay of radium, given off by some
soils and rocks; it may collect and constitute a

health hazard in buildings with poor ventila-
tion.
rafter One of a series of inclined structural mem-
bers from the ridge of the roof down to the eaves,
providing support for the covering of a roof. For
special types of rafters, see beveled rafter, binding
rafter, common rafter, compass rafter, compound
rafter, fly rafter, hip rafter, jack rafter, knee rafter,
notched rafter, principal rafter, valley rafter.

RAFTER

JOIST

rafter

rafter fill Same as beam fill.

rafter house In the Chesapeake Bay area of
colonial America, a house of a relatively tempo-
rary nature, in which the lower ends of the roof
rafters rested directly on the ground; a forerun-
ner of the modern A-frame house.

rafter lookout See lookout, 1.

rafter plate A plate, 2 which supports the
lower end of rafters and to which they are fixed.

rafter roof A double roof structure that usually
has no purlins; if present, they act merely as
stiffeners.

rafter table A table of values, usually on a steel
square, used by carpenters to determine the
lengths and angles of cut for rafters for a roof.

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rafter table

rafter tail The part of a rafter which overhangs

the wall.
raft footing See floating foundation.

791

raft foundation

raft foundation Same as floating foundation.

rag A large roofing slate that has one edge
untrimmed.

rag bolt Same as lewis bolt.

rag felt An asphaltic felt fabricated from the
fibers of rags; used for roofing paper and shingles.

raggle, reglet, raglin 1. A manufactured unit,
often of terra-cotta, having a groove to receive
flashing; also called a raggle block or flashing
block. 2. A groove cut in stone or brickwork to
receive flashing.

LEAD PLUG

FLASHING

raggle block See raggle, 1.

rag joint Same as rubbed joint.

raglet A raggle.

raglin A raggle.

rag-rolled finish A decorative effect on a
painted surface; made by rolling a piece of
twisted rag over a coat of wet paint so as to
remove portions of it and show the color of the
base coat. A similar effect can be achieved with
a special paint roller.

rag rubble A type of rubblework composed of
thin small stones.

ragstone l.A rough, shelly, sandy limestone
with layers of marl and sandstone. 2. In masonry,
stone quarried in thin blocks or slabs.

ragwork 1 . Crude masonry, laid in a random
pattern of thin-bedded, undressed stone, such as
flagging; most commonly set horizontally. 2.
Polygonal rubble, set on edge, that serves as an
exterior facing.

rail 1. A bar of wood or other material passing
from one post or other support to another; a
hand support along a stairway. 2. A structure
consisting of rails and their sustaining posts,
balusters, or pillars, and constituting an en-
closure or a line of division, as a balcony rail.
3. A horizontal piece in a frame or paneling as

ragwork, 1

ji A

TOP RAIL

1 +

1 UPPER I

MEETING RAIL

1 1

1 I

BOTTOM
1 RAIL 1

1 1

rail, 3

a door rail, or in the framework of a window
sash.

rail bead A cock bead when on a uniform con-
tinuous surface, and not at an angle, reveal, or
the like.

rail bolt A handrail bolt.

rail fence A fence in which the rails are set into
the posts; adjoining rails either butt against each
other or overlap. Also called a zigzag fence.

railing 1. Rails, collectively, or a combination
of rails. 2. Any openwork construction or rail
used as a barrier or the like.

rail pile A pile fabricated from railroad rails
which are welded together and driven as a unit.

railroad flat A narrow apartment whose rooms
are in a straight line; one must pass through each
room to get to the next one because there is no
internal corridor. Only the front and rear rooms

792

raised flooring system

have windows; air shafts along one or both sides
of the apartment provide ventilation and a little
light in the interior rooms. Primarily con-
structed on the east coast of America in the
1880s; also called a dumbbell tenement.

rail steel reinforcement Steel reinforcing
bars that have been hot-rolled from standard T-
section rails.

rainbow roof l.Same as compass roof. 2.
Same as ship's bottom roof.

rain cap A device which is installed at the
upper termination of a chute or vent, above the
roof of a building, to prevent rain from entering
the interior of the chute; often includes a screen
to prevent the entry of birds.

F=l

rain cap with a hirdscreen

raindrop figure A mottled figure in wood ve-
neer; resembles a raindrop pattern.
rain leader See downspout.

rainproof Constructed, protected, and/or
treated to prevent rain from interfering with the
successful operation of apparatus.

raintight Constructed, protected, and/or treated
so that exposure to intense rainfall will not result
in the entrance of water.

rainwater conductor Same as downspout.

rainwater conductor head, rainwater hop-
per head Same as leader head.

rainwater head See leader head.

rainwater hopper A hopper-shaped leader
head.

rainwater pipe A downspout.

rainwater shoe At the foot of a downspout, a
short fitting with a bend to discharge the rain-
water clear of the building.

raised barn Occasionally, a synonym for a
bank barn.

raised basement A basement whose floor level
is much higher than usual, so that its ceiling is
well above (usually one story above) ground level.

raised cottage 1. Cottage on stilts or built-up
piers to protect it from groundwater. 2. Same as
raised house.

raised floor A floor fabricated entirely of
square plates that rest on interlocked pedestals
attached to the structural floor of a building.
The plates usually are fabricated of aluminum
and are covered with cork, carpet, or vinyl tiles.
The plates can be removed to provide conve-
nient access to the cables beneath; used exten-
sively in computer rooms.

FLOOR FUTES
REMOVED TO GAIN
ACCESS TO CABIE

LOCKING

pedestal

raised floor showing floor plates on pedestals

raised floor: cutaway detail of a plate adjacent to the wall

raised flooring system A system of flooring
consisting of completely removable and inter-
changeable floor panels which are supported on

793

raised girt

adjustable pedestals and/or stringers to allow free
access to the area beneath.
raised girt, flush girt, raised girth A girt

which is parallel to the floor joists and level with
them.

raised grain 1 . In dressed softwood lumber, sur-
faces in which the hard summerwood is raised
above the soft springwood. 2. In hardwoods,
fibers protruding above the normal surface; usu-
ally caused by wetting.

raised house In the American South, a house or
cottage having a raised basement; this cellar,
whose floor is at ground level, often functions as a
service area, shop, office, or stable. The main floor
(one story above) contains the family living quar-
ters. The exterior walls typically are whitewashed
brick, stone, plaster, or stucco. A porch (galerie),
extends across the entire facade and sometimes
along both sides as well; French doors opening
onto the porch promote the flow of air during very
hot weather. Also see plantation house.

n if mm ii

BMnmMiqm- " : rtLiJl B.i r j.i II u..i. I

raised house (1801)

raised joint Same as excess joint.

raised molding Same as bolection molding.

raised panel, fielded panel A panel with the
center portion thicker than the edges or project-
ing above the surrounding frame or wall surface.
When exposed on both sides (as on both sides of
a door), it is called a double raised panel.

raised porch In French Vernacular architec-
ture of Louisiana in the 18th century, the galerie
of a raised house.

raised table A flat horizontal raised surface
which is large in area compared to its elevation
above its surroundings.

raising See lifting.

raising bee See barn raising.

raising hammer A hammer with a long head
and a rounded face, used in lifting sheet metal.

raising piece A piece of timber laid on a brick
wall, or on the top of posts or puncheons of a
timber-framed house, to carry a beam or beams;
a template.

raising plate A horizontal timber resting on a
wall, or upon vertical timbers of a frame, and
supporting the heels of rafters or other frame-
work; also called a wall plate.

rajones The term for shingles in Spanish Colo-
nial architecture in the American Southwest.

rake 1. A slope; an inclination; e.g., the inclina-
tion (from the horizontal) of an auditorium
floor. 2. A board or molding along the sloping
edge of a gable; covers the edges of the siding. 3.
On the roof of an early colonial house, a flat
board covering the lower ends of the rafters.

raked Said of any surface that is inclined with
respect to the horizontal, such as a raked molding,
or the inclined surface of a raked cornice in a tri-
angular pediment.

rake dimension Same as pitch dimension.

raked joint A joint made by removing the sur-
face of mortar, while it is still soft, with a square-
edged tool; is difficult to make watertight;
produces marked shadows and tends to darken
the overall appearance of a wall.

raked joint

raked molding Same as raking molding.
rake-out, raking out In masonry, preparing

mortar joints for pointing.
raker 1 . A tool for raking out decayed mortar

from the joints of brickwork, preparatory to

repointing them. 2. Any inclined member, as a

brace, or pile. 3. A raking shore.
raker pile Same as batter pile.
raking Inclining; having a rake or inclination.
raking arch Same as rampant arch.

794

rampant vault

raking back Same as racking.

raking bond A method of bricklaying in which
the bricks are laid at an angle in the face of the
wall; either diagonal bond or herringbone bond.

raking coping A coping set on an inclined
surface, as at a gable end.

raking corbel table A corbel table on a slant.

raking cornice A cornice following the slope
of a gable, pediment, or roof.

raking cornice

raking course A course of bricks laid diago-
nally between face courses of a thick wall to
strengthen it.

raking flashing A flashing, parallel to the roof
slope, which is used to cover the intersection of
a chimney and a sloping roof.

raking molding, raked molding l.Any
molding adjusted at a slant, rake, or ramp. 2.
Any overhanging molding which has a rake or
slope downward and outward.

raking molding

raking»out In brickwork, preparing mortar

joints for pointing.
raking pile A pile that is not driven vertically;

a batter pile.

raking riser On stairs, a riser, 1 which is not per-
pendicular to the tread, but inclined inward to
permit more footroom on the tread below.

raking shore, inclined shore An inclined
member which supports a wall; a raker, 3.

raking stretcher bond Similar to stretcher
bond, except that each stretcher is displaced
with respect to the one below, so that it overlaps
it by a quarter of a brick rather than a half brick.

raking stretcher bond

raking strut A strut that has an inclination
with respect to the horizontal; especially used in
pairs between principal rafters and tie beams.

ramada l.In Spanish architecture and deriva-
tives, a rustic arbor or similar structure. 2. An
open porch.

rambler A one-story dwelling; a ranch house.

rammed earth A material usually consisting
of clay, sand, or other aggregate (such as sea
shells) and water, which has been compressed
and dried; used in building construction.

rammer A power-driven tool used to compact
soil or other granular material.

ramp l.A sloped surface connecting two or
more planes at different levels. 2. A concave
sweep in a vertical plane. 3. The paved area of
an airport between the terminal building and
the taxiways, used to park airplanes during
loading and unloading. 4. According to the
Americans with Disabilities Act, a walking
surface whose running slope is less steep than
l-in-20.

ramp and twist Any surface that rises and
twists simultaneously.

rampant arch, raking arch An arch in
which the impost on one side is higher than that
on the other. (See illustration p. 796.)

rampant vault A continuous wagon vault, or a
cradle vault, whose two abutments are located

795

rampart

rampant arch

1
1

— 1 —

1
1

rampant vault

on an inclined plane, such as a vault supporting
or forming the ceiling of a stairway.

rampart An elevated earthen wall for purposes
of defense, located on the inner side of a ditch
surrounding a bastioned fort.

rampart-walk Same as walk-walk.

ramped step A step with a sloping tread.

ramped steps See stepped ramp.

ramping vault Same as rampant vault.

ram's-horn figure A curly, wavy figure in
wood veneer, like fiddleback.

ranee A shore.

ranch house A rambling one-story house, espe-
cially popular in the mid-20th century; usually
designed to emphasize the horizontal aspects of
the house. Typically characterized by: an asym-
metrical plan; exterior wall cladding of stucco,
brick, wood, or some combination thereof; a
low-pitched roof with eaves having a moderate-
to-wide overhang, a hipped, cross-gabled, or side-
gabled roof; exposed rafters; ribbon windows,

windows decorated with shutters; frequently, glass
sliding doors that open onto a porch or patio at
the side or rear of the house; an attached garage.

ranch-type shingle A rectangular (usually
asbestos-cement) shingle which is lapped at the
top and on the side.

rand (Brit.) A border, or a fillet cut from a bor-
der in the process of straightening it.

randle bar A horizontal iron bar, built into a
jamb of a fireplace, that projected over the fire so
that pots could be suspended from it for cooking;
also see chimney hook, fireplace crane, trammel.

random ashlar Masonry in which rectangular
stones are set without continuous joints and
appear to be laid without a fixed pattern; also
called random bond or random work.

random bond See random ashlar.

random course One of a number of horizontal
stone masonry courses which are of unequal
height.

random length In piping, see mill length.

random line In surveying, a trial line toward a
fixed terminal point which is invisible from the
initial point.

random noise A type of noise comprised of
transient disturbances which occur at random
times; its instantaneous magnitudes are specified
only by probability distribution functions which
give the fraction of the total time that the mag-
nitude lies within a specified range.

random paving Paving using irregularly shaped

stones.
random range ashlar Same as random work.
random rubble Same as rubblework.

random shingle One of many shingles of uni-
form length, but of any width.

random slate One of many slate shingles
installed in irregular pattern, using varying sizes.

random tooled ashlar See random work.

random widths Boards, lumber, shingles, etc.,
of nonuniform widths.

random work, broken ashlar, random
range ashlar, random range work 1.

Random stonework. 2. Masonry of rectangular
stone not laid in regular courses, but broken up
by the use of stones of different heights and
widths, fitted closely.

796

rated horsepower

random work

range 1 . In masonry, a row or course, as of stone.
2. A line of objects in direct succession, as a
range of columns.

range closet A latrine having a number of seats.

ranged rubble Same as rubblework.

range hood An open metal enclosure over
cooking surfaces through which air is drawn in
from the surrounding spaces, entraining grease,
heated air, and odors.

range-in, wiggling-in A trial-and-error pro-
cedure for placing a surveyor's instrument on a
previously established line.

range masonry, rangework See coursed
ashlar.

range pile A pile which serves as a guide for
locating other piles.

range pole Same as range rod.

ranger Same as wale.

range rod, range pole A wood, fiberglass, alu-
minum, or steel lining pole used by surveyors as a
sighting rod for locating points or directions of
lines in marking alignment; approx. 1 in. (2.5 cm)
thick and 6 to 10 ft (approx. 2 to 3 m) long; usu-
ally painted with alternate red and white bands.

rangework Masonry in which the stones are of
equal height within each course, but all courses
need not be of the same height.

ranging bond In masonry, a chain bond
formed by small strips of wood at the face of the
wall, commonly laid in the joints, and projecting
slightly to provide a nailing surface for battens,
furring, etc.

ranging pole Same as range rod.

ranked A term preceded by a digit (usually
from two to nine) that indicates the number of
windows across an upper floor of the facade of a
house. For example, a six-ranked house has six

windows across the upper floors; on the ground
floor, the entry door is tallied as one of the win-
dows, so it has five windows plus the door.

rapid-curing asphalt Liquid asphalt com-
posed of asphalt cement and a naphtha or
gasoline-type diluent of high volatility.

rapid-curing cutback Same as rapid-curing
asphalt.

rapid-hardening cement A high-early-
strength cement.

rapid-start fluorescent lamp A fluorescent
lamp designed for operation with a ballast hav-
ing a low-voltage winding for preheating the
electrodes and for initiating an arc; may be oper-
ated on preheat fluorescent circuits; does not
require a starter or the use of high voltage.

rasp A coarse file having its surface dotted with
protruding pointed teeth.

ratchet brace A brace, 3 with a ratchet-driven
chuck, permitting its use in confined spaces
where complete circular sweeps of an ordinary
brace would be impossible.

ratchet brace

ratchet drill A hand-driven drill, 1 which has a
ratchet-driven chuck; used in confined spaces.

ratchet drill

ratchet screwdriver See spiral ratchet screw-
driver.

rated current The current that an electrical
device can carry, under specified conditions,
without resulting in overheating or mechanical
overstress.

rated horsepower Of an engine or prime
mover, the maximum horsepower that can be
provided under normal, continuous operation.

797

rated lamp life

rated lamp life 1 . The average life of a lamp of
a given type, as determined from a large sample
operated under laboratory conditions; the aver-
age life of a group of lamps which are operated
under variable conditions may not equal the
rated lamp life. 2. For lamp types whose lumi-
nous output drops to a very low value before the
lamps cease to operate: the time when the out-
put of a large sample of lamps under controlled
laboratory conditions reaches a specified frac-
tion of the initial output.

t£ 60

-in 40

40 ao i20

% OF RATED LIFE

ISO

% rated lamp life vs. % of initial lamps which survive
A life expectancy curve for incandescent lamps

rated load In vertical transportation, the load
in pounds or kilograms which an elevator, lift,
dumbwaiter, or escalator is designed to lift at its
rated speed.

rated speed The speed in feet (or meters) per
minute at which a device, apparatus, con-
veyance, elevator, etc., is designed to operate in
the upward direction with the rated load.

rate of decay Same as decay rate.

rate of growth Same as growth rate.

rath A primitive fort in Ireland, many of which
still exist today; the defensive structure includes
ramparts of stone or earth as well as some rudi-
mentary form of housing.

rating correction factor The fraction by
which the rated electrical load or current must
be multiplied to obtain the appropriate figure to
estimate the total load for design purposes.

ratio of reduction See reduction ratio.

rat stop In masonry wall construction, a barrier
to prevent rats from burrowing down along the
exterior of a foundation wall.

rat-trap bond A modification of Flemish bond
with the stretchers laid on edge.

rauchkammer A room in a garret in a Penn-
sylvania Dutch colonial house that was set aside
for the curing of meat. An opening in the chim-
ney stack that passed through this space allowed

rat-trap bond

smoke to enter the garret, and the meats to be
cured were hung from hooks attached to the
underside of the roof framing.

ravelin, demilune In fortifications, a project-
ing outwork forming a salient angle.

raveling In asphalt pavement, the progressive
disintegration by the dislodgement of aggregate
particles, from the surface downward or from the
edges inward.

raw brick An unfired brick, before it has been
inserted in a kiln.

raw linseed oil Linseed oil which has been
refined but has not undergone further treatment,
such as boiling, blowing, or bodying.

Rawl plug A proprietary name for a concrete
insert.

raw sewage Untreated sewage.

raw water 1. In ice making, any water used for
ice making except distilled water. 2. Water, from
any source, that requires treatment before it can
be used, e.g., as in steam generation.

ray See medullary ray.

rayon Continuous -filament yarn composed of
regenerated cellulose; similar in chemical struc-
ture to natural cellulose fiber but contains shorter
polymer units; usually made by the viscose process.

Rayonnant style The middle phase of French
Gothic architecture in the 13th and 14th cent.,
characterized by radiating lines of tracery.

RBM Abbr. for reinforced brick masonry.

RC, R/C Abbr. for reinforced concrete.

RC asphalt Same as rapid-curing asphalt.

RC curves (room criterion curves) A
series of curves of octave-band sound spectra;
used to provide a single-number rating of the
noisiness of an indoor space. A measured
octave-band spectrum is compared with this set
of curves to determine the RC level of the space
in which the measurements were made.

798

rear vault

Rayonnant style

RCD Abbr. for "residual current device."

RCP Abbr. for "reinforced concrete pipe."

% RD On drawings, abbr. for quarter-round.

Vz RD On drawings, abbr. for half-round.

RD 1 . Abbr. for roof drain. 2 . On drawings , abbr.
for "round."

reach The section of a sewer between structures.

reach-in refrigerator A prefabricated reach-
in compartment for cooling food and/or bever-
ages.

reaction pile Same as anchor pile.

reaction wood Wood which results from ab-
normal growth.

reactive aggregate Aggregate containing sub-
stances capable of reacting chemically with the
products of solution or hydration of the portland
cement in concrete or mortar under ordinary
conditions of exposure; in some cases causes
harmful expansion, cracking, or staining.

reactive concrete aggregate See reactive
aggregate.

reactive silica material Any material, such
as fly ash, natural pozzolan, or pulverized silica,

which reacts at high temperatures with portland
cement or lime during autoclaving.

reader's desk The middle desk in a three-
decker pulpit.

readily accessible Providing direct access (e.g.,
to piping, wiring, air-conditioning controls, etc.)
without requiring the removal or movement of a
panel or similar obstruction.

ready condition Said of a wet alarm valve in a
fire sprinkler system in which the piping is filled
with water from a water supply of stable pressure;
in this condition, there is no water flow from any
outlet of the system downstream from the alarm
valve sealing assembly.

ready-cut house Same as prefabricated house.

ready-mixed See mill-mixed.

ready-mixed concrete Concrete for delivery
to a site in an unhardened state for immediate use.

ready-mixed glue See mixed glue.

real estate Property in the form of land and
all its appurtenances, such as buildings erected
on it.

real property Land, everything growing on it,
and all improvements made to it. It usually
includes rights to everything beneath the surface,
and at least some rights to the airspace above it.

reamer A tapered bit having sharp, spiral,
fluted cutting edges along the shaft; used to
enlarge an opening, to cut the burrs from the
inside of pipe, etc.

for

enl;

argmg

reaming iron

rivet holes.

rear arch l.An inner arch of an opening
which is smaller in size than the external arch of
the opening and may be different in shape. 2.
See arriere-voussure.

rear girt A girt that runs horizontally along the
rear wall of a house; see illustration under timber-
framed house.

rear vault 1 . A small vault, 1 over the space
between the tracery or glass of a window and the
inner face of the wall. 2. An arriere-voussure.
(See illustration p . 800.)

799

rear yard

rear vault, 1

rear yard The yard across the full width of a
plot, extending from the rear line of a building
to the rear property line.

reasonable care and skill See due care.

reason piece Same as raising piece.

rebar A steel bar having ribs or slightly projecting
patterns on its surface to provide a greater bond
with concrete when used in reinforced concrete.

rebate See rabbet.

rebound Wet shotcrete which bounces off a
surface against which it is projected.

receipt of bids The formal action taken by an
owner in receiving sealed bids that have been
invited or advertised in accordance with the
owner's intention to award a contract.

receptacle A device which is installed in an
outlet box to receive a plug for the supply of
electric current to an appliance or portable
equipment.

receptacle outlet An electrical outlet where
one or more receptacles are installed.

receptacle plug A device, usually connected
to an electric cord, which is inserted in a recep-
tacle to establish an electric connection with
the electrical supply.

reception wall Same as retention wall.

receptor 1 . A channel-shaped, telescoping mem-
ber which adapts the frame of a window to the size
of the window opening; an adapter. 2. The shal-
low base pan for a shower.

receptorium A kind of parlor which usually

adjoined an ancient Roman basilica.
recess l.Any shallow depression in a surface.

2. A shallow depression in a floor; a sinkage.
recess bed See wall bed.
recessed arch An arch with a shorter radius

set within another of the same shape.
recessed bead See quirk bead, 2.
recessed column A round column set into a

recessed space that serves as a niche; primarily in

a church.
recessed dormer A dormer, part or all of

which is set below the main roof surface; also

called an inset dormer.
recessed fitting Same as drainage fitting.
recessed fixture A lighting fixture which is

recessed into a ceiling so the lower edge of the

fixture is flush with the ceiling.

CEILING

.METAL HOUSING
REFLECTOR LAMP

recessed fixture

recessed head For a mechanical fastener, a

head having a specially formed indentation

which is centered in its top surface.
recessed heater A self-contained heating unit

(see electric heating elements), set into a wall.
recessed joint Same as recessed pointing,
recessed luminaire See recessed fixture,
recessed pointing In masonry, a joint in

which the mortar is pressed back, about l A in.

(6 mm) from the wall face, to protect the mortar

from peeling.

recessed pointing

recessed sprinkler In a fire-protection sys-
tem, one of many pendant sprinklers located
within cups recessed into the ceiling.

800

reduced-pressure-principle backflow preventer

recharge, groundwater recharge The re-
plenishment of water in the ground, e.g., through
injection or infiltration from trenches outside
the construction area.

reciprocating drill Same as push drill.

reciprocating saw Similar to a saber saw but

with a heavier blade and a motor with greater

power.
recirculated air Air which is withdrawn from

an air-conditioned space and passed through the

air conditioner before being supplied once again

to the conditioned space.
recoating time The minimum time between

the application of one coat of paint and the

application of the next coat.

reconditioned wood Hardwood lumber that
has been steam-dried to correct defects, such as
collapse, warp, etc., that occurred during the
original drying process.

reconstituted marble See artificial stone.

reconstituted stone Same as artificial stone.

reconstruct To reproduce a building in the
same form and detail as it had been previously.

reconstructed stone Same as artificial stone.

record drawings Construction drawings re-
vised to show significant changes made during
the construction process, usually based on
marked-up prints, drawings, and other data
furnished by the contractor to the architect.

record sheet On a construction job, a sheet or
printed form for keeping a record, usually of
materials delivered, number of men working at
the various trades, hours worked, etc.

recovery capacity See heating capacity.

RECP On drawings, abbr. for receptacle.

rec. room Abbr. for "recreation room."

rectangular tie A wall tie of heavy wire that
has been bent into the shape of a closed rect-
angle, about 2 in. by 6 in. (5 cm by 15 cm).

}

rectangular tie

Rectilinear style See Perpendicular style.
rectilinear tracery See perpendicular tracery.

rectory The residence of a rector.

recycled concrete Hardened concrete which
has been crushed for re-use as an aggregate.

redan A diminutive ravelin.

red brass, rich low brass A metal alloy con-
taining 85% copper and 15% zinc; has high
corrosion resistance; can take a high polish; gen-
erally available in flat sheets, rod, wire, and tube.

red cedar See eastern red cedar.

red fir Same as Douglas fir.

red gum Same as gum, 1.

red heart Decayed heartwood; in some woods it
is red in color although it is commonly called
brown rot.

red lauan See Philippine mahogany.

red lead A lead compound, lead tetroxide; bright
red to orange-red in color; used in corrosion-resis-
tant paints as a rust inhibitor on iron and steel.

red locust See locust.

red oak An oak of eastern North America; the
wood is a light brown or red color; relatively
heavy, hard, strong, coarse-grained; used esp. for
clapboards, also for interior finish.

red ocher A mixture of hematites; any of a
number of natural earths used as red pigments.

redoubt A small fortification detached from
the principal site.

red oxide A natural or synthetic inorganic red
pigment; used in paints to provide a lightfast
color at a low cost; grades vary in purity, particle
size, and brightness.

red rosin paper A type of building paper.

red-shortness Brittleness of iron or steel at a
red hot temperature.

redevelopment The restoration and improve-
ment of an existing structure or property.

reduced level The level at a construction site
after excavation, usually with respect to a given
datum.

reducing power A measure of the strength of
a white pigment in making another pigment
appear lighter in color.

reduced-pressure-principle backflow pre-
venter A backflow preventer that consists of
two independently-operating check valves that

801

reduced size vent

TLSTCOCK 1!M<<h;K

I I Vrtl ■/!

reduced-pressure-principle backflow preventer

are spring-loaded in a closed position and are

separated by a chamber in which there is an

automatic relief vent to the atmosphere that is

spring-loaded in the open position.
reduced size vent A dry vent that is smaller

than one specified by code.
reducer 1. A thinner or solvent; used to lower

the viscosity of a paint, varnish, or lacquer. 2. A

reducing pipe. 3. A reducing valve.

reduction ratio In stone crushing, the ratio of
the maximum dimension of stone before crush-
ing to the maximum dimension after crushing.

redwood A very durable, straight-grained,
high-strength, moderately low-density softwood
from the Pacific Coast of the US; esp. resistant
to decay and insect attack; light red to deep red-
dish brown in color; used primarily for construc-
tion, plywood, and millwork, where durability is
required.

redwood bark Shredded bark of the redwood
tree; sometimes used as loose-fill thermal insu-
lation.

reed 1 . A small convex molding, usually one of
several set close together to decorate a surface.
2. (pi.) Same as reeding. 3. A straw-like material
prepared for thatching a roof.

reed house Same as brush house.

reeding An ornament of adjacent, parallel, pro-
truding, half-round moldings (reeds); the reverse
of fluting. Also see cabling.

reducer, 2

reducing coupling Same as reducer, 2.

reducing joint A joint between two lengths of
electric conductors of unequal size.

reducing pipe A pipe coupling, with inside
threads, having one end with a smaller diameter
than the other; both openings have the same
center line; for connecting pipes of different size.

reducing pipe fitting Any fitting, 1 which is
used to connect pipes of different size.

reducing socket Same as a reducing pipe fitting.

reducing valve See pressure-reducing valve.

reduct A small piece cut from a larger piece, mem-
ber, etc., to make it more uniform or for symmetry.

reduction of area The difference between the
original cross-sectional area of a test specimen
before being subjected to tension and the area of
its smallest cross section after rupture; expressed
as a percentage of the original cross-sectional
area of the specimen.

reeding

reel and bead See bead and reel.

reentrant angle An internal angle usually less
than 90°.

reentrant corner An internal or inside cor-
ner; usually used to describe angles less than 90°.

REF On drawings, abbr. for "refer" or "reference."

refectory A hall in a convent, monastery, or
public secular institution where meals are eaten.

reference line Any line which can serve as a
reference or base for the measurement of other
quantities.

reference mark A supplementary mark of
permanent character close to a survey station, to

802

refraction

refectory

which it is related by an accurately measured dis-
tance and azimuth (or bearing); the connection
between a survey station and its reference mark
or marks must be of sufficient precision and
accuracy to permit the reestablishment of the
station on the ground from its marks.

reference standards Technical and generic
data published by a technically competent orga-
nization (such as the ASTM or BRE) that are
generally accepted by the building construction
industry; they provide acceptability criteria by
which products or materials may be evaluated.

reference standard specification A non-
proprietary specification based on accepted stan-
dards, or on requirements set by an acceptable
authority, which describes products, materials,
or pieces of equipment to be incorporated in a
building project.

reference temperature In the definition for
degree-day, an indoor temperature of 65 °F
(18.3°C) in the US, or 60° (15.6°C) in Britain.

refined tar l.Tar from which water has been
evaporated or distilled until a desired consis-
tency is reached. 2. A bituminous product pro-
duced by fluxing tar residuum with tar distillate.

reflash The reignition of a flammable material
by a hot source after the flames have been extin-
guished.

reflectance The ratio of the reflected flux to
the flux incident on a surface.

reflectance coefficient, reflectance factor
Same as reflectance.

reflected glare Glare resulting from specular
reflection of high brightness in polished or glossy
surfaces in the field of view. Also see specular
surface.

reflected plan A plan, viewed from above, laid
out as if it were projected downward on an upper
surface (such as a ceiling); thus a member seen
on the left from below appears to the right on
the plan.

reflection The change of direction which a ray
of light, sound, or radiant heat undergoes when
it strikes a surface; also see law of reflection.

reflective glass Window glass which has been
coated on the outside with a transparent metal-
lic coating to reflect a significant fraction of the
light and radiant heat which strikes it.

reflective insulation 1. Thermal insulation
in sheet form which has one or both surfaces
faced with a reflective foil of comparatively low
heat emissivity; used in building construction
with a reflective surface facing an air space, to
reduce the transfer of heat (by radiation) across
the air space. 2. Thermal insulation whose per-
formance depends on the reduction of transfer of
radiant heat across air spaces by the use of one or
more surfaces having high thermal reflectance
and low emittance.

reflectometer A photometer for measuring
the reflectance of a material.

reflector l.A device that redirects light or
sound by reflection. 2. The device on a lumi-
naire which controls the distribution of light
from the lamp by reflection.

reflector lamp An incandescent lamp in
which part of the bulb serves as a reflector, e.g.,
a PAR lamp.

reflector lamp

reflux valve See check valve.

REFR l.On drawings, abbr. for refractory.

2. On drawings, abbr. for "refrigerate."
refraction The change in direction of a light
ray or a sound ray in passing from one medium to
another.

803

refractory

refractory A material, usually nonmetallic,
used to withstand high temperatures.

refractory aggregate A material having refrac-
tory properties; when bound together into a con-
glomerate mass by a matrix, forms a refractory
body.

refractory brick A brick capable of with-
standing high temperatures.

refractory cement Cement esp. manufac-
tured for use in furnace and oven linings; often a
mixture of fireclay with crushed brick, silica
sand, or sodium silicate.

refractory concrete Concrete having refrac-
tory properties; suitable for use at high tempera-
ture; usually made with calcium alumina te
cement and refractory aggregate.

refractory insulating concrete Refractory
concrete having low thermal conductivity.

refractory insulation Thermal insulation
which may be used at temperatures above
1500°F (816°C).

refractory materials Materials (such as bricks
or blocks) that do not deform significantly or
change chemically when subject to high temper-
atures.

refractory mortar A mortar having refractory
properties that make it suitable for use at high
temperatures.

refrigerant The medium of heat transfer in a
refrigeration system which absorbs heat by evap-
oration at low temperature and pressure and
gives up heat on condensing at higher tempera-
tures and pressures.

refrigerant charge The quantity of refriger-
ant in a refrigeration system.

refrigerant compressor unit A packaged
unit comprising a pump suitable for compressing
refrigerant gas, associated controls and acces-
sories, and a prime mover which may be an inte-
gral part of the compressor or mounted with the
compressor on a common base.

refrigerant condenser See condenser.

refrigerant condensing unit See condens-
ing unit.

refrigerating medium Any substance whose
temperature is such that it is used to lower the
temperature of other bodies or substances below
the ambient temperature.

refrigeration The process by which heat is

absorbed from a body or substance by expansion
or vaporization of a refrigerant, lowering its body
temperature and maintaining the temperature
below its surroundings.

refrigeration cycle A repetitive sequence of
thermodynamic processes in which a refrigerant
absorbs heat from a controlled space at relatively
low temperature; then the heat is rejected else-
where at a higher temperature, and the process is
repeated.

refrigeration system A closed-flow system in
which a refrigerant is compressed, condensed,
and expanded to produce cooling at a lower tem-
perature level and rejection of heat at a higher
temperature level for the purpose of extracting
heat from a controlled space.

refrigerator A container and a means of cool-
ing it, such as a commercial refrigerator, service
refrigerator, etc.

refurbish To make fresh again without demoli-
tion and replacement of the original building;
i.e., to renovate.

refusal The depth below which a pile cannot be
driven.

refuse An approximately even mixture of
garbage and rubbish by weight; contains up to
50% moisture and 7% incombustible solids.
Also see trash.

refuse chute A means of transporting waste
materials by chute, from the point of disposal in
high-rise residential (or office building) to a
refuse collection room at the base of the chute.
See also gravity-type refuse chute.

refuse compactor A motor-driven machine
having a ram that reduces the volume of waste
material by subjecting it to pressure and forcing
it into a removable container or package.

Reg Abbr. for "regular."

REG l.On drawings, abbr. for register. 2. On
drawings, abbr. for "regulator."

Regency Revival A mode of Revival architec-
ture, found to a limited extent in America in the
1930s, that borrowed features of its Georgian and
Regency style prototypes; usually two stories
high with a hipped roof; had brick walls with
quoins at the corners and sometimes at the main
entrance, often painted white; double-hung win-
dows with shutters; an entrance porch; and, typi-
cally, a small octagonal window above the door.

804

reinforced column

Regence style The decorative and elegant
Rococo style flourishing under the regency of
Philip of Orleans (1715-1723) during the
minority of Louis XV.

Regency style The colorful neoclassic style,
often combined with oriental motifs, prevalent
in England between 1811 and 1830, during the
Regency and reign of George IV. Later, very
occasionally emulated in America as Regency
Revival; often combined with oriental motifs.

regenerative heating Heating by the use of
heat which is rejected in one part of the cycle
and utilized in another part of the cycle, by heat
transfer.

regia On the ancient Roman theater stage, the
central door, leading to the palace of the main
hero; the royal door.

register 1 . A grille having a damper, 1 for regu-
lating the quantity of air passing through it. 2. A
list of buildings, constructions, objects, or sites
that are of historic local, state, provincial, or
national interest. Such lists are maintained by
designated governmental agencies.

supply register

registered architect Same as architect, 2.

regie A groove or channel by which the move-
ment of anything, as that of a sliding or lifting
door or sash, is guided.

reglet l.A fillet or small flat-faced projection,
as used in a fret molding or to cover a joint
between two boards. 2. A raggle.

regrating The cleaning of masonry by remov-
ing a thin surface layer, exposing fresh stone.

regressed luminaire A luminaire which is
mounted above the ceiling with its opening
above the ceiling line.

regula In the Doric entablature, one of a series
of short fillets beneath the taenia, each corre-
sponding to a triglyph above.

regular coursed rubble Same as coursed
ashlar.

regulated-set cement A hydraulic portland
cement which contains an additive to control its
set and early strength.

regulating valve A valve that regulates or
closes off the flow of a fluid.

regulation Any rule prescribing permitted or
forbidden conduct, whether established by legis-
lation or the action of an administrative agency;
also see building code.

regulator In a gas supply system, a device for
controlling and maintaining a uniform gas sup-
ply pressure.

regulus metal See antimonial lead.

rehabilitation The process of returning a
building to its original state of utility by means
of repair or alteration.

reheat coil 1 . In an air-conditioning system, a
coil which heats air in the supply duct to control
its temperature. 2. A coil which is heated to
control the temperature of air being furnished to
individual zones, 1.

reheating In an air-conditioning system, the
heating of air which has already been condi-
tioned, e.g., the heating of air supplied to one
zone of the system in order to maintain temper-
ature control in that zone.

reimbursable expenses Amounts expended
for or on account of the project which, in accor-
dance with the terms of the appropriate agree-
ment, are to be reimbursed by the owner.

REINF On drawings, abbr. for "reinforce" or
"reinforcing."

reinforced bitumen felt A light roofing felt
saturated with bitumen and reinforced with a
jute cloth.

reinforced blockwork In masonry, block-
work in which steel reinforcement is added to
resist tensile, compressive, or shear stresses.

reinforced brick masonry See reinforced-
grouted brick masonry.

reinforced brickwork Any joints in brick-
work that are given extra strength, usually by
metal bars, mesh, rods, or wires across the joints.

reinforced cames Lead bars reinforced with a
steel core; used in leaded lights.

reinforced column A concrete column con-
taining reinforcement such as steel rods or wire
mesh.

805

reinforced concrete

reinforced concrete, beton arme, ferrocon-
crete, steel concrete Concrete containing
reinforcement designed on the assumption that
the concrete and reinforcement act together in
resisting forces.

reinforced concrete joint A concrete joint
that is bridged by reinforced steel embedded in
both sides of the joint.

reinforced concrete masonry Concrete
masonry construction in which steel reinforce-
ment (in excess of a specified minimum percent-
age) is so embedded that the materials act
together in resisting forces. Where hollow con-
crete masonry units are used, certain cores
(including those containing the embedded
reinforcement) are filled solidly with grout. In
multiwithe construction in which the reinforce-
ment is embedded between the withes, the space
between the withes is filled solidly with grout.

reinforced-grouted brick masonry, rein-
forced brick masonry Grouted brick
masonry in which reinforcement is provided in
the horizontal joints and in grouted vertical
joints between withes.

reinforced masonry Masonry units in which
reinforcement, usually steel mesh or rods, is
embedded in such a manner that the two mate-
rials act together in resisting forces.

reinforced membrane A roofing or water-
proofing membrane which is reinforced with
felts, mats, fabrics, fibers, or the like.

reinforced plastic A plastic having imbedded
high-strength fillers to provide mechanical
properties which are superior to those of the base
material.

reinforced T-beam A concrete T-beam that
has been reinforced with steel rod before the
concrete is poured.

reinforcement 1. In reinforced concrete, metal
bars, rods, wires, or other slender members
which are embedded in concrete in such a man-
ner that the metal and the concrete act together
in resisting forces. 2. Material added to provide
additional strength.

reinforcement displacement The move-
ment of steel reinforcement in the forms from its
specified position.

reinforcement ratio At any section of a rein-
forced concrete structural member, the ratio of

reinforcement, 1

the effective area of the reinforcement to the
effective area of the concrete.

reinforcement schedule Same as bending
schedule.

reinforcement weld Along a groove weld,
weld metal in excess of the specified weld size.

reinforcing arch An arch that reinforces a
tunnel vault.

reinforcing bar A steel bar used in concrete
construction (e.g., in a beam or wall) to provide
additional strength; also see deformed bar, rein-
forcing rod.

^^^^^^^S)

DEFORMED

reinforcing bars

reinforcing plate An extra plate used to rein-
force or strengthen a member.

reinforcing rod Any of a variety of steel rods
used in reinforced concrete.

reinforcing tape A high-strength tape which
resists stretching, wrinkling, and tearing; lies flat
and may be lightly sanded; may be used to add
strength and crack resistance along flat joints
and inside corners.

reinforcing unit In a metal door, a box-shaped
reinforcement in which a bored lock is installed;

806

relief map

SBHSJ^^fefe

reinforcing rods in place for a footing

provides support for the latch, both vertically
and horizontally.

reja In Spanish architecture and its derivatives,
a grille or grating over windows facing the street,
often projecting from the face of a house into
the street.

rejoin ting Same as repointing, 3.

relamp To replace one or more electric bulbs in
a lighting system.

relamping See spot relamping and group
relamping.

related trades In building construction, trades
whose work is required to complete a system
within a building (such as a HVAC system), part
of a building, or the entire project; or trades
using similar tools.

relative compaction The dry density of soil
in the field expressed as a percentage of the den-
sity of the soil after it has been subjected to a
standard amount of compaction.

relative consistency Of a soil, the ratio of the
liquid limit minus the natural water content to
the plasticity index.

relative density For a given void ratio of soil,
the ratio between: (a) the difference between the
void ratio of the soil in its loosest state and the
given ratio and (b) the void ratio in the loosest
state minus the void ratio in the densest state.

relative humidity The ratio of the weight of
water vapor actually in humid air to the maxi-
mum possible weight of the water vapor that the
air could contain at the same temperature; usu-
ally expressed as a percentage.

relative settlement See differential settlement.

relaxation of steel 1 . The decrease in stress in
steel as a result of creep within the steel under
prolonged strain. 2. The decrease in stress in
steel as a result of decreased strain of the steel,
such as results from shrinkage and creep of the
concrete in a prestressed concrete unit.

relay An electromechanical device in which
changes in the current flow in one circuit (that
flows through the device) are used to open or
close electric contacts in a second circuit.

release agent In formwork, any material that
is used to prevent the bonding of concrete to a
surface.

release of lien Instrument executed by one
supplying labor, materials, or professional ser-
vices on a project which releases his mechanic's
lien against the project property. Also see
mechanic's lien.

release paper A protective sheet having an
adhesive film on one side; may be easily removed
from the surface to which it is applied.

relief Sculptured work, carving, casting, or
embossing that is raised above the plane of its
background. Also called relievo; see bas-relief,
demi-relief, high relief, mezzo-relievo, sunk relief.

elief

relief cut A preliminary cut with a jig saw or
band saw to prevent the saw from binding, when
cutting a curve in a piece of wood.

relief damper, relief opening A damper in
an air-conditioning system which opens auto-
matically, relieving the buildup of air pressure
within the building or air-conditioned space.

relief grille See relief damper and relief opening.

relief map, hypsometric map A map de-
picting the configuration of the earth's surface,
called the "relief," by means of contours, form
lines, hachures, shading, tinting, or relief models.

807

relief opening

relief opening See relief damper.

relief valve A valve installed in a system to
relieve pressure in excess of a preset limit by
discharging a portion of the contents of the
system.

015* UPt

relief valves

relief vent A branch from the vent stack, con-
nected to a horizontal branch between the first
fixture branch and the soil or waste stack, whose
primary function is to provide for circulation of air
between the vent stack and the soil or waste stack.

SOIL OR
WASTE STACK

VENT

HORIZONTAL
BRANCH ,

:~^

VENT

STACK

FIRST
FIXTURE

relief vent

relieve To lighten a color in order to reduce its

intensity.
relieved 'work Ornamentation done in relief.
relieving arch Same as discharging arch.

relievo Same as relief, 1.

relish In carpentry and joinery, the projection
or shoulder at the side of, or around, a tenon.

relocatable partition See demountable parti-
tion.

REM On drawings, abbr. for "removable."

remainder An interest in property that confers
a right to possession in someone other than the
grantor or his heirs upon the termination of a
prior interest, such as following the death of a
life tenant.

remodeling See alterations.

remoldability The ease with which freshly
mixed concrete responds to an effort to remold
it, as by jigging or by vibration, causing it to
reshape its mass around reinforcement and to
conform to the shape of the formwork.

remolded soil Soil that has had its natural
structure modified by manipulation.

remolding test A test to determine the
remoldability of concrete.

remote-control circuit An electric circuit that
controls another circuit which is at a distance.

remote-entry system An electrically-
controlled door lock that includes a means for
supervising its operation by some type of identi-
fication check, such as an intercommunication
system, closed circuit TV, or key-card reader.

remote station system An electronic fire
alarm system capable of notifying the fire depart-
ment when the system is activated by a fire.

removable mullion A door mullion which can

be removed temporarily from a doorframe to per-
mit large objects to be moved through the frame.

removable stop 1. A stop which is removable
to permit the installation of a glass pane, fixed
panel, or door. 2. A glazing bead, 2.

Renaissance architecture, Renaissance
Classical architecture The architectural
style developed in early 15 th cent. Italy during
the rebirth (rinascimento) of classical art and
learning. It succeeded the Gothic as the style
dominant in all of Europe after the mid- 16th
cent., and evolved through the Mannerist phase
into Baroque and in the early 17th cent, into
classicism. Initially characterized by the use of
the classical orders, round arches, and symmetri-
cal composition.

808

res

Renaissance Revival A term occasionally
used as a synonym for Italian Renaissance
Revival.

render l.To give a mechanical drawing, as in
elevation, a more or less complete indication of
shades and shadows; in ink, color, or other
media. 2. To apply plaster directly to brick-
work, stonework, tile, etc.; esp. to apply the first
coat.

render coat See scratch coat.

render, float, and set Three-coat plastering
executed directly on stone or brick.

render and set To apply two-coat plastering

directly on stone or brick walls.
rendered Said of any piece of wood that is split

rather than sawn.

rendered brickwork Brickwork which has
been coated with a facing of waterproof material.

rendering 1. Applying a coat of plaster
directly on an interior wall or stucco on an
exterior wall. 2. A perspective or elevation
drawing of a project or portion thereof with
artistic delineation of materials, shades, and
shadows.

rendering coat The first coat of plaster on
brickwork or stonework.

rendu An architectural rendering of a design

problem.
renovation The restoration of a building to its

almost new condition.

rent See lease.

rent lath Lath which has been split instead of
sawn.

rent pale A narrow wood strip, esp. of oak
which has been split instead of sawn.

REP. On drawings, abbr. for "repair."

repair Replacement or renewal (excluding addi-
tions) of any part of a building, structure, device,
or equipment with like or similar materials or
parts, for the purpose of maintenance of such
building, structure, device, or equipment.

repeating theodolite A theodolite so de-
signed that successive measures of an angle may
be accumulated on the graduated circle, and a
final reading of the circle made which represents
the sum of the repetitions.

REPL On drawings, abbr. for "replace."

replum In door construction of the ancients, an
upright rail (from sill to lintel) which divides a
doorframe in two parts; used with a door having
two leaves, which close against it.

repointing Same as pointing, 3.

repousse Raised in relief by embossing or by
beating on the underside with a hammer.

reprise In masonry, the return of a molding in
an internal angle.

REPRO On drawings, abbr. for "reproduce."

reproducible Said of a drawing, copy, or the
like, which is capable of being used as a master-
to-be in a reproduction process.

REQD On drawings, abbr. for "required."

request for information A formal request in
writing, from the contractor to the architect,
asking for information.

requisition See application for payment.

rere»arch Same as rear arch.

reredorter A privy behind a monastery or
convent.

reredos An ornamental screen or wall at the
back of an altar.

1 ■ y^mmmmmmmm

reredosse In an ancient hall, the open hearth
upon which a fire was lit, immediately under the
louver, 2.

res In the lumber industry, abbr. for "resawn."

809

resealing trap

reseating trap On a plumbing-fixture drain
pipe, a trap, 1 which is designed so that the
rate of flow at the end of a discharge from
the fixture seals the trap but does not cause
self-siphonage.

reservoir A receptacle or enclosed space for the
collection or retention of water, which is sup-
plied to it by natural springs, drainage, or artifi-
cial means.

reshoring A temporary vertical support for
forms or a completed structure, placed after the
original shoring support has been removed.

residence casement 1 . Any casement used in
residential construction. 2. A lightweight, rela-
tively low-cost, steel or aluminum casement
window.

resident engineer A person representing the
owner's interests at the project site during the
construction phase; a term frequently used on
projects in which a governmental agency is
involved. Also see owner's inspector.

residential-custodial care facility A build-
ing, or part thereof, used for the lodging or
boarding of four or more persons who are inca-
pable of self-care because of age or physical or
mental limitation.

residential occupancy Occupancy of a build-
ing in which sleeping accommodations are pro-
vided for normal residential purposes; includes
all buildings designed to provide sleeping
accommodations except those classified under
institutional occupancy.

resident inspector l.See owner's inspector.
2. See resident engineer.

residual deflection A deflection resulting
from an applied load which remains after the
removal of the load.

residual deformation The nonreversible
deformation that remains in hardened concrete
after a sustained load has been removed.

residual soil Soil formed in place by weather-
ing of the underlying mineral materials.

residual sound The composite sound from
many sources and many directions (near and far)
remaining when all uniquely identifiable dis-
crete sound sources are eliminated.

residual stress A stress that remains in an
unloaded member after it has been formed into a
finished product, such as that induced in steel

shapes by cold bending, cooling after rolling, or

welding.
residual tack See aftertack.
resilience The ability of a body that has been

subjected to an external force to recover its size

and shape, following deformation.

resilient channel In sound-insulating con-
struction, a fabricated metal strip having two
faces with flexible interconnection; used for
attaching gypsum board to studs or joists without
a solid connection so as to reduce the transmis-
sion of noise and vibration.

resilient clip In sound-insulating construction,
a flexible metal device for attaching gypsum
board or metal lath to studs or joists to reduce
transmission of noise and vibration.

resilient connector In a piping system, a flex-
ible connector which joins pipe to another pipe
that is subject to vibration or joins a pipe to a
pump; can be deformed and deflected without
leakage or rupture.

resilient floor A wood floor, laid on battens,
having the quality of springiness (e.g., a floor
supported by spring clips); especially used as a
dance floor, gymnasium floor, etc.

resilient flooring A manufactured interior
floor covering, in either tile or sheet form, which
is resilient.

resilient hanger l.See resilient clip and
resilient channel. 2. A hanger, 1 which incorpo-
rates a metal or elastomer spring, providing a
resilient method of attachment.

resin A nonvolatile solid or semisolid organic
material, usually of high molecular weight;
obtained as gum from certain trees or manufac-
tured synthetically; tends to flow when sub-
jected to heat or stress; soluble in most organic
solvents but not in water; the film-forming com-
ponent of a paint or varnish; used in making
plastics and adhesives.

resin»bonded Descriptive of timber which has
been glued with a synthetic resin.

resin chipboard A particleboard in which the

binder for the wood chips is a resin.

resin concrete Concrete in which an organic
polymer is used as the binder.

resin-emulsion paint A water paint consist-
ing of a water emulsion of an oil-modified alkyd

810

restricted list of bidders

resilient hanger, 2

or other resin; when dry, leaves a tough film of
resin.

resin-impregnated wood, resin-treated
■wood Wood whose fibers are impregnated
with synthetic resin to provide improved hard-
ness, moisture resistance, durability, etc.

resin pocket See pitch pocket.

resin streak See pitch streak.

resin-treated wood See resin-impregnated
wood, compregnated wood.

resistance See electrical resistance, thermal
resistance, etc.

resistance brazing A brazing process in which
the heat required is obtained from the resistance
to electric current in a circuit of which the work
is a part.

resistance welding A group of welding pro-
cesses in which coalescence is produced by the
heat obtained from resistance of the work to
the flow of electric current in a circuit of which
the work is a part, and by the application of
pressure.

resistivity See electrical resistivity.

resistor A device used in an electric circuit to

control the flow of current.
resorcinol adhesive An adhesive which is

water-soluble for a period of 2 to 4 hr, and then

insoluble and chemically resistant.
respond A support, usually a corbel or pilaster,

affixed to a wall to receive one end of an arch, a

groin, or a vault rib.

respond

responsible bidder See lowest responsible
bidder.

ressant, ressaut 1. Medieval name for ogee, 2.
2. A projection of any member or part from
another, such as a projecting portion of a mold-
ing. 3. A roll molding.

ressault See ressant.

restaurant A building (or part of a building)
or any place used as a place where meals or
sandwiches are prepared and/or served to its
clientele.

rest bend A right-angle fitting, 1 for a pipe with
an integral seat which may be mounted on a
support.

restoration See building restoration.

restricted list of bidders See invited bidders.

811

restriction

restriction On land, an encumbrance limiting
its use; usually imposed for community or mutual
protection.

restrictive covenant An agreement between
two or more individuals, incorporated within a
deed which stipulates how land may be used. The
constraints may include: the specific use to which
a property can be put, the location and dimensions
of fences, the setback of buildings from the street,
the size of yards, the type of architecture, the cost
of the house, etc. Racial and religious restrictions
on inhabitants are legally unenforceable.

restrictive specification A building specifi-
cation that limits the purchase of a product to a
specific manufacturer or to the purchase of a
material from a specific supplier.

restroom A public lavatory.

resurfacing The placing of a supplemental sur-
face on an existing surface to improve its confor-
mation or to increase its strength.

RET. On drawings, abbr. for "return."

retable A decorative screen set up above and
behind an altar, generally forming an architec-
tural frame to a picture, bas-relief, or mosaic.

retainage A sum withheld from progress pay-
ments to the contractor in accordance with the
terms of the owner-contractor agreement.

retaining wall A wall, either freestanding or
laterally braced, that bears against an earth or
other fill surface and resists lateral and other
forces from the material in contact with the side
of the wall, thereby preventing the mass from
sliding to a lower elevation. Also see cantilever
wall, counterfort wall, gravity wall.

retardation Reduction in the rate of hardening
or setting; an increase in the time required to

reach initial and final set or to develop early
strength of fresh concrete, mortar, plaster, or grout.

retard chamber A device in a fire sprinkler
system used to minimize false alarms caused by
surges or fluctuations in its water supply system.

retarded hemihydrate A calcined gypsum
plaster having a retarder added to control the
setting action.

retarder 1. In paint, varnish, or lacquer, a high-
boiling solvent used to lower evaporation rate of
the volatile ingredients. 2. An admixture which
delays the setting of cement paste or the setting
of mixtures such as mortar or concrete contain-
ing cement. 3. An additive, mixed with plaster
to control the rate of hardening.

retarding admixture Same as retarder, 3.

retemper To replace water that has been evap-
orated from a mortar mix.

retempering l.The addition of water and
remixing of concrete or mortar which has started
to stiffen. 2. The addition of a small amount of
water to plaster or mortar as it begins to set;
improves spread and workability, but weakens
the plaster.

retention 1 . The withholding of a portion (usu-
ally 10%) of a periodic payment to a contractor,
by prior agreement, for work completed. The
retention is held in escrow for a stipulated time
period after the acceptance of the completed
work by the architect and owner/payee. 2. The
amount of preservative, fire-retardant salt, resin,
etc., retained by treated or impregnated wood.

retention basin A depression for temporarily
storing storm water in order to reduce the rate of
runoff from a drainage area.

retention money Same as retention, 1.

retention wall A thin wall or barrier which
forms a gap between it and the external wall of a
building (the space between being filled with a
waterproofing material).

reticulata fenestra A lattice window pro-
tected by small bars of wood or metal that cross
each other in a net-like pattern.

reticulated Covered with netted lines; netted;
having distinct lines crossing in a network.

reticulated molding A molding decorated
with fillets interlaced to form a network or
mesh-like appearance.

812

return grille

reticulated masonry

reticulated molding

reticulated tracery Tracery whose openings

are repetitive like the meshes of a net.
reticulated work Same as opus reticulatum.
reticulatum opus Same as opus reticulatum.

reticuline bar Of a grating, a sinuously bent
connecting bar extending between two adjacent
bearing bars.

retractable roof A roof system, usually over an
auditorium, designed to roll back the roof on
tracks so that the interior of the facility is open
to the outdoors.

retrochoir A chapel behind the high altar of
a church but in front of the Lady chapel if there
is one.

retrofit The addition of new building materials,
building elements, and components, not provided
in the original construction. See building retrofit.

return The continuation of a molding, projec-
tion, member, or cornice, or the like, in a differ-
ent direction, usually at a right angle. For
example, see cornice return and label return.

return air Air returned from an air-condi-
tioned or refrigerated space to the central plant
for processing and recirculation.

return air fan A fan which withdraws air from
an air-conditioned space and returns it (or part
of it) to the central air-conditioning system.

return air grille Same as return grille.

return-air intake An opening through which
return air reenters an air-conditioning system;
usually provided with a damper to regulate the
flow of return air.

return bead The continuation of a bead in a

different direction, usually at a right angle. Also

see quirk bead.
return bend A pipe fitting, 1 or a preformed

piece of tubing which provides a 180° change in

direction.

return bend

return-circulation system See hot-water

recirculation system.
return duct A duct carrying return air.
returned cornice See cornice return.

returned end The end of a molding having a
shape which is the same as the profile of the
molding.

returned molding A molding continued in a
different direction from its main direction.

returned molding

returned stall See return stall.

return fan A fan that removes air from an air-
conditioned space.

return fill Same as backfill.

return grille A grille, 2 through which return
air is extracted; usually not provided with an
adjustment for volume of airflow.

return grille

813

return head

return head A stone quoin, at the corner of a
building, that has the same finish on both the
face and the side.

return mains Pipes or conduits which return a
heating or cooling medium from the heat trans-
fer unit to the source of heat or refrigeration.

return offset, jumpover In plumbing, a dou-
ble offset, 3 installed in a pipeline to pass around
an obstruction.

return offset

return period See average frequency of occur-
rence.

return pipe In a heating system, a pipe through
which water that is produced by the condensa-
tion of steam is returned to the boiler.

return stall A stall, 1 , in the chancel of a church,
facing the high altar; also called a returned stall.

return system l.An assembly of connected
ducts, or passages or plenums, and fittings through
which air from an air-conditioned space is deliv-
ered to the return fan. 2. In a piping system, the
pipes through which water is returned to a pump.

return wall A short wall usually perpendicular
to, and at the end of, a freestanding wall to
increase its structural stability.

REV On drawings, abbr. for "revise."

revale A stone molding, carved in place.

reveal 1 . The side of an opening for a door or win-
dow, doorway, or the like, between the doorframe
or window frame and the outer surface of the wall;
where the opening is not filled with the door or
window, the whole thickness of the wall. 2. The
distance from the face of a door to the face of the
frame on the pivot side.

reveal lining Moldings or any other finish
applied over a reveal.

reveal pin, reveal tie An adjustable clamp,
placed horizontally across an opening in a wall;
used to hold scaffolding against the wall.

revel Same as reveal.

revent pipe That part of a vent pipeline which
connects directly with an individual waste pipe
or group of waste pipes underneath or back of
the fixture, and extends to either the main or
branch vent pipe; also called an individual vent.

reverberation The persistence of sound in an
enclosed space (such as a room or auditorium)
after a source of sound has stopped.

reverberation chamber A room, having a
long reverberation time, which is especially
designed for the measurement of the sound
absorption coefficients of an acoustical material
or the sound power of a sound source.

reverberation time A measure of reverbera-
tion in an enclosed space; the time required for
sound-pressure level to decrease 60 dB after the
source has stopped.

reverse A template that has the reverse profile
of a molding it is intended to match.

reverse-acting diaphragm valve A valve
which opens when pressure is applied on a
diaphragm and closes when pressure is released.

reverse-acting thermostat An instrument
which activates a control circuit upon sensing a
predetermined high temperature.

reverse bevel A bevel on the latch bolt or lock
of a door, opening outward from a building, etc.,
which is the reverse of an ordinary lock bevel.

reversed door See reverse-swing door.

reversed loader A front-end loader on a
wheel tractor which has the driving wheels in
front and the steering wheels at the rear.

reversed zigzag molding A compound orna-
mental zigzag molding commonly used in Nor-
man architecture.

reversed zigzag molding

814

Rfg

reverse-flight stair See dogleg stair.

reverse-swing door, reversed door A door
which opens in a direction opposite the usual
direction; a door to a room which swings outward.

reversible grating A grating which is con-
structed so that it may be installed with either
side exposed, with no difference in appearance
or carrying capacity.

reversible lock A lock which, by reversing the
latch bolt, may be used either way; on certain
types of locks, other parts also must be changed.

reversible window A window in which the
sash may be turned so that the glass surface that
normally faces the exterior is turned toward the
interior for purposes of cleaning.

reversion Chemical reaction leading to the
deterioration of a sealant, backup, or filler; due
to moisture trapped behind the sealant.

revertible flue A flue or breeching designed so
that at some point in the travel of the flue gases
they are forced to flow downward instead of in
the normal upward direction.

revestry Old form of vestry.

revet To face a sloping wall or foundation, an
embankment, or the like, with stone, concrete,
or a similar material.

revetment l.Any facing of stone, metal, or
wood over a less attractive or less durable sub-
stance or construction. 2. A retaining wall or
breast wall; a facing on an embankment to pre-
vent erosion.

revibration One or more applications of vi-
bration to concrete after completion of placing
and initial compaction but preceding initial
setting.

revision A change made in the working draw-
ings and specifications for a building project sub-
sequent to the start of construction.

Revival architecture Architecture that makes
use of elements of an earlier style that it seeks to
emulate, borrowing many of the features of its
prototype, as described under the term architec-
tural mode. For example, see Adam Revival,
American Colonial Revival, American Renais-
sance Revival, Byzantine Revival, California
Mission Revival, Carpenter Gothic Revival, Cha-
teauesque Revival, Classical Revival style, Classic
Revival, Colonial Revival, Dutch Colonial Re-
vival, Early Classical Revival, Early Gothic Re-

vival, Early Romanesque Revival, Egyptian
Revival, Exotic Revival, Federal Revival, French
Revival, Georgian Revival, Gothic Revival,
Greek Revival style, International Revival, Italian
Renaissance Revival, Jacobethan Revival, Late
Gothic Revival, Mediterranean Revival, Mission
Revival, Monterey Revival, Moorish Revival,
Neoclassical Revival, Neoclassical style, Neoclas-
sicism, Neo-Colonial, Neo-Eclectic, Neo-French,
Neo-Georgian, Neo-Gothic, Neo-Grec, Neo-
Greek Revival, Neo-Romanesque, Neo-Tudor,
Neo-Victorian, Oriental Revival, Period Revival,
Pueblo Revival, Regency Revival, Renaissance
Revival, Romanesque Revival, Second Renais-
sance Revival, Spanish Colonial Revival, Spanish
Pueblo Revival, Territorial Revival, Tudor Re-
vival, Tuscan Revival.

revolving-blade mixer Same as open-top
mixer.

revolving door An exterior door consisting of
four leaves (at 90° to each other) which pivot
about a common vertical axis within a cylindri-
cally shaped vestibule; prevents the direct pas-
sage of air through the vestibule, thereby
eliminating drafts from outside.

revolving door: plan

revolving-drum truck mixer A truck which
mixes concrete during its transport to a construc-
tion site. Previously proportioned materials from
a batch plant are transferred to the truck drum
where all mixing takes place.

revolving shelf See lazy susan.

revolving shovel A shovel in which the dig-
ging machinery can rotate independently from
the supporting structure.

rez-de-chaussee The ground floor of a building.

RF On drawings, abbr. for roof.

Rfg Abbr. for "roofing."

815

RFP

RFP Abbr. for "request for proposal."

rgh, Rgh In the lumber industry, abbr. for
"rough."

Rh Abbr. for Rockwell hardness.

RH l.Abbr. for relative humidity. 2. Abbr. for
"right hand." 3. Abbr. for "round head."

Rhenish brick A type of lightweight brick.

rheology The science dealing with flow of mate-
rials, including studies of deformation of hard-
ened concrete, the handling and placing of
freshly mixed concrete, and the behavior of slur-
ries, pastes, and the like.

rheostat An electric device having a resistance
which can be adjusted; used to control the flow
of electric current, as, for example, in one type of
dimmer.

RHN Abbr. for Rockwell hardness number.

rib l.A curved structural member supporting
any curved shape or panel. 2. In vaulted roofs,
the moldings which project from the surface and
separate the various roof or ceiling panels. 3. A
raised ridge or fold which is formed in sheet
metal (or a formed section attached thereto) to
provide stiffness.

•ib, 1 of

or an arcrt

ribs, 2 dividing a ceiling into squares

RIB A Abbr. for Royal Institute of British Archi-
tects.
riband, ribband Same as ribbon strip.

ribbed arch An arch composed of individual

curved members or ribs.
ribbed fluting 1. (Brit.) Flutes alternating with

fillets. 2. See cabled fluting.

ribbed panel A reinforced concrete panel com-
posed of a thin slab reinforced by a system of ribs.

ribbed slab Same as ribbed panel.

ribbed vault A vault in which the ribs support,
or seem to support, the web of the vault.

ribbed vault

ribbing An assemblage or arrangement of ribs,
as timberwork sustaining a vaulted ceiling.

ribbing up Laminating circular joinery by gluing
up layers of veneer with parallel grain direction.

ribbon 1. A ribbon strip. 2. A long thin strip of
wood, or a series of such strips uniting several
parts. 3. In stained glass work or the like, a strip
or bar of lead to hold the edge of the glass. Also
called a came.

ribbon board l.A ribbon strip. 2. A horizon-
tal member in formwork used to prevent the
spreading of a wall box.

JOISTS

RIBBON
BOARD

STUDS

ribbon board, 1

ribbon course A course in roofing, in which
the exposed depth of tile, slate, etc., from one
course to the next is alternately large and small.

ribbon development An urban extension pri-
marily in the form of a single depth of buildings
along roads radiating from a city, along a highway
between two cities, or along the bank of a river.

816

ridgeboard

ribbon loading In batching concrete, the
loading of all the solid ingredients (and some-
times water) into the mixer at the same time.

ribbon rail A metal rail which joins the tops of
metal balusters.

ribbon saw Same as band saw.

ribbon strip, girt strip, ledger board, rib-
and, ribband A wood strip or board let into
the studs to add support for the ends of the joists;
also called a girt strip or ledger board.

ribbon-stripe veneer, ribbon-grained ve-
neer, stripe veneer Wood veneer having
alternate light and dark stripes running parallel
to the grain. Also see interlocked grain.

ribbon window, ribbon lights On the
facade of a building, a horizontal band of at least
three windows, separated only by mullions;
occasionally called a window band.

ribbon wall Same as serpentine wall.

rib lath, stiffened expanded metal Ex-
panded-metal lath having V-shaped ribs to pro-
vide greater stiffness and to permit wider spacing
of framing members.

rib vault Same as ribbed vault.

Richardsonian Romanesque style, Roman-
esque Revival The massive architectural
style, from 1880 to 1900 and beyond, as prac-
ticed by Henry Hobson Richardson (1838-1886)
and his followers; an outgrowth of earlier archi-
tecture making use of architectural elements of
the Romanesque style, chiefly in public build-
ings, churches, railroad terminals, and universi-
ties designed from 1840 to 1880. Buildings in

Richardsonian Romanesque

this style usually exhibit many of the following
characteristics: a facade of rough-cut rock-faced
masonry, and different colors and textures of
stone, occasionally in combination with decora-
tive brickwork; massive semicircular arches,
sometimes in combination with flat arches; clus-
tered arches or piers; a decorative tympanum;
parapeted gable ends; short, thick columns,
occasionally with cushion capitals; bands of
engaged colonettes; decorative plaques; a roof
covering of slate or tile; one or more cross gables;
decorative cresting or decorative tile at the ridge
of the roof; a tower with a steep roof and/or
topped with a finial; a steeply pitched, hipped
roof with little roof overhang at the eaves; a dec-
orative chimney; double-hung windows, often
arched or rectangular; deeply recessed window
opening; window openings framed by round
arches having hooded moldings, often with label
stops; often, a circular or semicircular window in
a wall gable; doors usually deeply set within mas-
sive semicircular or segmental masonry arches
ornamented with Romanesque decorations.
Also called Neo-Romanesque or Romanesque
Revival. See Victorian Romanesque.

rich concrete Concrete having a high cement
content.

rich lime A fat lime.

rich low brass See red brass.

rich mix A fat mix.

rich mixture Same as fat mix.

rich mortar A fat mortar.

RICS (Brit.) Abbr. for Royal Institution of

Chartered Surveyors.
riddle A sieve, esp. a coarse one for sand.
rider cap Same as pile cap.
rider shore A heavy timber whose lower end

abuts another timber laid against the back of the

outer raking shore rather than against the ground.
ridge l.The horizontal line at the junction of

the upper edges of two sloping roof surfaces. 2.

The internal angle or nook of a vault.
ridge batten Same as ridge roll.
ridge beam A beam at the upper ends of the

rafters, below the ridge of a roof; a crown plate, 2.

(See illustration p . 818.)

ridgeboard, ridgepole A longitudinal mem-
ber at the apex of a roof which supports the

817

ridgecap

RIDGE
BEAM

ridge beam

BOARD

ridgeboard

upper ends of the rafters. Also called a ridge
beam, ridgepiece, ridgeplate, or ridgetree.
ridgecap, ridge capping, ridge covering

Any covering (such as metal, wood, shingle,
etc.) used to cover the ridge of a roof.

ridgecap

ridge course The last or top course of roofing

tiles, roll roofing, or shingles.
ridge covering See ridgecap.
ridge crest The ornamentation of the ridge of a

roof.
ridge cresting See cresting.

ridge cut See plumb cut.

ridge fillet A fillet between two depressions, as
between two flutes of a column.

ridge molding A molding of sheet metal, cop-
per, zinc, or lead which covers the ridge of
a roof.

ridge plate A heavy timber, often square in sec-
tion, that is set directly below the ridge of a roof.

ridgepole See ridgeboard.

ridge purlin l.Same as ridgeboard. 2. A
purlin, placed at the apex of a roof, which rests
against the upper ends of the rafters.

ridge rib 1 . A horizontal rib marking the crown
of a compartment of vaulting, characteristic of
English Gothic architecture from the early 13 th
cent, on, but occasionally found on the Conti-
nent. 2. A rib which follows the ridge of a vault.

ridge roll l.A wood strip, rounded on top,
which is used to finish the ridge of a roof; often
covered with lead sheeting. 2. A metal, tile, or
asbestos-cement covering which caps the ridge
of a roof; also called a hip roll or ridgecap.

ridge roll

ridge roof A pitched roof; the rafters meet at
the apex of a ridge; the end view is that of a
gable roof.

ridge stop In roofing, a metal flashing used at
the intersection of a ridge and a wall rising
above it.

ridge terrace On a slope, the area behind a con-
tour line of a slope which forms a ridge that retains
the rainwater that falls on the slope above it.

ridge tile, crown tile A tile which is curved
in section, often decorative, used to cover the
ridge of a roof.

ridgetree An archaic form of ridgepole.

ridge ventilator A roof ventilator that strad-
dles a ridge of the roof of a barn; usually square in
plan and constructed of wood and/or metal.

818

right-of-way

ridge tile

ridging l.In built-up roofing, a failure charac-
terized by long narrow blisters in the roof sur-
face. 2. The covering of the ridge of a roof.

riding house A structure especially designed
for teaching the skill of horse riding.

riding house

riding shore Same as rider shore.

riding trail See bridle path.

riebeckite asbestos A type of mineral derived
from a monoclinic amphibole.

riffler A file which is curved and grooved for
working in depressions.

rifle hole A slot in an exterior wall of struc-
tures such as blockhouses, forts, and garrison
houses, used for defensive purposes. The sides of
the slot are splayed so the opening is wider at
the inner face of the wall than at the exterior

rifle holes in a blockhouse

face, permitting a rifleman on the interior to
fire over a wide angle.
rift The direction in which stone splits most
readily; characteristic of granite or other stone
not having visible stratification or foliation.

rift-grained See edge-grained.

rift sawn See quartersawn.

rigger A long-haired, slender brush used in pre-
cision painting.

rigging See stage rigging.

rigging line A rope or wire used in stage
rigging.

rigging loft A space above the stage of a legiti-
mate theater; designed and used for the flying
and storage of scenery and scenic elements.

riggot An open rainwater drain, such as a gutter.

right angle An angle of 90°.

right-hand door See hand.

right-hand lock A lock for use on a right-
hand door.

right-hand reverse door See hand.

right-hand stairway A stairway having the
rail on the right side, in the ascending direction.

right line A straight line between two points.

right-of-way Any strip or area of land, includ-
ing surface and overhead or underground space,
which is granted by deed or easement for the
construction and maintenance of specified

819

rigid arch

linear elements such as power and telephone
lines; roadways; gas, oil, water, and other
pipelines; sewers.

rigid arch An arch which has no joints, being
continuous and rigidly fixed at the abutments.

rigid bent A frame structure that is moment-
resisting, i.e., is rigid in two dimensions.

rigid concrete pavement Reinforced port-
land concrete pavement on a gravel base and
subbase; usually has transverse joints for control-
ling expansion and contraction.

rigid connection A connection between two
structural members which prevents one from
rotating with respect to the other.

rigid dampproof course Slate or brick that
serves as a dampproof course.

rigid foam 1 . See cellular plastic. 2. See foamed
plastic, 1.

rigid frame A structural framework in which
all columns and beams are rigidly connected;
there are no hinged joints and the angular rela-
tionship between beam and column members
are maintained under load.

rigid insulation Thermal insulation whose
density is high enough so that a sheet of this
insulation will stand upright if supported only
along one edge of the sheet.

rigid insulation board See hardboard.

rigid joint A joint between structural members
which does not permit relative motion between
them.

rigidity That property of a material which
resists a change in its physical shape.

rigidized Said of light-gauge sheet metal which
is embossed or textured by a rolling process to
provide additional stiffness.

rigid lock See preassembled lock.

rigid metal conduit A raceway for electric
wires or cables, made of metal pipe of standard
thickness and weight permitting the cutting of
standard threads.

rigid pavement A pavement which provides
high bending resistance and which distributes
loads to the foundation over a relatively large area.

riglet Same as reglet.

rim l.The border or outer edge of anything
which is circular or continuously curved. 2.
Descriptive of any finish hardware which is

designed for application to the face of a door or

window, rather than for mortising.
rim joist, rim board A piece of wood, around

the perimeter of a wood frame, to which the

ends of floor joists are attached.
rim latch A surface-mounted latch.
rim lock A face-mounted door lock. Compare

with box lock.
rinceau In classical architecture and deriva-
tives, an ornamental band of undulant and

recurving plant motifs.

rind gall A defect in timber caused by a bruise
in the bark which produces a callus on the wood
over which later layers grow without consoli-
dating.

ring cairn A pile of stones, set in a circle, with
an open central space.

ring course In an arch, an outer course of stone
or brick.

ringed column See banded column.

ringing chamber A room in the lower part of
a church tower where the ropes that ring the
church bells are located.

Ringelmann chart A chart used as the basis for
evaluating the density of smoke discharged from
chimneys.

ring gasket Same as gasket, 2.

ring-groove nail Same as ring-shank nail.

ringhiera In Italian Medieval architecture, a
balcony (on the front of the town hall) from
which speeches and decrees were read.

ringlock nail Same as ring-shank nail.

ring louver, (Brit.) spill ring In lighting, a
louver system in the form of concentric annu-
lar rings; used in luminaires having circular
apertures.

820

rise and run

ring-porous wood Hardwood having spring-
wood pores which are larger and more distinct
than those produced later in the growing season.

ring scratch awl A scratch awl esp. used in
sheet-metal fabrication.

ring shake, cup shake, shell shake, wind
shake A separation in wood between or
along the annual rings.

ring-shank nail A nail having a number of
ring-like grooves around the shank to increase
its holding power.

ring stone One of the stones of an arch which
show on the face of the wall, or the end of the
arch; one of the voussoirs of the face forming the
archivolt.

ring-type hanger A type of hanger primarily
used to support pipes; either fabricated in one
piece or split in two halves which are fastened.

ringwork In medieval times, one or more defen-
sive ditches or banks (usually more or less circu-
lar or oval in shape) to protect the area within.

rink 1 . A bounded space of ice, usually enclosed,
for skating, curling, or ice hockey matches. 2. A
bounded space, usually enclosed, with a smooth
floor, of wood or asphalt, for roller skating.

rip To cut wood lengthwise, parallel to the grain.

riparian right The right of a landowner to use
water from a river or other body of water on
which his land abuts.

ripper 1 . An attachment with long angled teeth
that fits on the rear of a tractor or is towed by it;
penetrates and loosens subsurface layers of earth
to a depth of up to 3 ft (approx. 1 m). 2. A tool
used for removing damaged slates on a roof;
consists of a long steel blade with a notched
hook at one end for withdrawing nails. 3. A
towed machine, provided with teeth to loosen
hard soil and soft rock.

ripping See ripsawing.
ripping bar Same as pinch bar.

ripping chisel In woodworking, a bent chisel
used in clearing out mortises or seams.

ripping size The size of lumber, as it comes
from the operation of ripsawing, that is required
to obtain a specified finish size.

ripple figure Same as fiddleback or curl.

ripple finish A crackled or wrinkled paint finish,
usually obtained by baking. Also see wrinkling.

riprap 1 . Irregularly broken and random-sized
large pieces of quarry rock; individual stones rang-
ing from very large (2 to 3 cu yd, approx. 1.5 to
2.3 cu m) to small (Vi cu ft, approx. 0.014 cu m);
used for foundations and revetments. 2. A foun-
dation or parapet of stones thrown together with-
out any attempt at regular structural arrangement.

ripsaw A saw, the teeth of which have a chisel-
like ripping action; used for cutting wood in the
direction of the grain.

TOP VIEW OF RIP TEETH

TEETH OF RIP SAW

ripper, 1

ripsaw

ripsawing, flat cutting, ripping Sawing
lumber parallel to the grain direction.

rise 1. The height of a flight of stairs from land-
ing to landing. 2. The height between successive
treads of a stair. 3. The vertical distance such as
that used to express the height of a roof slope
compared to horizontal distance or run, or the
vertical measurement from the face of one stair
tread to the next. 4. In an arch, the vertical dis-
tance from the springing line to the highest
point of the intrados. 5. Of elevators, same as
travel.

rise-and-fall table A circular-saw assembly
in which the table, rather than the saw, is mov-
able.

rise and run l.The pitch of an inclined sur-
face or member, usually expressed as the ratio of

821

risen molding

the vertical rise to the horizontal run. 2. The
slope of a building element expressed as the ver-
tical increase in height for a selected distance in
the horizontal direction.

risen molding Same as bolection molding.

riser l.The vertical face of a stair step. 2. Any
upright face, as of a seat, platform, etc. 3. A plat-
form on the stage of a theater or concert hall
on which a performer is placed. 4. A water-
supply, drainage, gas, steam, or vent pipe which
extends vertically, one full story or more, to ser-
vice several branches or a group of fixtures.
5. An electrical cable which extends vertically,
one full story or more, to distribute electrical
power to electric panels on the different floors of
a building. 6. A duct, which extends vertically,
one full story or more, to distribute air
to branch ducts on the different floors of a build-
ing. 7. A vertical supply pipe for a fire sprinkler
system.

RISER

riser, 1

riser board In formwork, the board that forms
the vertical face of a step.

riser diagram A diagram (two-dimensional, in a
vertical plane) which shows the major items of
electrical equipment in a building; displays, floor
by floor, the feeders and major items of equipment.

riser height The vertical distance between the

top surfaces of two successive treads.
riser pipe A riser, 4.

rising arch An arch having a springing line
which is not horizontal.

rising damp The upward movement of mois-
ture in a wall or other structure standing in wet
soil or water.

rising hinge, rising butt hinge A door hinge
having a spiral groove winding about its knuckle,
or having the joints of the knuckle oblique, so
that when opened, the door is lifted and clears
the carpet.

rising main Same as riser, 4 or riser, 5.

risk management In the building industry,
the systemized practice of avoiding potential
risks, such as culpability and liability or legal
entanglements.

rive To split wood along the grain, as in making
shingles.

rived board, riven board A board that has
been shaped by splitting it along the grain
instead of sawing it.

riveling See wrinkling.

riven laths Wood laths made by splitting

instead of sawing.
riven slate A slate that is cleaved along one of

its parallel planes.

rivet A short pin, of a malleable metal such as
iron, steel, or copper, with a head at one end;
used to unite two metal plates by passing it
through a hole in both plates and then hammer-
ing down the point to form a second head.

COUNTERSUNK, COUNTERSUNK. BUTTON,
RAISED FLAT CDNEO NECK

BUTTON, PAN, PAN,

STRAIGHT NECK CONED NECK STRAIGHT NECK

rivet heads

rivet centers The distance between the cen-
ters of rivets along a straight line, as along a
bearing bar in a riveted grating.

riveted grating A grating composed of
straight bearing bars and bent connecting bars,
which are joined at their contact points by
riveting.

riveted joint A connection between two mem-
bers which are riveted together.

n;>>

rock rash

riveted truss Any truss having its main mem-
bers riveted together.

rivet hole A hole through which a rivet is driven.

riveting The fastening of plates or parts by
means of rivets.

riveting hammer A hammer having a long
head, a flat face, and a narrow peen; used for
swaging down rivets or beating sheet metal.

rivet set, rivet snap, setting punch, snap
A tool for shaping the head of a rivet.

rivet snap See rivet set.

riving knife, froe, frow A tool for splitting
shingles and the like.

R/L Abbr. for "random lengths."

R lamp A reflector lamp (usually incandescent)
having a thin glass envelope, the back interior
side of which is aluminum-coated to serve as a
light reflector; this reflecting surface is shaped so
as to provide a desired beam spread.

RM On drawings, abbr. for room.

rms Abbr. for "root mean square."

road breaker Same as concrete breaker.

road oil A heavy petroleum oil, usually one of
the grades of slow-curing asphalt.

rocaille An ornament, usually asymmetrical,
consisting of rock, plant, and shell forms in com-
bination with artificial forms; widely used during
the 1 8th century when Rococo was popular.

rock 1. Solid natural mineral material, occur-
ring in fragments or large masses and requiring
mechanical or explosive techniques for removal.
2. Stone in a mass. 3. A stone of any size.

rock asphalt Porous rock such as sandstone or
limestone that has become impregnated with
natural asphalt through a geological process.

rock»cut Said of a temple or tomb excavated
in native rock without the aid of masonry, or
with but little masonry; usually presents an

rock-cut tomb at Telmissus

architectural front with dark interior chambers,
of which sections are supported by masses of
stone left in the form of solid pillars.

rock dash An exterior stucco finish containing
crushed rock, large pebbles, or shells that are
imbedded in a stucco base; also called pebble
dash or slap dash.

rock drill A machine or device for drilling a
hole in rock so that it may be blasted; usually
driven by compressed air, but also may be driven
by electricity or by steam.

rocket tester Same as smoke rocket.

rock»faced A term descriptive of the rough
face of stone as it is split at the quarry or dressed
to resemble such a natural face; squared off only
along the edges.

rock-faced finish Same as natural cleft finish.

rock fill A fill, 1 comprised of large, loosely
placed rocks.

rock flour A very finely powdered rock mate-
rial; also see silt.

rocking frame A flat mechanically powered,
oscillating bed; used to compact concrete, which
is in the plastic state, in precast units temporar-
ily set on the bed.

rock lath See gypsum lath.

rock pocket A porous, mortar-deficient por-
tion of hardened concrete; consists primarily of
coarse aggregate and open voids; results from the
leakage of mortar from the concrete form, sepa-
ration (segregation) during placement, or insuf-
ficient consolidation.

rock rash A patchwork applique of oddly
shaped stone slabs; used on edge as a veneer;
often further embellished with cobbles or geodes.

823

Rockwell hardness

Rockwell hardness A measure of the resis-
tance of a material to indentation; determined
by use of a machine which presses a steel ball or
a spheroconical ball indentor into the material
under arbitrarily fixed test conditions; expressed
by the Rockwell hardness number — the higher
the number, the harder the material.

Rockwell hardness tester

Rockwell hardness number A measure of
Rockwell hardness; determined by use of a
machine having an indentor which can be
loaded; the number is derived from the net
increase in depth of impression that the indentor
makes in the material as the load on the inden-
tor is increased from a fixed load to a higher load,
and then returned to the minimum load.

rock storage The storage of heat in a large
mass of rocks, collected by a solar energy system
during the hours of maximum solar absorption
for use later, when required.

rock wool A type of mineral wool made by
forming fibers from molten rock; used in thermal
insulation.

rockwork 1. Quarry-faced masonry. 2. Stone-
work in which the surface is left irregular and
rough.

Rococo A style of architecture and decoration,
primarily French in origin, which represents the
final phase of the Baroque around the middle of
the 18th cent.; characterized by profuse, often
semiabstract ornamentation and lightness of
color and weight.

Rococo

rod l.In plastering, a straightedge, usually of
wood, for leveling the face of a wall. 2. A solid
(metal, wood, or plastic) product that is long in
relation to its cross section. 3. A leveling rod.

rod bender A powered device, with movable
rollers and clamps, used to bend steel reinforcing
rods to shapes required in reinforced concrete.

rod cutter A bench-type device, with a guillo-
tine-like wedge, used to cut steel reinforcing rods.

roddability The susceptibility of fresh concrete
or mortar to compaction by means of a tamping
rod.

rodded joint A masonry term occasionally
used for a concave joint.

rodding 1 . The strengthening of stone slabs or
panels (usually marble) by cementing reinforc-
ing rods into routings in the back. 2. The con-
solidation of mortar or concrete by the repeated
insertions and withdrawals of a rod. 3. The
clearing of an obstruction in a drain.

rodding eye Same as cleanout.

rode A medieval English form of rood.

rod level An accessory for use with a leveling
rod or a stadia rod to assure a vertical position of
the rod prior to instrument reading.

rod target A target carried on a leveling rod or
a range rod and upon which sights are made in
surveying.

roe figure A type of grain in wood; esp. found
in tropical woods with a spiral grain which have
been quarter-sawn.

roll 1. A rounded strip fastened to, and running
along, the ridge of a roof. 2. In a roof covered

sit

rolling shutters

rod target

with sheet metal, one of a number of rounded
strips placed under the metal sheeting at inter-
vals, to prevent movement of the sheets result-
ing from expansion and contraction. 3. Any
type of rounded molding. 4. A quantity of any
material wound in cylindrical form.
roll-and-fillet molding A molding of nearly
circular cross section with a narrow band or fillet
on its face.

roll flashing A type of flashing in the form of a
roll of a thin, impermeable, nonrustable material.
rolled steel beam See rolled beam.

rolled strip roofing See asphalt prepared
roofing.

roller l.See paint roller. 2. A self-propelled or
towed device to compact soil.

roller coating 1. Applying a coat of paint with
a paint roller. 2. A method of paint application
whereby an object is coated between two rollers
wet with paint.

roller-coating enamel An enamel made esp.
for application on strip steel, aluminum, or other
metal surfaces, using a roller-coating machine.

roller door Same as roll-up door.

roller latch A type of door latch; has a roller
under spring tension instead of a beveled spring
bolt; the roller engages a strike plate having a
recess formed to receive it.

roll-and-fillet molding

roll billet molding A common Norman mold-
ing consisting of a series of billets, 1 which are
cylindrical in cross section, usually staggered in
alternate rows.

roll billet molding

roll capped Said of ridge tiles having a roll
along the apex.

rolled Said of metal which has been shaped,
either hot or cold, by being passed between rollers.

rolled beam, rolled steel beam A metal
beam fabricated of steel made in a rolling mill.

rolled glass A flat glass sheet produced by passing
a stream of molten glass between two steel rollers;
usually in widths up to 12 ft (3.66 m) and thick-
nesses from Va to 1 in. (3.2 to 31.8 mm). Embossed
rollers are used to produce patterned surfaces.

roller latch

roller strike A strike plate which has a cylin-
drical roller at the point where the latch bolt of
a lock makes contact with the strike plate; used
to minimize friction.

rolling The use of heavy metal or stone rollers
on terrazzo topping to extract excess matrix.

rolling curtain A theater stage curtain that
rolls up on a horizontal drum or roll.

rolling cyclorama A cyclorama which can be
rolled around a vertical drum usually by means
of an electric motor.

rolling grille door A vertically moving rolling
door made up of a grille which is guided in a
track; has a horizontally mounted overhead
rolling mechanism.

rolling shutter door Same as roll-up door.

rolling shutters See roll-up door.

825

roll insulation

roll insulation A flexible blanket-type ther-
mal insulation in roll form; esp. used between
studs or joists in frame construction.

roll joint In sheet-metal work, a joint formed by
rolling the edges of adjoining sheets together
and then flattening the roll.

roll molding Any convex, rounded molding,
which has (wholly or in part) a cylindrical form.

rollock Same as rowlock.

roll roofing See asphalt prepared roofing.

roll-up door, rolling shutters A door made up
of small horizontal interlocking metal slats which
are guided in a track; the configuration coils about
an overhead drum which is housed at the head of
the opening; either manual or motor-driven.

rolock See rowlock.

rolock arch Same as rowlock arch.

rolok See rowlock.

Roman arch A semicircular arch. If built of
stone, all units are wedge-shaped; the usual arch
in Roman architecture.

•RDMAN-AKCH-ON-

Roman arch construction

Roman bath See balnea.

Roman brick Brick whose nominal dimen-
sions are 2 in. by 4 in. by 12 in. (5 cm by 10 cm
by 30 cm).

Roman bronze A copper-zinc alloy to which a
small quantity of tin has been added to give it
greater corrosion resistance and hardness.

Roman cement A quick-setting natural cement
that can harden under water and is relatively

impervious to water; made of a finely pulverized
calcined argillaceous limestone that has been
treated in a kiln at a temperature no higher than
that necessary to drive off carbon dioxide.

Roman Classicism See Classical Revival style.

Roman house A Classical Roman dwelling,
the external entrance of which opened into a
quadrangular court (atrium, l). In the ceiling of
the atrium, an opening (compluvium) to the sky
provided daylight and acted as an inlet for rain-
water, which was collected in a pool (impluvium)
sunk in the floor directly below the opening.

Romanesque Revival l.Same as Richard-
sonian Romanesque style. 2. A term sometimes
applied to the early works of James Renwick
(1818-1895) and Richard Upjohn (1802-1878)
using elements of the Romanesque style.

Romanesque style An architectural style
emerging in Western Europe primarily in the
1 1 th century and lasting until the advent of
Gothic architecture in the 12th century; based
on Roman and Byzantine elements; found espe-
cially in churches and castles; usually character-
ized by round arches and by massive articulated
walls, barrel vaults, groined vaults, ribbed vaults;
semicircular arches; served as the basis for the
Richardson Romanesque style and occasionally
used as a synonym for it.

Romanesque style

Roman mosaic A pavement that is tessel-
lated.

Roman order l.A seldom-used term for the
composite order. 2. Same as arch order, 1.

Roman Revival See Classic Revival.

Roman theater An open-air theater con-
structed by the ancient Romans; sometimes built
on a hillside, but more often on level ground —
usually with a richly decorated outer facade,

826

roof comb

with a colonnade gallery and vaulted entrances
for the public. The orchestra, 2 usually was a
half-circle; behind it was a stage having a richly
decorated proscenium and stage background.
Also see Greek theater.

Romantic style A loose term embracing a
variety of modes of architecture, often including
Exotic Revival, Gothic Revival, Greek Revival
style, Italianate style.

Roman tile A channel-shaped, tapered, single
lap, roofing tile.

rone Same as gutter, 1.

rondel See roundel.

rood A large crucifix, esp. one set above the
chancel entrance.

rood altar An altar standing against the nave
side of a rood screen.

rood arch The central arch in a rood screen;

rarely, the arch between nave and chancel over

the rood.
rood beam A horizontal beam extending

across the entrance to the chancel of a church to

support the rood.
rood loft A gallery or elevated platform estab-
lished upon the rood screen.
rood screen An ornamental altar screen that

separates the nave of a church from the chancel;

intended to carry a large crucifix (rood).
rood spire A spire over the crossing, 1 of the

nave and transepts.

rood stairs Stairs by which the rood loft is
approached.

rood stair turret A stair turret, 2; used when a
rood stair projects above the roof of the church.

rood tower A tower built over the crossing, 1
and hence approximately above the rood.

roof The top covering of a building, including all
materials and constructions necessary to support it
on the walls of the building or on uprights; provides
protection against rain, snow, sunlight, extremes of
temperature, and wind. For definitions and illustra-
tions of the different types, see barrel roof, bellcast
roof, bonnet roof, bowed roof, broken-pitch roof,
bunker fill roof, butterfly roof, candle-snuffer roof,
canopy roof, collar-beam roof, compass roof, coni-
cal roof, curb roof, deck roof, double-gable roof,
double-hipped roof, double-pitched roof, dropped
roof, dual-pitched roof, Dutch gambrel roof,

timbers in a roof: a, wall plate; b, tie beam; c, king post; d,
strut; e, principal rafter; /, pole plate; g, purlin; h, ridgeboard

Dutch hipped roof, Dutch roof, Dutch slice-hip
roof, earth roof, English gambrel roof, flat roof,
Flemish roof, flounder roof, French roof, gable-on-
hip roof, gable roof, gambrel roof, Gothic roof,
helm roof, hip-on-gable roof, hipped-gable roof,
hipped roof, hip-on-gable roof, hyperbolic parabo-
loid roof, Italian roof, jack roof, jerkinhead roof,
kick roof, knee roof, landscaped roof, lean-to roof,
mansard roof, monitor roof, M-roof, New England
gambrel roof, ogee roof, open roof, pavilion roof,
pent roof, pigeon roof, pitched roof, ponded roof,
principal roof, purlin roof, pyramidal roof, queen-
post roof, rainbow roof, ridge roof, round roof, sad-
dle-back roof, saltbox roof, segmental roof, shed
roof, ship's bottom roof, single-pitched roof, skirt-
roof, slice-hip roof, sod roof, span roof, square roof,
Swedish gambrel roof, terrace roof, thatched roof,
truncated roof, umbrella roof, visor roof, wagon
roof, whaleback roof.

roofage Same as roofing.

roof balustrade A railing with supporting
balusters on a roof, often near the eaves or sur-
rounding a widow's walk. (See illustration p. 828.)

roof batten Same as slate batten.

roof board One of a number of boards that
cover the upper surface of rafters so as to serve as
a base for the application of a roof covering, such
as shingles.

roof cladding See roofing, 1.

roof comb, roof crest A wall along the ridge
of a roof; used to give an appearance of addi-
tional height.

827

roof covering

roof balustrade

roof covering 1. All the materials laid on the
roof frame; includes sheathing, the outer
cladding materials, asphalt paper, etc. 2. A roof
covering, 1 which is not readily flammable and
does not slip from position. The following classes
have these and additional properties: Class A is
effective against severe fire exposure, does not
carry or communicate fire, and affords a fairly
high degree of fire protection to the roof-deck.
Class B is effective against moderate fire expo-
sure, does not readily carry or communicate fire,
and affords a moderate degree of fire protection
to the roof-deck. Class C is effective against light
fire exposure, does not readily carry or communi-
cate fire, and affords a slight degree of fire protec-
tion to the roof-deck.

roof crest See roof comb.

roof cresting See cresting.

roof-deck 1. The flat portion of a roof, used as a
terrace, for sunbathing, etc.; compare with deck
roof. 2. The structural material between the roof
supports used as a base for the roof covering sys-
tem; may be metal, concrete, wood, gypsum, or a
combination of these or similar materials.

roof decking Prefabricated units, usually in
the form of long structural panels, which span
the roof framing system and form a roof-deck, 2.

roof dormer See dormer.

roof drain A drain designed to receive water
collecting on the surface of a roof and to dis-
charge it into a leader or a downspout.

roof drainage system On the roof (or at the
roof line) of a building, a system composed of

roof decking

Safety Slots

Non-RU3lingDome

Seepage
Cpcivnq^

typical roof drain

DOWNSP0UTV
IRON, CLAY TILE.

■ ll

Oft CONCRETE PIPE l^M

GRADE |H
\ 1

FKOSUINE^^ i "^ 1

TO STOMA *(L- A
WATER DRAIN, tTj*"
MY Will, OR r~~7

surface outlet J !

u? : \ i y

lower portion of a roof drainage system

828

roof line

storm-water collection devices, and piping con-
nected to these collection devices; transports the
rainwater off the roof and out of the building.

roofed ingle A chimney corner.

roofer A term once used for a roof board.

roof flange A flange which fits around a pipe
that penetrates a roof; used on the upper side to
provide a raintight installation.

roof framing The assemblage of roof members
which provide support for the roof covering.

HIP JACK
RAFTER

COMMON
RAFTER

PLATE

roof framing

roof gallery
roof garden

on a roof.
roof guard
roof gutter
roof hatch

See widow's walk.

A garden or restaurant, or the like,

Same as snow guard.
See gutter, 1 .

A hinged panel unit, providing a
weathertight means of access to a roof.

roofing Any material (or any combination of
materials) used as a roof covering, such as corru-
gated metal, sheet metal, shingles, slate, thatch,
or tile; usually provides waterproofing, wind-
proofing, and thermal insulation.

roofing assembly The combination of all of
the elements used in constructing a roof: the
roof deck, substrate or thermal barrier, insula-
tion, vapor retarder, underlayment, interlay-
ment, base plies, and roof covering.

roofing board In a wood-framed house, a wide
board that is placed over the rafters, parallel to
the ridge beam.

roofing bond A guarantee by a surety com-
pany that a roofing manufacturer will repair a
roof membrane or covering under the conditions
listed in the bonding contract.

roofing bracket A bracket, used on a sloping
roof, which is fastened to the roof or is supported
by ropes fastened over the ridge and secured to a
suitable object.

roofing felt See asphalt prepared roofing.

roofing nail A short nail having a barbed or ring
shank and a comparatively large flat head; may be
galvanized or bright; often provided with a neo-
prene, lead, or plastic washer; used to secure roof-
ing felt or shingles to a roof-deck or roof boards.

LARGE HEAO, PLAIN SWANK
< 3

NEOPRENE *ASHER ATTACHED, PLAIN SHANK

NEOPRENE WASHER ATTACHED, SCREW SHARK

■ ■J 1 1 1 1 1 ! II f 1 If

BA8BE0 SHANK WITH LEAP WASHER

roofing nails

roofing paper See asphalt prepared roofing,
asphalt paper, building paper.

roofing putty A heavy asphaltic material used
to caulk metal roofs.

roofing sand A fine, white silica sand.

roofing slate See slate.

roofing square An area of 100 sq ft (9.3 m 2 ) of
roofing surface.

roofing system An assembly of components
which provide roofing.

roofing tile A tile for roofing, often fabricated
of clay or slate that has been treated in a kiln at
an elevated temperature; also available in many
types of materials and a variety of configura-
tions; see clay tile, mission tile, pantile, ridge tile,
Spanish tile.

roof insulation 1. A board-type product, usu-
ally of low or medium density, made of mineral
fibers, cellular glass, foamed plastic, lightweight
concrete, wood fiberboard, or other materials,
one or both sides of which may be faced with
another material; provides thermal insulation in
a roofing system. 2. Lightweight concrete which
is used primarily for thermal insulation over a
structural roof system.

roof ladder A cat ladder.

roof light Same as skylight.

roof-light sheet A sheet of transparent mate-
rial used to glaze an opening in a roof.

roof line The contour or shape of a roof.

829

roof live load

roof live load The load exerted on a roof other
than the roofing system and its supporting mem-
bers; the live load on the roof.

roof pitch The slope of a roof, usually expressed
as the angle of pitch in degrees or as a ratio of
vertical rise to the horizontal run.

LINE LENGTH OF
RAFTER

\-*— KIM— *i

roof pitch

roof plate A horizontal structural member that
receives and supports the lower ends of the
rafters of a roof; same as top plate, 1 or wall plate.

roof pond A pond of water on a roof structure
that cools a building by evaporation. Because
the water increases the thermal mass of the
building, it also increases the gain in solar
energy, storing the absorbed energy during the
day, when it is abundant, for later use.

roof principal A roof truss.

roof purlin Same as purlin.

roof saddle A saddle, 3.

roof scuttle A roof hatch.

roof sheathing The boards or sheet material,
especially plywood, fastened to the roof rafters,
onto which the shingle or other roof covering is
laid.

roof sign A board, poster, lighting display, or
the like, erected and maintained on or above the
roof of a building, usually to advertise or impart
information.

roof slating See slating.

roof slab A slab of reinforced concrete that

serves as a flat roof.
roof space Space (generally unused) between

the roof and the ceiling of the highest room.
roof structure A structure on a roof or above

any part of a building, such as a cooling tower or

sign support.

plywood roof sheathing

roof tank A water-storage tank on a roof.
roof terminal The termination of a vent pipe
at the roof.

FLASHING

roof terminal

roof tie
roof tile
rooftop

1. A collar beam. 2. A tie beam.
See roofing tile.

The roof of a house or other building.

rooftop unit A factory-made, encased room air
conditioner that is mounted atop a roof to pro-
vide cooling for the rooms below.

rooftree The ridgeboard of a roof.

roof truss A structural support for a roof.

roof truss

830

rose nail

roof valley See valley.

roof vent 1 . A ventilation device for an attic or
roof cavity. 2. Above a legitimate theater, one of
two or more vents above the stagehouse, con-
structed to open automatically in case of fire,
with an aggregate clear opening area of not less
than 5 percent of the area of the stage.

roof ventilator A ventilator, 1 on the roof of a
building, usually designed to exclude rain and
snow. Also see ridge ventilator.

roof ventilators

rookery 1. A tenement or dilapidated group of
dwellings. 2. A building with many diverse
occupants and rooms, such as a boardinghouse.

room In a building, a particular portion, an
enclosure or division separated from other divi-
sions by partitions.

room air conditioner, packaged air condi-
tioner, unit air conditioner, unit cooler
A factory-made encased unit which is designed
to deliver conditioned air to an enclosed space
without the use of ducts; usually mounted in a
window or in an opening in a wall, or as a console.

room acoustics Same as acoustics, 2.

room criterion curves See RC curves.

room-door lock An inside-door lock.

room monitor See monitor.

room velocity The velocity of air in the occu-
pied zone of an air-conditioned space, expressed
in feet per second (m/s).

root That portion of a tenon in the plane of the
shoulders.

root-balled Said of a growing plant that has
been prepared for transplantation; the largest
part of its root system (together with the soil
that surrounds it) is retained in the shape of a
ball. Also see balled and burlapped.

root cellar A structure, either partially or
wholly below ground level, that is used to store
root crops, such as potatoes and beets, at a cool
temperature; also see potato barn.

rooter A heavy-duty ripper intended to remove
roots of trees.

rope A strong thick line, comprised of a number
of twisted or braided strands of fiber (such as
hemp) or of wire (see wire rope).

rope caulk A preformed bead of tacky caulking
compound; often contains twine reinforcement
to facilitate handling.

rope drum The drum of a hoist, 2 on which the
hoisting cable or rope is wrapped.

roped hydraulic elevator A hydraulic ele-
vator in which the piston is connected by wire
ropes (cables) to the elevator car for hoisting it;
the driving mechanism includes a hydraulic
cylinder, piston, sheaves (and their guides),
tanks, hydraulic pump, and associated valves.

rope molding A bead or torus molding carved
in imitation of a rope; also see cabling.

rope suspension equalizer A device in-
stalled on an elevator car or counterweight to
equalize automatically the tensions in the hoist-
ing wire ropes.

ropiness Hills and valleys in a paint film cre-
ated by bristles in a brush when the paint is
applied; usually caused by the poor flow of the
paint or by brushing into a semidried film.

rosace See rosette, 1.

rose A metal plate attached to the face of a door,
around the shaft for the doorknob; sometimes
acts as a bearing surface for the knob.

rose bit A bit used to countersink holes in wood.

rose molding An ornament used esp. in Nor-
man architecture, chiefly during its later and
richer period.

rose molding

rose nail A nail with a conical head which is
hand-hammered into triangular facets.

831

rosette

rosette l.A round pattern with a carved or
painted conventionalized floral motif; a rosace.
2. A circular or oval decorative wood plaque
used in joinery, such as one applied to a wall to
receive the end of a stair rail. 3. An ornamental
nailhead or screwhead.

rosette, 1

rose window, Catherine-wheel window,
marigold window, wheel window A

large, circular medieval window, containing
tracery disposed in a radial manner.

rose window

rosewood See bubinga, Brazilian rosewood,
East Indian rosewood.

rosin, colophony A resin obtained as a
residue in the distillation of crude turpentine
from the sap of pine trees (gum rosin) or from an
extract of the stumps and other parts of them
(wood rosin).

rostral column A column, in honor of a naval
triumph, ornamented with the rostra or prows of
ships.

rostrum A platform, elevated area, pulpit, or
the like for addressing an audience.

rot Decomposition in wood by fungi and other
microorganisms; reduces its strength, density,
and hardness. Also see brown rot, white rot.

rotary cutting, rotary slicing A method of
cutting wood veneer in which a log is fixed in a
lathe and rotated against a knife so that the
veneer is peeled from the log in a continuous
sheet; used to produce softwood veneer and low-
grade hardwood veneer.

rotary drill A machine for opening holes in
rock or earth by means of a cutting bit at the end
of a metal shank; usually turned by a hydrauli-
cally or pneumatically driven motor.

rotary float, power float A motor-driven
revolving disk that smooths, flattens, and com-
pacts the surface of concrete floors or floor
toppings.

rotary float

rotary oil burner In an oil furnace, a burner

in which atomization takes place by feeding oil

to a rapidly rotating cup.
rotary spreader A mechanical device which

spreads fertilizer and/or seed outwardly as it

rotates.
rotary trowel Same as rotary float.
rotary veneer Wood veneer obtained by

rotary cutting.
roto operator A gear-driven device, turned

with a small crank handle or knob; used to open

and close jalousies, awning windows, casement

windows, and fanlights.

roto operator

*>,2

rough rendering

rotten knot See unsound knot.

rottenstone A soft, friable limestone; in pul-
verized form, used for polishing soft metal sur-
faces and wood.

rotunda l.A circular building, especially one
with a dome. 2. A circular hall in a large build-
ing, esp. one covered by a cupola.

rough arch Same as discharging arch; built
with rectangular bricks and wedge-shaped mor-
tar joints.

rough ashlar A block of stone, as brought from
the quarry.

rough-axed brick An axed brick.

roughback l.A side cut of stone (a slab) hav-
ing one side sawn and the other rough; cut from
a block fed through a gang saw. 2. In masonry, a
concealed end of a stone laid as a bondstone.

rough bracket A bracket under stair steps, fas-
tened to the supporting carriage.

rough brick arch A brick arch made up of
rectangular bricks that are neither cut nor
tapered to voussoir shape; the required curvature
is achieved by additional mortar in the joints.

rough buck See subframe, 1.

rough carpentry In a building of wood-frame
construction, that part of the framing, 2, which
includes boxing and sheeting.

rough carriage A carriage, 1 which is un-
planed, usually concealed from view.

roughcast Same as rock dash.

roughcast glass See rough plate glass.

rough coat A scratch coat of plaster.

rough-cut joint, flat joint, flush joint,
hick joint The simplest joint in masonry;
made by holding the edge of the trowel flat
against the brick and cutting in any direction,

rough-cut joint

so that the mortar in the joints is made smooth
with the wall surface. Because this cutting
action produces a small hairline crack, the joint
is not always watertight.

roughened finish tile Tile whose plane sur-
faces are entirely broken by mechanical means,
such as wire cutting or wire brushing, to provide
for a more effective bond for mortar, plaster, or
stucco.

rough floor A layer of boards or plywood,
nailed to the floor joists, which serves as a base
or subfloor for the finish floor.

rough flooring Material used for the rough
floor, either sheets of plywood or rough boards
(often unplaned).

rough grading Cutting and filling of earth pre-
liminary to the final work.

rough grind The initial smoothing operation
in which coarse abrasives are used to cut the pro-
jecting chips in hardened terrazzo down to a
level surface.

rough ground l.A piece of linear blocking
used to fix the approximate position of a desired
planar surface. 2. See ground, 1.

rough hardware In building construction,
hardware meant to be concealed, such as bolts,
nails, screws, spikes, and other metal fittings.

roughing-in l.The first coat of plaster in
three-coat plasterwork. 2. The rough work in
any phase of construction. 3. Installing the con-
cealed portion of a plumbing system to the point
of connection for the fixtures.

roughing-out In carpentry, a preliminary
shaping operation.

rough lumber Sawn lumber that has not been
planed; also called undressed lumber.

rough opening An opening in a wall, or the
framework of a building, into which a door-
frame or window frame, subframe, or rough
buck is fitted.

rough plate glass, roughcast glass Translu-
cent, rolled sheet glass, one face of which has a
slightly rimpled texture.

rough pointing In masonry, the troweling of
mortar in brickwork in a rough-and-ready manner.

rough rendering The application of a coat of
a plaster without smoothing the surface, which
is left rough.

833

rough rolled glass

rough rolled glass Same as patterned glass.
rough rubble A well-bonded rubble wall.

rough sawn The wood surface that results
from a gang-sawing process.

rough service lamp An incandescent lamp
designed to resist failure due to impact; uses
extra filament supports which result in lowered
efficiency.

rough sill 1. In frame construction, the sill, 1 on
which the building frame is erected. 2. The wood
piece laid across the bottom of a rough opening
to act as a base for a window construction.

rough string, rough stringer 1. A notched,
generally unplaned, inclined board which sup-
ports the steps of a wooden stairway, usually con-
cealed from view. 2. A carriage, 1.

rough work The rough framework of a build-
ing, including framing, boxing, and sheeting.

round l.A wood plane for cutting grooves. 2.
See round molding. 3. A cylindrical metal rod.

round arch A semicircular arch.

Round Arch style An architectural style used
infrequently in the mid- 19th century; character-
ized by arcaded round arches, primarily in
masonry buildings; also see Rundbogenstil.

Round Arch style

round barn A barn having a circular plan; see

circular barn,
round billet molding Same as roll billet

molding.

round church One whose plan is a circle; by
extension, a church designed around a central
vertical axis such as those of polygonal or Greek-
cross form, though these are more accurately
described as churches of the central type.

round church, plan

round dormer A dormer having a circular
window in its face.

rounded forend See rounded front.

rounded front, (Brit. ) rounded forend A lock
front which is shaped to conform to the rounded
edge of a double-acting door (swinging door).

rounded step See round step.

rounded tile 1. Same as Mission tile. 2. One of
the tiles in a course of tiles whose lower edges are
semicircular; has the appearance of a series of
scallops; see imbrication.

roundel l.A small circular panel or window;
an oculus. 2. In glazing, a bull's-eye or circular
light like the bottom of a bottle. 3. A small bead
molding or astragal. 4. In stage lighting, a glass
or gelatin color filter used in a borderlight.

round-headed Same as round-topped.

roundhouse A house that is round in plan,
with no exterior corners.

round knot A knot sawn across so that it is
approximately circular.

round molding, round A fairly large mold-
ing, the section of which is circular (or nearly
circular) and convex.

round notch A synonym for saddle notch.

round pediment A rounded pediment, 2 used
ornamentally over a door or window.

round pediment

834

rowlock

round ridge The ridge of a roof, finished with a

rounded surface.
round roof Same as rainbow roof.

round step, rounded step, round-end step

A step having a bullnose.

round timber Felled trees which have not
been converted to lumber.

round-topped A term descriptive of a window,
door, or arch having a semicircle at its head.

work, cutting out the narrow channels in which

metal or colored woods are laid.
router patch A piece of plywood or veneer

having parallel sides and rounded ends; used to

repair a defect in a surface.
router plane, plough, plow A plane used for

cutting and smoothing grooves which have their

bottoms parallel to the surface; has a handle at

each end and a centrally located cutting tool.

BLADE

GLADE-ADJUSTMENT

'THUMBSCREW

round-topped window with curved muntins at top

round-topped roll In sheet-metal roofing, a
joint which is formed over a roll, 1,2.

round tower In early Christian architecture,
esp. in Ireland, a conically capped circular tower
of stone construction; used for defense.

round window See Catherine-wheel window,
rose window, wheel window.

rout To groove, furrow, hollow out, or otherwise
machine a wood member with a router.

router l.A router plane. 2. A machine tool
having a rapidly revolving vertical spindle and
cutter; used for routing, cutting mortises, etc. 3.
A chisel having a curved point; used for cleaning
out grooves, mortises, etc.

router gauge A tool similar to a marking
gauge, but having a narrow chisel as a cutter
instead of a marking point; esp. used in inlaid

router plane

rover Any member, as a molding, that follows

the line of a curve.
row house, row dwelling l.One of an

unbroken line of houses sharing one or more

sidewalls with its neighbors. A group house. 2.

One of a number of similarly constructed houses

in a row; usually in a housing development.
rowlock, rolok, rollock 1 . A brick laid on its

edge so that its end is visible. 2. One ring of a

rowlock arch.

rowlock

835

rowlock arch

rowlock arch An arch wherein the bricks or
small voussoirs are arranged in separate concen-
tric rings.

rowlock arch

rowlock bond Same as rat-trap bond.

rowlock cavity wall, all-rowlock wall,
rolock wall, rolok wall, rowlock-back
wall, rowlock wall A brick cavity wall

built with all bricks laid on edge.

rowlock cavity wall

row spacing In timber construction, the dis-
tance between rows of bolts or similar fastenings
measured from center to center of the rows.

royal 1. A cedar shingle, about 24 in. (61 cm)
long and Vi in. (1.25 cm) thick at the butt.
2. In military architecture, an especially
strongly-defended medieval fort.

Royal Institute of British Architects
(RIBA) Founded in 1835, the RIBA has
been the authoritative organization for the pro-
fession of architecture in Britain; it qualifies
candidates for admission to the Institute, recog-
nizes a number of schools of architecture, and
awards prizes for outstanding work. Address: 66
Portland Place, London, WIN 4AD.

rpm Abbr. for "revolutions per minute."

RSC Abbr. for rolled steel channel, 1.

RSJ Abbr. for "rolled steel joist."

RT Abbr. for "raintight."

rubbed brick A brick having a rubbed finish, 2.

rubbed finish l.A stone finish between
smooth machine finish and honed finish,

obtained by mechanical rubbing. 2. A finish
obtained by using an abrasive to remove sur-
face irregularities from concrete or brick. 3.
On a varnished or shellacked wood surface, a
dull finish, usually produced by rubbing with a
pad which is saturated with pumice and water
or oil.

rubbed joint An edge joint formed by coating
the contacting surfaces with glue and rubbing
them together until glue no longer is expelled;
subsequent clamping need not be applied.

rubbed work Work in brick, concrete, wood,
or stone having a rubbed finish.

rubber 1 . A highly resilient material, capable of
recovering from large deformations quickly;
manufactured from the juice of rubber trees as
well as of other trees and plants. 2. Any of vari-
ous synthetically produced materials having sim-
ilar properties; an elastomer. 3. A cutter.

rubber-emulsion paint See latex paint.

rubber set See false set.

rubber silencer, bumper A resilient part,
such as a rubber button, attached to the stop on
a doorframe to reduce noise caused by slamming
of the door.

rubber tape A tape of rubber or a rubber-like
compound; used to provide electrical insulation
at joints.

rubber tile A hard-wearing flooring material;
composed principally of natural or synthetic
rubber with a filler of clay and fibrous talc or
asbestos; usually set in mastic over a wood or
concrete subfloor.

rubber-tired roller A heavy self-propelled or
towed vehicle which rolls on a parallel series of
pneumatic tires set on one or two axles; used to
compact soil.

rubbing See flatting down.

rubbing block In marble polishing, a block of
sandstone with which the preliminary operation
of smoothing is done by hand.

rubbing brick Same as rub brick.

836

run

rubbing down An intermediate step in finish-
ing a painted surface; rubbing with a mild abra-
sive before applying the topcoat.

rubbing stone A stone for polishing or erasing
the toolmarks on a stone, or on bricks for gauged
work after they have been rough-shaped.

rubbing varnish See polishing varnish.

rubbish A mixture of combustible waste such as
paper, cardboard cartons, wood scrap, and com-
bustible floor sweepings; contains up to 20% by
weight of restaurant or cafeteria waste but con-
tains little or no treated papers, plastic, or rubber
wastes. Also see garbage, refuse, and trash.

rubble Rough stones of irregular shapes and
sizes; used in rough, uncoursed work in the con-
struction of walls, foundations, and paving.

rubble arch See rustic arch.

rubble ashlar wall A rubble wall which has
an ashlar facing.

rubble concrete 1. Concrete similar to cyclo-
pean concrete except that small stones (such as
one man can handle) are used. 2. Concrete
made with rubble from demolished structures.

rubble drain See French drain.

rubble masonry Same as rubblework.

rubble stone masonry Stone masonry com-
posed of irregularly shaped units bonded by mortar.

rubble wall A wall, either coursed or un-
coursed, of rubble.

rubblework Stone masonry built of rubble.

rubblework

rub brick A silicon carbide brick used to
smooth and remove irregularities from hardened
concrete surfaces.

rudenture Same as cabling, 2.

ruderation The process of paving with pebbles
or small stones and mortar.

rudus The lower layer of mortar in the bedding
of a mosaic pavement.

rule An instrument having straight edges, usu-
ally marked off in inches or centimeters and
fractions thereof; used for measuring distance
and for drawing straight lines.

^5^^*^-^

STEEL ORFiaER&LA&S
RULE

STEEL RULE STEELOft FIBEftGLASS
' WITH HOLDER TAPE

common types of rules

ruled joint Same as scribed joint, 2.

rule joint A pivoted joint in which two flat

strips can be turned edgewise toward or from
each other, but in no other direction.

ruling pen A pen used to draw lines of even
thickness; commonly consists of two blades
which hold ink between them, the distance
between the points being adjusted by a screw.

Rumford fireplace An efficient fireplace
invented by Benjamin Thompson (1753-1814),
originally of Massachusetts, who later achieved
distinction as Count Rumford. His innovative
fireplace design increased the efficiency of radi-
ated heat and lessened the emitted smoke, bene-
fits that were achieved by significantly reducing
the size of the massive colonial fireplace opening
and by introducing a constriction in the chim-
ney directly above the hearth so as to increase
the draft through the chimney.

rummel Same as soakaway.

run 1 . In roofing, the horizontal distance from
the face of a wall to the ridge of the roof. 2. In
stairways, the width of a single stair tread.
3. The horizontal distance covered by a flight of
steps. 4. The runway or track for a sash. 5. A
small stream of paint flowing vertically on a

837

Rundbogenstil

to run a molding; travels sideways along the ceil-
ing line to build up a desired shape as plaster is
applied.

running off Applying the final coat of plaster
to a molding.

running ornament, running mold Any
molding ornament in which the design is con-
tinuous, in intertwined or flowing lines as in
foliage, meanders, etc.

run, 3

painted object; usually occurs with enamels if an
excessively thick coat is applied; also called tear.
6. That section of pipe or fitting continuing in a
straight line in the direction of flow in the pipe
to which it is connected.

Rundbogenstil A German architectural style
of the mid- 19th century; especially character-
ized by round arches, often with Romanesque or
Italianate features; the prototype of the Round
Arch style.

rung A bar, usually round in cross section, form-
ing the step of a ladder.

runic cross See Celtic cross.

Runic knot An interlaced or twisted orna-
ment common in Anglo-Saxon architecture.

run line A thin line of paint, applied by a lining
tool run along a straightedge.

run molding A molding of plaster, and occa-
sionally of cement or other such material,
formed by passing a metal or wood template over
the material while wet.

runner 1 . A metal supporting member which is
attached to structural steel members or concrete;
used to support partitions, acoustical ceiling tile,
etc. Also see main runner. 2. Same as ledger, 1.

running 1. Linked in a smooth progression,
inclining to the right or the left, within a band;
applied to various ornamental motifs. 2. Form-
ing a cornice in place with a running mold.

running bond Same as stretcher bond.

running dog See Vitruvian scroll.

running ground Earth in a plastic or semi-
plastic state, sand, etc., which will not stand
without sheeting.

running mold, horse mold A template
shaped to the configuration of a cornice and
mounted on a wooden frame; used by plasterers

running ornament

running screed A narrow strip of plaster used

in place of a running rule to guide the running of

a cornice or molding.
running shoe A piece of metal on a running

mold to prevent wear and allow it to slide freely

on the running rule and nib guide.
running slope The slope of a surface which is

parallel to the direction of travel; compare with

cross slope.
running tie A timber framing member that

interconnects joists, rafters, and/or studs.
running trap A depressed U-shaped section of

pipe in a drain; allows the free passage of fluid, but

always remains full, whatever the state of the pipe,

so that it forms a seal against the passage of gases.

running trap

run-of-bank gravel See bank-run gravel.

runoff The flow of rainwater away from the area

on which it has fallen.
run of rafter Same as run, 1.

run-to-breakdown maintenance The re-
placement of machinery parts only after a
machinery breakdown has occurred. Contrast
with on-condition maintenance.

runout A branch pipe from a hot-water main to
a convector.

runway 1. In the theater, a narrow projection of
the stage, over the orchestra pit and sometimes

838

rustic quoin

into the aisles of an auditorium, permitting the
actors to perform in close proximity to the audi-
ence. 2. A path taken by buggies of concrete on
decking over an area of concrete placement.

runway barn See Yankee barn.

rupture disk A safety device, used in a system
under pressure, consisting of a frangible disk
which ruptures when a predetermined pressure is
exceeded.

rupture member Any safety device which will
rupture automatically at a predetermined pressure.

rupture modulus See modulus of rupture.
rupture strength See modulus of rupture.
Ruskinian Gothic See High Victorian Gothic.

Russo-Byzantine architecture The first
phase of Russian architecture (11th to 16th cen-
tury) derived from the Byzantine architecture of
Greece; mainly stone churches characterized by
cruciform plans and multiple bulbous domes.

rust A substance, usually in powder form, of
light brownish red color, accumulating on the
face of steel or iron as a result of oxidation; ulti-
mately weakens or destroys the steel or iron on
which it is allowed to form.

rustic 1. Descriptive of rough, hand-dressed
building stone, intentionally laid with high
relief; used in modest structures of rural charac-
ter. 2. A grade of building limestone, character-
ized by coarse texture.

rustic arch, rubble arch An arch laid up with
rough or irregular stones, the spaces between
them being filled with mortar.

rustic brick A fired clay brick, often multicol-
ored, having a rough-textured surface; used for
facing work.

rusticated Said of cut stone having strongly
emphasized recessed joints and smooth or roughly
textured block faces; used to create an appearance
of impregnability in banks, palaces, courthouses,
etc. The border of each block may be rebated,
chamfered, or beveled on all four sides, at top and
bottom only, or on two adjacent sides; the face of
the brick may be flat, pitched, or diamond-point,
and if smooth may be hand- or machine-tooled.

rusticated column See banded column.

rusticating Applying a coarse texture on the
face of clay bricks or stone.

rustication Same as rustic work.

rustication

rustication strip A strip of wood, or the like,
which is fixed to the surface of a concrete form
to produce a groove or rustication in the
concrete.

rustic finish, washed finish A type of
terrazzo topping in which the matrix is recessed
by washing prior to setting, so as to expose the
chips without destroying the bond between
chip and matrix; a retarder sometimes is applied
to the surface to facilitate this operation.

rustic joint In stone masonry, a deeply sunk
mortar joint that has been emphasized by
having the edges of the adjacent stones cham-
fered or recessed below the surface of the stone
facing.

Rustic order Same as Tuscan order.

rustic quoin A quoin treated with sunken
joints, the face of the quoins being generally
roughened and raised above the general surface
of the masonry.

839

rustic siding

rustic siding See drop siding.

rustic slate One of a number of slate shingles of
varying thickness, yielding an irregular surface
when installed.

rustic stone Any rough, broken stone suitable
for rustic masonry, most commonly limestone or
sandstone; usually set with the elongate dimen-
sion exposed horizontally.

Rustic style A vague term denoting an architec-
tural mode rather than an architectural style, often
applied to hunting lodges or log cabins in forested
areas of the northeastern United States. Charac-
teristics include: wall construction of logs (often
peeled), saddle -notch corner joints, and rough-
cut lumber; a fieldstone chimney; a moderately
to steeply pitched roof covered by hand-split
wood shingles, a roof overhang with exposed
rafters; one or more balconies or porches with flat
balusters having decorative cutouts or stickwork.
Occasionally called Adirondack Rustic style or
Teddy Roosevelt Rustic style.

rustic woodwork Decorative or structural
work constructed of unpeeled logs or poles.

rustic 'work 1. Decorative or structural work
constructed of logs from which the bark has
not been peeled. 2. Roughly faced stonework;
the separate blocks are marked by deep cham-
fers.

rust-inhibiting paint An anticorrosive paint.

rust joint A watertight connection between
two sections of iron pipe made by filling the hub

rustic work

with any compound, such as iron cement, that

induces rusting; the compound also may be used

to cure a leaky joint.
rust pocket A cleanout at the base of a pipe

which permits removal of accumulated rust

debris.
rutile A common mineral, red-to-brown or black

in color; contains 60% titanium; used in paints, as

a coating on welding rods to stabilize the arc, and

as an opacifier in ceramic glaze and in glass.
R»value A measure of the thermal resistance of

a material or component.
R/W l.On drawings, abbr. for right-of-way. 2.

Abbr. for "random widths."
R/W&L Abbr. for "random widths and lengths."

840

S Symbol for "second."

S l.On drawings, abbr. for "side." 2. On draw-
ings, abbr. for "south." 3. Abbr. for "seamless."

S&E In the lumber industry, abbr. for "surfaced
one side and edge."

S&G Abbr. for "studs and girts."

S&M Abbr. for "surfaced and matched."

S1E In the lumber industry, abbr. for "surfaced
one edge."

SIS Abbr. for "surfaced one side."

S 1 S IE Abbr. for "surfaced one side and one edge."

S1S2E Abbr. for "surfaced one side and two
edges."

S2E Abbr. for "surfaced two edges."

S2S Abbr. for "surfaced two sides."

S2S&CM Abbr. for "surfaced two sides and
center matched."

S2S&SL Abbr. for "surfaced two sides and
shiplapped."

S2S1E Abbr. for "surfaced two sides and one
edge."

S4S Abbr. for "surfaced four sides."

S4S&CS Abbr. for "surfaced four sides and
caulking seam."

S/A Abbr. for "shipped assembled."

Sabbath house, Sabbath-day house In
colonial New England, a small house having but
a single room with a fireplace at one end, usually
located near a house of worship; used on Sun-
days by a family as a place in which to warm and
feed themselves during breaks in the all-day reli-
gious services, because such services typically
were conducted in unheated meeting houses.
Occasionally several families shared a two-room
house with a centrally located fireplace; others
had a small two-story house for this purpose,
with the ground floor used as a stable. Also see
Sunday house.

saber saw A power-driven saw with an oscillat-
ing blade which extends through the base of the
saw; has an action similar to that of a jigsaw.

sabin A unit of sound absorption equivalent to
1 sq ft of perfectly absorptive surface. Also see
metric sabin.

sable, sable pencil A fine paintbrush made of
hair of the tail of the sable.

sable writer A long sable, esp. one used in let-
tering signs.

sacellum A small Roman sanctuary, usually an
unroofed enclosure with a small altar. Some-
times, a roofed funerary chapel.

sack See bag.

sack finish See sack rub.

sack rub, sack finish A finish for f orated
concrete surfaces; designed to produce even tex-
ture and fill all pits and air holes; after the sur-
face is dampened, mortar is rubbed over it; then,
before it dries, a mixture of dry cement and sand
is rubbed over it with a wad of burlap or a
sponge-rubber float to remove surplus mortar
and fill voids.

sacrarium Any consecrated place, in Roman
or medieval architecture; a shrine, a chapel, or a
sacristy for keeping liturgical objects.

sacrarium: Pompeii

sacrificial anode A metal plate used in

cathodic protection (i.e., the protection from
corrosion) of piping or other equipment to
which it is electrically connected. This metal

841

sacrificial protection

plate must be more corrodible than the piping to
which it is attached.

sacrificial protection The use of a metallic
coating, such as a zinc-rich paint, to protect
steel. In the presence of an electrolyte, such as
salt water, a galvanic cell is set up and the metal-
lic coating corrodes instead of the steel.

sacrificial timber A timber which is purposely
oversized to enhance its fire resistance.

sacristy A room in a church, near the chancel,
where the robes and altar vessels are stored,
where the clergy vest themselves for services,
and where some business of the church may be
done; usually a single room, but sometimes a
very large one.

sacristy

saddle l.Same as threshold. 2. A cricket. 3.

Any hollow-backed structure suggesting a sad-

saddle, 1

Saddle

Floor stab

saddle, 4

die, as a ridge connected to two higher eleva-
tions or a saddle roof. 4. A floor mount for a
heavy pipe.

saddleback 1. A saddle joint. 2. A coping stone
having its top surface sloped with its high point
along the center ridge, so that rainwater spills on
either side; also called saddle-backed coping.

saddle, 2

saddleback, 2

saddleback board Same as threshold.

saddleback coping brick Same as saddle-
back, 2.

saddle-backed coping See saddleback, 2.

saddleback joint Same as saddle joint, 1 .

saddleback roof Same as saddle roof.

saddlebag cabin Two one-room log cabins
that are connected and share a shingled roof
having a single pitch on each side of a central
ridge. The two cabins have separate entrances
and usually there is no interior door between
them; there is often a full-width porch across the
entire facade. In the Northern United States, a
central chimney is common, so the cabins are
usually joined back-to-back, sharing the same
chimney stack; in contrast, in the South, there is
a chimney at the end of each cabin. Compare
with center-hall cabin.

842

safety belt

saddle bar One of the horizontal iron bars
across a window opening which secure the
leaded lights.

saddle bead A type of glazing bead used to
secure two panes of glass.

saddle bend A saddle-shaped bend in a con-
duit, where it crosses another conduit, in order
to clear it.

saddle board A board at the ridge of a pitched
roof which covers the joint at the ridge. Also see
comb board, ridgeboard.

saddle coping A saddle-backed coping; see
saddleback, 2.

saddle fitting A fitting for making a connec-
tion to a pipe which is already installed;
clamped to the outside of the pipe and sealed
with a gasket.

saddle flange A curved flange, usually welded
or riveted to a tank, boiler, or the like; shaped to
fit the curved surface and receive a threaded
pipe.

saddle flashing Flashing over a cricket.

saddle-jib crane Same as hammerhead crane.

saddle joint 1. A stepped joint in a project-
ing masonry course or in a coping; used to pre-
vent the penetration of water. 2. A vertical
joint in sheet-metal roofing; formed by bend-
ing up the end of one sheet and folding it
downward over the turned-up edge of the
adjacent sheet.

saddle joint

saddle notch At a corner in log cabin con-
struction, a rounded notch cut near one end in

saddle notches

the lower surface of a horizontal log; forms an
interlocking joint when mated with a similarly
notched log set at a right angle to it. Occasion-
ally, this term is also used for a double-saddle
notch, which is cut in both sides of a round log;
in such instances, the logs at right angles are
unnotched.

saddle piece In sheet-metal roofing, a metal
cricket.

saddle roof A roof having a concave-shaped
ridge with gables at each end of the roof, this
configuration being suggestive of a saddle.

saddle scaffold A scaffold erected over the
ridge of a roof; esp. used for repairing chimneys.

saddle stone l.An apex stone. 2. Obsolete
term for a stone containing saddle-shaped
depressions.

saddle tenon See bridlejoint, 2.

saddle tie l.For wire hangers, the attachment
of wire hangers to main runners. 2. For furring,
the attachment of furring members to framing
members of wall or ceiling assemblies by the use
of a single or double strand of wire.

sadl Abbr. for saddle.

SAE Abbr. for "Society of Automotive Engineers."

SAF On drawings, abbr. for "safety."

safe 1. A tray with a waste pipe; placed below a
fixture to catch overflow, below a pipe to catch
leakage, etc. 2. A built-in or portable steel-
enclosed repository, designed to protect stored
materials against fire and/or burglary.

safe area An exterior or interior space that
serves as a means of egress from a building by
providing a transitional area from, or a normal
means of entry to, an assembly space.

safe leg load That load which can be imposed
safely on the frame leg of a scaffold.

safe life A life of a structural supporting ele-
ment which is many times that actually
required to avoid the element's mechanical
fatigue.

safe load A load on a structure which does not
produce stresses in excess of allowable stresses.

safety See elevator car safety.

safety arch A discharging arch.

safety belt A device, usually worn around the
waist, which is attached to a structure or lifeline
to prevent a worker from falling.

843

safety cage

safety cage A lightweight rig, usually used with
a power-operated winch, sometimes used in
place of a scaffold for relatively minor jobs.

safety chain A chain attached to a piece of
equipment to prevent its falling should the
equipment fastener fail.

safety counterweight A mechanical device
attached to an elevator-car frame to stop and
hold the car (or its counterweight) in case of a
predetermined overspeed, free fall, or a slacken-
ing of the hoisting cables.

safety curtain See asbestos curtain.

safety factor Same as factor of safety.

safety fuse A flexible cord containing an inter-
nal burning medium by which fire is conveyed at
a continuous and uniform rate for the purpose of
firing blasting caps.

safety glass 1. Wire glass. 2. Tempered glass. 3.
Laminated glass.

safety lighting See emergency lighting.

safety lintel An auxiliary lintel, usually of
wood, placed behind a stone lintel in the aper-
ture of a door or window.

safety nosing For a stair, nosing having an
abrasive nonslip surface flush with the tread
surface.

safety shutoff device In a gas burner, a
device that will stop the gas supply if the gas
flame is extinguished.

safety switch A switch used in interior electric
wiring which is mounted inside a metal box and
operated from outside the housing by means of a
handle connected to the switch mechanism.

safety switch

safety tread A tread on a stair, esp. to prevent
the foot from slipping; usually has a roughened
surface or strips which are roughened.

safety valve See pressure-relief valve.

safe waste The waste pipe from a safe, 1.

safe working pressure The maximum work-
ing pressure for a given vessel, boiler, flask, or
cylinder, allowable under the American Society
of Mechanical Engineers Boiler Code; usually
stamped on the unit.

safflower oil A drying oil obtained from saf-
flower seeds; used in paints; has properties simi-
lar to linseed oil.

safing 1 . A barrier which is placed in an air duct
around a component (such as a filter) to ensure
that air flows through the component rather
than around it. 2. In multi-story construction, a
fire-stop in the space between the floor slab and
a curtain wall, 1 to help retain the integrity of
fire-resistance ratings. 3. The fire safety insula-
tion around floor perimeters between the floor
slabs and the spandrel panels, which seals off any
such openings in floors and walls. Also called
safing off.

sagging 1 . A defect characterized by a wavy line
or lines appearing on those surfaces of porcelain
enamel that have been fired in a vertical posi-
tion. 2. A defect characterized by irreversible
downward bending in a ceramic article insuffi-
ciently supported during the firing cycle. 3. The
excessive flow of a wet paint film on vertical sur-
faces resulting in drips, runs, or curtains in the
film when it dries. 4. The flowing of a sealant
within a joint, so that it loses its original shape.
5. See curtaining, 3.

sagitta The keystone of an arch.
sahn Central court of a mosque.
sailing course An oversaving course.

sailor A brick that is laid on end (i.e., posi-
tioned vertically), with its wider face showing
on the wall surface; compare with soldier.

sail-over Any projection or jutting beyond the
general wall surface.

Saint Andrew's cross bond See English
cross bond.

Saint Augustine house In Saint Augustine,
Florida, after it was settled by the Spanish in
1565, a two-story house with very thick walls

844

saltbox roof

constructed of blocks of tabby or coquina, usu-
ally roofed with hand-split cypress shingles; one
room on the ground floor facing the street, with
windows protected by gratings (rejas) and solid-
wood interior shutters; two rooms on the upper
floor, accessible by way of an exterior stairway;
usually one or two balconies. Also see palma
house and tabla.

sala In Spanish architecture and its derivatives,
a reception room, main hall, or living room in a
house; usually has windows facing the street that
are protected by grilles or wood gratings (rejas),
and also by heavy interior shutters.

salamander A portable stove used in cold
weather to heat the air around freshly placed
concrete in order to sustain proper curing con-
ditions.

sal ammoniac, ammonium chloride A
material used in a soldering flux and as an ingre-
dient in iron cement.

sale-and-leaseback A contractual agreement
between an owner and an investor, under which
the owner sells a property to the investor and
then improves or develops it under the condi-
tion that the investor gives him a long-term
lease of the premises.

sal e pepe A granite having a crystalline struc-
ture composed of fine-grained minerals resem-
bling a mixture of salt and pepper.

sales square In the US, the quantity of pre-
pared roofing required to cover 100 square feet
(9.3 m 2 ) of deck.

saliens An artificial fountain in which water
shoots up through a constricted tube, under its
own pressure.

salient Describing any projecting part or mem-
ber, as a salient corner.

salient corner A corner which projects out-
ward; the opposite of a reentrant corner.

sally A projection, as the end of a rafter beyond
the notch which has been cut to fit over a hori-
zontal beam.

sally port A gate, secret door, or underground
passageway in a medieval castle provided for
troops going forth on a sortie.

salmon brick A poor quality brick that lacks
weather resistance; so named because of its pink
color; commonly used to fill spaces between
interior structural timbers in a timber-framed

house in order to provide increased structural
rigidity and improved thermal insulation.

salomonica A twisted or spiral column.

salon 1. A room used primarily for exhibition of
art objects. 2. A drawing room. 3. A small, styl-
ish place of business.

saloon l.A place where intoxicating liquors
are sold and consumed; often the social center in
many early towns of the Western United States.
2. A variant form of salon.

saltbox house In colonial New England, a
timber- framed house, commonly two and one-
half stories high, having a hall-and-parlor plan;
gables at each end wall; a sloping roof with slope
on the rear side of the ridge much longer and less
steep than the slope on the front side. This roof
contour gave the house a shape resembling a box
for holding salt used at that time in the British
colonies.

saltbox house

saltbox roof Any roof having a configuration
similar to that of a saltbox house. In the South,
often called a catslide.

saltbox roof

845

salt-glazed brick

salt-glazed brick, brown-glazed brick Brick

having a glossy finish, obtained by thermochemi-
cal reaction between silicates of clay and vapors of
salt or other chemicals, produced in a kiln.

salt-glazed tile Facing tile whose surface faces
have a lustrous glazed finish, obtained from the
reaction of the silicates of the clay body with
vapors of salt or other chemicals produced in a
kiln.

salutatorium In medieval churches, a porch or
a portion of the sacristy where the clergy and the
people could meet and confer.

salvage In a building under repair or recon-
struction, the saving of damaged or discarded
material, for use or resale, which otherwise
would be a total loss.

salvaged brick Brick that has been used
previously.

samel brick Same as salmon brick.

sammel A salmon-colored underfired brick of
poor quality.

sample A small specimen of material, or a single
unit of many such items to be furnished, which is
in conformity with the requirements for the speci-
fications; furnished for review and approval; estab-
lishes standards by which work will be judged.

sample panel A small area of plasterwork,
brickwork, or the like that is intended to serve as
a standard of comparison for work yet to be done.

SAN On drawings, abbr. for "sanitary."
sanctuary l.In a church, the immediate area
around the principal altar; the chancel. 2. The
sacred shrine of a divinity.
sanctum sanctorum l.The innermost or
holiest place of a tabernacle or temple, the "holy
of holies." 2. Any especially private place or
retreat which may not be entered except by spe-
cial permission.

sanctus bell A bell hung in an exterior turret
or a bell cot over or near the chancel arch,
which was rung to fix the attention of those not
in the church to the service of the mass.

sand 1. Granular material which passes through
a 9.51-|im (%-in.) sieve, almost entirely passes
through a 4-76-mm (No. 4) sieve, and is
predominantly retained on a 74-|lm (No. 200)
sieve; results from natural disintegration and
abrasion of rock or processing of completely

sanctus bell

friable sandstone. 2. That portion of an aggre-
gate passing through a 4-76-mm (No. 4) sieve
and predominantly retained on a 74-|lm (No.
200) sieve. Also see sieve number.

sandal brick Same as salmon brick.

sand asphalt l.A hot-laid mixture of local
sand and asphalt cement, prepared without spe-
cial control of aggregate grading. 2. A mixture of
local sand, with or without a mineral filler, and a
liquid asphaltic material.

sandbag In the backstage of a theater, a canvas
bag filled with sand which is used to counterbal-
ance hanging scenery or other equipment.

sandblast To use sand, propelled by an air blast,
on metal, masonry, concrete, etc., to remove
dirt, rust, or paint, or to decorate the surface
with a rough texture.

sand boil The ejection of sand and water result-
ing from piping.

sand box See sand jack.

sand clay A mixture of sand and clay in
which the two materials have been blended so
their opposite qualities tend to maintain a
condition of stability with various moisture
contents.

sand-coarse aggregate ratio The ratio of
fine to coarse aggregate in a batch of concrete,
by either weight or volume.

846

sand interceptor

sand-dry Descriptive of a stage in drying of a

paint film at which sand will not adhere to the

surface.
sanded bitumen felt See asphalt prepared

roofing.
sanded fluxed-pitch felt A felt that is satu-
rated with a fluxed coal tar, coated with the

same material, and then sanded on both sides to

prevent sticking in the roll.
sanded grout Grout which incorporates fine

aggregate or sand into the mixture.
sanded plaster Gypsum plaster with sand

aggregate.
sand equivalent A measure of the amount of

clay contamination in fine aggregate.
sander l.A power sander. 2. A sanding

machine,
sand-faced brick A brick whose faces have

been sprinkled with sand before placing it in a

kiln at an elevated temperature.
sand filter A bed of fine sand which is laid over

graded gravel; used to remove impurities from a

water supply.

-UNDISTURBED EARTH
-TOPSOIL
'FILL MATERIAL
-UNTREATED BLDG.
PAPER

GRAVEL OR CRUSHED
STONE 8 FINE SAND

FILTER SAND

PERFORATED PIPE OR
DRAIN TILE WITH
OPEN JOINTS

sand filter: plan

sand filter trenches A system of trenches,
consisting of perforated pipe or drain tile sur-
rounded by clean, coarse aggregate containing
an intermediate layer of sand as filtering mate-
rial and provided with an underdrain for carry-
ing off the filtered sewage.

sand finish 1 . A textured-finish plaster surface;
the plaster contains sand, lime putty, and gaug-
ing or Keene's cement. 2. A finish obtained by
rubbing the coat to a smooth finish.

sand-float finish In plastering, a rough sand
finish obtained by using a wooden float.

DOSING TANK

TILE PIPE
WITH
TIGHT
JOINTS

FROM SEPTIC TANK

/ ^.ALTERNATING

SIPHON

DIVERSION BOXES

--MASONRY
WALL

DISTRIBUTION PIPE
ON 0.3% SLOPE

>rt- UNDERDRAIN
PIPE WITH
OPEN JOINTS

UNDERDRAIN
COLLECTOR PIPE
WITH BELLS
SPIGOT JOINTS

sand filter trench

sand grout, sanded grout Any portland
cement grout into which a fine aggregate is
incorporated.

sanding, flatting down, rubbing Smooth-
ing a surface with abrasive paper or cloth, either
by hand or by machine.

sanding block A device which holds a piece of
sandpaper for sanding by hand.

sanding machine A stationary, electrically
powered machine having a moving abrasive sur-
face (usually sandpaper); used for smoothing sur-
faces; the abrasive surface usually is a belt, disk,
or spindle. Also see power sander.

sanding sealer A priming coat which seals or
fills, without hiding, the grain of wood; a hard
film, usually sanded before the application of
subsequent coats.

sanding skip See skip.

sand interceptor, sand trap A small catch
basin designed and constructed to prevent the

- Cover

i— Grade

_^_

.*>.

Inlet

Water .

level

.(,'■

Water

Settlement
area for

sand

;¥ //////////# /,

■ Outlet

Masonry
pit

sand interceptor

847

sand jack

passage of sand (and other solids) into a drainage
system; requires periodic cleaning.

sand jack A box having tight joints which is
filled with dry, clean sand on which rests a tight-
fitting plunger; the plunger supports the bottom
of posts used in centering; when it is desired to
lower the centering, a plug in the bottom of the
box is removed, allowing the sand to run out.

sand-lime brick Brick made with sand and
slaked lime rather than with clay; usually a light
gray or off-white color.

sandpaper A tough paper which is coated with
an abrasive material such as silica, garnet, silicon
carbide, or aluminum oxide; used for smoothing
and polishing; graded by a grit numbering system
according to which the highest grit numbers
(360 to 600) are used for fine polishing, and the
lowest grit numbers (16 to 40) are used for coarse
smoothing. Alternatively, sandpaper may be
designated by the "0 grade" system, according to
which "very fine" includes grades from 10/0 to
6/0, "fine" from 5/0 to 3/0, "medium" 2/0, 1/0, K;
"coarse" 1, VA, and 2; "very coarse" 2 l A, 3, 3'A,
and 4.

sandpile A filling of compacted sand which has
been rammed into a hole left by a pile that has
been driven into the ground and then with-
drawn.

sand plate A flat steel plate which is welded to
the bottom of legs of bar-supports.

sand pocket A small region in mortar or con-
crete which contains fine aggregate, but little or
no cement.

sand-rubbed finish In stonework, a type of
surface formerly obtained by rubbing with a
sand-and-water mixture under a block; now such
a finish is obtained with a rotary or belt sander.

sand-sawn finish In stonecutting, a fairly
smooth surface resulting from using sand as the
abrasive agent carried by the gang saw blades.

sandstone Sedimentary rock composed of
sand-sized grains, naturally cemented by mineral
materials. In most sandstone used for building,
quartz grains predominate; often used for decora-
tive elements in buildings because it is easy to
carve.

sand streak A streak in the surface of formed
concrete; caused by bleeding, 4.

sand- struck brick See soft-mud brick.

sand trap See sand interceptor.

sandwich beam See flitch beam.

sandwich construction A composite con-
struction consisting of relatively thin layers of a
material (having high-strength properties)
bonded to a thicker, weaker, light core material;
results in high ratios of strength to weight and
stiffness to weight.

sandwiched girder Same as flitch beam.

sandwich panel A panel of sandwich con-
struction; made by bonding facing sheets, of
high strength and density, to a relatively light
core.

sanitary base, sanitary shoe A conge, usu-
ally associated with ceramic tile work.

sanitary bend A pipe bend having a radius
of curvature large enough to provide good
hydraulic-flow characteristics and prevent solids
from accumulating at the bend.

sanitary building drain A building drain
which conveys the discharge of plumbing fixtures.

sanitary building house sewer A building
sewer that carries sewage only.

sanitary cove On a stair, a metal piece serving
as a transition between the tread surface and the
riser face; used to facilitate cleaning.

sanitary cross A type of pipe cross used as a fit-
ting for a soil pipe; designed with a slight curve
in each of the 90° transitions so as to channel
flow from branch lines toward the direction of
the main flow.

sanitary cross

sanitary drainage Water and waste material
originating at plumbing fixtures, floor drains,
etc.

sanitary drainage fixture unit See fixture
unit.

sanitary engineering The application of en-
gineering to the control of environmental con-
ditions related to public health, such as water
supply, sewage, and industrial waste.

848

sarking felt

sanitary landfill Garbage that is buried to a
depth which is sufficient to control vermin,
odors, etc.

sanitary plumbing fixture Any receptacle
that receives or discharges water, liquid, or
water-borne waste from a W.C. or urinal into a
drainage system to which it is connected.

sanitary sewage, domestic sewage The
sewage containing human excrement or house-
hold wastes which originates in a water closet.

sanitary sewer A sewer which carries sewage
(liquid or waterborne waste from plumbing fix-
tures) and to which storm and surface water,
street runoff, and groundwater are not admitted
intentionally.

sanitary shoe Same as sanitary base.

sanitary stop See terminated stop.

sanitary tee A tee, 2 used as a fitting for a soil
pipe; designed with a slight curve in the 90°
transition so as to channel flow from a branch
line toward the direction of the main flow.

sanitary tee

sanitary ware Porcelain enamel ware, such
as bathtubs, sewer pipes, toilet bowls, wash-
basins, etc.

Santa Fe style An architectural mode that is a
combination of Pueblo Revival and Spanish
Colonial Revival architecture.

santorin A lightweight, gray, volcanic tuff; used
as pozzolan.

sap 1 . The fluid which circulates in trees, plants,
etc. 2. Same as sapwood. 3. See quarry sap. 4. To
dig a trench under a medieval fortress; used by
besiegers who were intent on blowing up an
enemy's defensive structure.

sapele, sapele mahogany A light-to-dark
red-brown wood of central and western Africa;
hard, relatively dense, frequently with ribbon-
stripe grain; often decoratively figured.

sap gum Wood of gum, 1 from either young
trees or the outer portion of logs.

sapling-frame construction Same as bent-
frame construction.

saponification The conversion into soap
which occurs when an alkali, such as the lime in
cement, reacts with oils in paint; destroys the
adhesion and strength of oil-based paint films.

sap stain l.Same as blue stain, 1. 2. A stain
used in wood finishing to make sapwood the
color of heartwood.

sapwood, alburnum The wood of a tree
between the bark and heartwood; normally lighter
in color than the heartwood; equal in strength to
heartwood but usually not as decay-resistant.

sapwood

Saracenic architecture Same as Muslim

architecture.
sarasin A portcullis.

sarcophagus An elaborate coffin for an impor-
tant personage, of terra-cotta, wood, stone,
metal, or other material, decorated with paint-
ing, carving, etc., and large enough to contain
only the body. If larger, it becomes a tomb.

sarcophagus of Roman Imperial time

sarking, sarking board 1. A thin board for
sheathing, laid under tiles or slating of a roof con-
struction. 2. (Brit.) Same as underlayment, 2.

sarking felt Same as underlayment, 2.

849

sarrasine

sarrasine A portcullis.

sash, window sash Any framework of a win-
dow; may be movable or fixed; may slide in a
vertical plane (as in a double-hung window) or
may be pivoted (as in a casement window); a
pivoted sash also is called a ventilator, 2.

sash adjuster Same as casement adjuster.

sash and frame A cased frame and a double-
hung window.

sash balance A spring-loaded device, usually a
spring balance or tape balance; used to counter-
balance a sash in a double-hung window; elimi-
nates the need for sash weights, sash cords, and
pulleys.

sash bar A secondary framing member to hold
panes within a window, a window wall, or a
glazed door; same as muntin.

sash block See jamb block.

sash casing Same as sash pocket.

sash center A support for a horizontally piv-
oted sash or transom; composed of two parts, a
socket which is attached to the frame or jamb,
and a pin on which the sash pivots.

sash center

sash chain A metal chain used to connect a
vertically hung sash with its counterweight; used
in place of a sash cord.

sash chisel A chisel having a wide blade,
sharpened on both sides; used for cutting the
mortises in pulley stiles.

sash cord, sash line In a double-hung win-
dow, a rope connecting a sash with its counter-
weight, passing over the sash pulley.

sash-cord iron A small metal holder inserted
in the edge of the sash of a double -hung window
to which sash cord or sash chain is attached.

sash counterweight See sash weight.

sash door See half-glass door.

sash fast, sash fastener, sash holder A fas-
tener, screw, or latch for holding two window
sashes together to prevent their being opened;
often attached to the meeting rails of a double-
hung window.

sash fast

sash fillister 1. A rabbet cut in a glazing bar to

receive the glass and glazing compound or putty.
2. A special plane for cutting such rabbets.

sash hardware All window accessories, in-
cluding sash chains or cords, sash fasteners, sash
lifts, sash weights, etc.

sash holder See sash fast.

sash lift See lift, 3; window lift.

sash chains

850

sateri roof

sash lift and hook, sash lift and lock A

sash lift having a locking lever which holds the
window fixed by means of a strike in the window
frame; raising the sash releases the strike.

sash line A rope by which a sash is suspended
in its frame; also called a sash cord.

sash lock l.A sash fast. 2. A sash fast con-
trolled by a key. 3. An upright mortised lock.

sash plane A carpenter's plane for trimming
the inside of a window frame or doorframe; has a
special notched cutter.

sash plate In a horizontally pivoted sash or
transom, one of a pair of plates providing the
pivot mechanism.

sash pocket See pocket, 2.

sash-pole socket, sash socket A metal
plate attached to a sash (or a transom) which is
beyond hand reach; the sash can be raised or
lowered by means of a pole having a hook at the
far end, which is inserted in the socket.

sash pull A small metal plate sunk in a sash rail,
or a handle attached to the rail, for raising or
lowering the sash.

sash pulley, axle pulley In a double-hung
window, a pulley mortised into the side of the
frame near the top; the sash cord or sash chain
passes over this pulley to the counterweight.

sash pulley

sash ribbon A metal tape used in place of a

sash cord,
sash run See pulley stile.
sash saw A small saw, similar to but smaller

than a tenon saw, used for cutting the tenons of

sashes.
sash sill See sill, 3.
sash socket Same as sash-pole socket.
sash spring bolt See window spring bolt.

sash stop A small strip nailed or screwed around
a cased frame to hold a sash (of a double-hung
window) in place; also called a window stop.

sash stuff Wood which has been cut to stock
sizes and shapes and prepared for making win-
dow frames.

sash tool A round brush used for painting
frames, glazing bars, and other details of sash
windows.

sash weight, sash counterweight A weight
(usually of cast iron) used to balance a vertically
sliding sash.

sash 'window Any window having a sliding
(vertically or horizontally) or hung sash, but
usually a double-hung window.

Sassanian architecture Architecture preva-
lent in Persia under the Sassanian dynasty (3rd
to 7th cent. A.D.); excelled in large palace com-
plexes with open iwans and the extensive use of
barrel vaults and parabolic domes on squinches
of brick or rubblestone, set in plaster mortar and
constructed without centering. The massive
walls were covered with stucco decor or articu-
lated by pilasters and cornices.

Sassanian architecture gallery in palace at Serhistan

satellite community A relatively small town,
primarily residential, established in the vicinity
of a city of much greater size; sometimes called a
bedroom community.

sateri roof In Swedish architecture of the
17th and 18th centuries, a type of hipped roof
with vertical breaks which were often provided
with windows.

851

satin finish

satin finish See scratch-brushed finish.

satin paint A paint having a low-gloss finish.
satin sheen The subdued gloss of a paint film.
satinwood A hard, fine-grained, pale to golden

yellow wood of the gum arabic (acacia gum)

tree; esp. used in cabinetwork and decorative

paneling.
satisfaction Cancellation of an encumbrance

on real property, usually by payment of the debt

secured by it.

satisfaction piece A document, prepared
and executed in such manner as to be appropri-
ate for recording in real estate records, evidenc-
ing the fact that an encumbrance has been
discharged.

saturant In roofing, a bituminous material,
having a low softening point, used for impreg-
nating the felt in asphalt prepared roofing.

saturated air Air containing the maximum
amount of water vapor possible at a given tem-
perature; the partial pressure of the water vapor
is equal to the vapor pressure of water at the
same temperature.

saturated color See saturation, 2.

saturated felt, saturated roofing felt See
asphalt prepared roofing.

saturated surface dry The condition of an
aggregate particle or other porous solid when the
permeable voids are filled with water but the
exposed surfaces are dry.

saturated vapor pressure The pressure
above a liquid at constant temperature which is
confined so that the vapor from the liquid accu-
mulates above it; the value depends on the tem-
perature and the properties of the liquid.

saturation 1 . The condition under which air at
a given temperature and pressure holds the max-
imum amount of water vapor without causing
precipitation. 2. The degree of purity of a color.
A color is said to be saturated when it contains
no white.

saturation coefficient See C/B ratio.

saturation line A line indicating the ground-
water level.

saturation temperature The air temperature
at which, for any given water vapor content, the
air is saturated; any further temperature reduc-
tion results in condensation.

saucer dome A dome that is very shallow; its
radius of curvature of the dome is very large
compared with its rise.

sauna A steam bath, of Finnish origin, in which
steam is produced by spraying water on very hot
stones; in some modern units, heated surfaces
other than stone are used.

sausage compactor A type of refuse com-
pactor; Same as extruded compactor.

savino 1 . One of many saplings used in roof
construction in pueblo architecture; such
saplings are laid across the roof beams (vigas) to
provide support for fiber matting, then covered
by a thick layer of earth or dried mud that acts as
a roof. 2. Red cedar posts once used in Spanish
Colonial homes.

saw A cutting tool having a thin, flat metal
blade, band, or stiff plate with cutting teeth
along the edge; worked either by a reciprocating
motion (as in a handsaw) or by a continuous
motion (as in a band saw).

saw bench A bench on which a circular saw is
mounted.

sawbuck See sawhorse.

sawdust concrete A concrete made of a mix-
ture of sawdust and concrete.

sawed finish, sawn face The surface of any
stone which has been sawn, e.g., sand-sawn,
shot-sawn, etc.

sawed joint In hardened concrete, a joint cut
by means of special silicon-carbide or diamond
blades; generally not to the full depth of the
member.

sawed-log house See board house, 1.

sawhorse, sawbuck A four-legged support,
usually used in pairs, to hold wood while being
sawed.

852

scaffold

saw kerf A kerf, 2, or slot, which is cut into

wood by a saw.

sawmill A facility where timber is sawn by
mechanical equipment into boards and planks.
Many early sawmills were operated by power
generated by rivers, streams, or tidal changes.
The development of the gang saw, which con-
tained several parallel saw blades in a single
frame greatly enhanced their efficiency; this
innovation was followed by the invention of the
circular saw. Virtually all saws are now operated
by electric power.

sawn face See sawed finish.

sawn-log house Same as board house.

sawn veneer A strong, high-quality veneer cut
with a thin saw, rather than sliced or rotary-cut.

sawpit A pit dug in the ground and usually lined
with boards, over which a log to be sawn was laid
during a hand-sawing operation; often located
on the side of a hill, for accessibility.

saw set An instrument used to set or angle the
teeth of a saw blade so as to make a kerf wider
than the thickness of the blade in order to
reduce friction.

saw table The table or platform of a powered
saw, on which the material to be sawn is held or
clamped during the sawing.

saw-tooth frieze Same as dog-tooth frieze.

sawtooth molding Same as notched molding.

sawtooth pattern On a roof, a pattern of tiles
or shingles resembling the teeth of a saw.

sawtooth roof A roof system having a number
of parallel roof surfaces of triangular section with
a profile similar to the teeth in a saw; usually the
steeper side is glazed and often faces north.

section through a sawtooth roof

sawtooth skylight A skylight in the steeply

inclined surface of a sawtooth roof.
sax, slate ax A slate cutter's hammer; has a
point at the back of the head for making nail
holes in the slate.

Saxon architecture See Anglo-Saxon archi-
tecture.

Saxon shake A long shingle made of red cedar,
usually of random width and butt, 2 thickness.

sb Abbr. for stilb.

SBCCI Abbr. for "Southern Building Code
Congress International," which publishes the
Standard Building Code.

SB rubber See styrene-butadiene rubber.

scab A short flat piece of lumber which is

bolted, nailed, or screwed to two butting pieces
in order to splice them together.

scabbing hammer See scabbling hammer.

scabble To dress stone with a pick, scabbling
hammer, or broad chisel, leaving prominent
toolmarks so that a rough planar surface results;
usually preparatory to finer dressing.

scabbled rubble In masonry, rubble which has
had only the roughest irregularities removed.

scabbling A chip or fragment of stone.

scabbling hammer, scabbing hammer A
hammer with one end pointed for picking a
stone; used for rough dressing.

scabellum In Roman architecture and deri-
vates, a high, freestanding pedestal.

scaena A temporary building or booth for play-
ers behind the acting area in the ancient the-
ater; later the permanent back building of the
theater.

scaena ductilis In the ancient theater, a mov-
able screen which served as a background.

scaenae frons See frons scaenae.

scaffold l.A temporary platform to support
workers and materials on the face of a structure
and to provide access to work areas above the
ground. 2. Any elevated platform.

853

scaffold board

scaffold board One of the boards that form
the work floor of a scaffold.

scaffold height The distance between succes-
sive stages of scaffolding used in masonry con-
struction; usually about the height within which
a bricklayer can work effectively.

scaffold-high Descriptive of masonry con-
struction work sufficiently high to require a
scaffold.

scaffold nail See double-headed nail.

scagliola Plaster work imitating stone, in which
mixtures of marble dust, sizing, and various pig-
ments are laid in decorative figures; designs may
be routed into a surface.

scale l.The product resulting from the corro-
sion of metals. 2. A heavy oxide coating on cop-
per and copper alloys resulting from exposure to
high temperatures in an oxidizing atmosphere.
3. In drawing, a measuring instrument with
graduated spaces. 4. A system of proportion by
which definite magnitudes represent defined
larger magnitudes, as on a map or drawing. 5.
See scaling. 6. The outer covering of a casing.
7. See architect's scale, engineer's scale. 8. The
crust on the inner surfaces of boilers, hot water
heaters, and pipes formed by deposits of silica
and other contaminants in water.

scaleboard Thin sheet of wood used for veneer.

scale drawing A drawing, usually considerably
reduced in size from the actual or designed
object, site, construction, or building, but which
is drawn to scale, 4.

scale ornament Same as imbrication.

scaling Local flaking or peeling away of the sur-
face portion of concrete or mortar.

scallop One of a continuous series of curves
resembling segments of a circle, used as a deco-
rative element on the outer edge of a strip of
wood, molding etc.

scalloped capital The term applied to a
medieval block (cushion) capital when each
lunette is developed into several truncated

cones.

scalloped capital

scalper A screen for removing oversize particles.

scalping The removal of particles larger than a
specified size by screening.

scalp rock Rock which has passed over a grad-
ing screen and has been rejected; waste rock.

scamillus l.In Classical and Neoclassical
architecture, a plain block placed under the
plinth of a column, thus forming a double plinth.
2. A slight bevel at the outer edge of a block of
stone, as occurs between the necking of a Doric
capital and the upper drum of the shaft.

scallops: a scalloped molding

scamillus, 1

Scamozzi order An order similar to the Ionic
but having volutes of the capital which radiate
at 45°.

scant Said of lumber, panels, etc., somewhat
short of a specified dimension; bare.

scantle, gauge stick, size stick In roofing, a
gauge by which slates are cut to proper length.

scantling 1. A piece of square-sawn timber VA
in. (47.6 mm) to under 4 in. (101.6 mm) thick,
and 2 in. (50.8 mm) to under 4M in. (114-3 mm)

854

scheme

wide. 2. Hardwood timber cut to specified
dimensions. 3. Any square-edged piece of hard-
wood of nonstandard dimensions.

scape Same as apophyge.

scapple Same as scabble.

scapulary tablet In Zapotec architecture of

Mesoamerica, a rectangular framed panel can-
tilevered over an outward-sloping apron.

scapus The shaft of a column.

scarcement In building, a setback in the face
of a wall, or in an earthen embankment; a foot-
ing or ledge formed by the setting back of a wall.

scarf 1 . The end on one of the pieces of timber
forming a scarf joint. 2. A scarf joint.

scarf connection Same as scarf joint.

scarf joint 1. A joint by which the ends of two
pieces of timber are united to form a continuous
piece; the mating surfaces may be beveled,
chamfered, notched, etc., before bolting, gluing,
welding, etc. 2. A joint formed by bonding the
beveled ends of two pieces of lumber. 3. In weld-
ing, a butt joint between two pieces whose ends
are beveled. 4. A joint in electrical cable in
which the ends are beveled before soldering.

■*

«r

scarf joint, 1

scarifier A machine or an attachment for a
tractor or grader having a long tooth or series of
teeth that can be lowered to tear up surface soil
or pavement.

■ifier

scarify To roughen a surface by sanding or some
other technique, in order to improve adhesion of
paint.

scarp A steep slope constructed as a defensive
measure in a fortification.

SC asphalt Same as slow-curing asphalt,
scena Same as scaena.

scene dock A place usually adjacent to, or
below, the stage of a theater where the scenery is
stored.

scenery Any or all devices ordinarily used on a
theater stage, such as backdrops, borders, scrims,
set pieces, side tabs, tabs, but not including props
or costumes.

scenery wagon (Brit.) boat dock A low
platform on casters or rollers, used to support
scenery on the stage of a theater; permits rapid
changes of scenery.

scene shop A place where scenery is fabricated
for use in a theater or opera house.

scent test, smell test A test for leaks in a
drainpipe; a material having a strong odor is
introduced into the pipe and leaks are detected
by tracing the scent to its source.

sceuophylacium Same as diaconicon, 1.

SCH On drawings, abbr. for "schedule."

schedule l.A detailed tabulation of compo-
nents, items, or parts to be furnished, as a door
schedule. 2. See steel pipe.

scheduled maintenance Same as preventa-
tive maintenance.

schedule of defects Same as punch list.

schedule of values A statement furnished by
the contractor to the architect reflecting the
portions of the contract sum allotted for the var-
ious parts of the work and used as the basis for
reviewing the contractor's applications for
progress payments.

schematic design phase The first phase of
the architect's basic services. In this phase, the
architect consults with the owner to ascertain
the requirements of the project and prepares
schematic design studies consisting of drawings
and other documents illustrating the scale and
relationship of the project components for
approval by the owner. The architect also sub-
mits to the owner a statement of probable con-
struction cost.

schematic drawing See schematic design
phase.

scheme l.The basic arrangement of an archi-
tectural composition. 2. Preliminary sketch for a
design.

855

scheme arch

scheme arch An arch which forms part of a
circle which is less than a semicircle.

schist A rock, the constituent minerals of
which have assumed a position in more or less
closely parallel layers or folia; due to metamor-
phic action; used principally for flagging.

schola l.The apse or alcove containing a tub
in Roman baths. 2. An exedra or alcove in a
palaestra for relaxation or conversation. 3. At
the head of the nave of a church, the space
set aside for the choir. Also called a schola
cantorum.

school An educational institution offering
studies at differentiated levels to groups of pupils
of various ages; instruction may be given by one
or more teachers. It may be contained in a single
structure or a group of separate buildings; may be
under private or public auspices.

schoolhouse A building in which classes are
conducted at different educational levels for
students up to college age. Also see one-room
schoolhouse.

sciagraph The geometrical representation of a
building, showing its interior structure or
arrangement.

scialbo Same as intonaco.

scima Same as cyma.

scimatium Same as cymatium.

scintled brickwork Same as skintled brick-
work.

scion A cutting from a woody plant that is
joined onto rootstock of another plant in graft-
ing and budding.

scissors truss A type of truss used to support a
pitched roof; the ties cross each other and are

connected to the opposite rafters at an interme-
diate point along their length.

sclerometer An instrument for determining
the degree of hardness of a material by the
amount of pressure required to scratch it with a
diamond point.

scoinson arch Same as sconcheon arch.

scollop Same as scallop.

scollop capital In Romanesque architecture, a
capital similar to a cushion capital but having its
underside scalloped.

sconce 1. An electric lamp, resembling a can-
dlestick or a group of candlesticks, which is
designed and fabricated for mounting on a wall.
2. In medieval architecture, a detached earth-
work, 2 that serves as a small defensive position,
providing additional protection for a fort.

sconcheon, esconson, scuncheon l.The
reveal of an aperture (such as a door or window)
from the frame to the inner face of the wall.
2. See squinch, 2.

sconcheon arch, scoinson arch An arch
which includes the sconcheons of a door or
window.

scissors truss

sconcheon arch

scone Same as split, 3.

scoop loader Same as front-end loader.

scorched finish A surface finish of an igneous
or siliceous rock that has been heated with a
blowtorch, causing the surface to form small
craters.

score 1 . To cut a channel or groove in a material
with a hand tool or a circular saw so as to inter-
rupt the visual effect of a surface or otherwise
decorate it. 2. To roughen the surface of a mate-
rial with gouges to provide a better bond for
mortar, plaster, or stucco; to scratch. 3. To
groove a freshly placed concrete surface with a
tool to control shrinkage cracking. 4. To
roughen the top surface of one concrete pour in

856

scratcher

order to provide a better mechanical bond for
the next pour.

scored block A masonry block having grooves
on its surface.

scored finish A characteristic of a building
unit having faces which have been grooved dur-
ing the manufacturing process.

scored joint Same as scribed joint, 2.

scoria 1. A dark, cellular volcanic rock. 2. Blast-
furnace slag or scum.

scotch See scutch.

Scotch bond Same as common bond.

Scotch bracketing Lath, attached at an angle
between a wall and ceiling, which form a base
for a hollow cornice.

Scotch glue An animal glue.
scotching Same as scutching.
Scotch method of application See Dutch
method of application.

scotia A deep concave molding, esp. one at the
base of a column in Classical architecture. Also
called a gorge, trochilus.

scour The erosion of a concrete surface, expos-
ing the aggregate.

scouring Using a wood float, in a circular
motion, to smooth freshly applied mortar or
plaster.

scouring action In a drain pipe, the lifting or
scrubbing of loose particles (including sand, grit,
and small pebbles) from the interior surface of
the pipe and carrying them downstream. To
achieve this action, sufficient flow velocity is
required.

SCPI Abbr. for "Structural Clay Products

Institute."
SCR Abbr. for "silicon-controlled rectifier."
scrabbled rubble Same as rubblework.

scraped finish A European style of plaster fin-
ish which is obtained by scraping the stucco fin-
ish coat with a steel tool (sometimes serrated) as
the stucco is setting.

scraped joint A joint brought to an accurately
plane surface by scraping.

scraper 1. A self-propelled machine capable of
digging, loading, hauling, dumping, and spread-
ing materials; used to move earth by stripping or
collecting a layer with a cutting blade while
moving forward, pushing the earth into a bowl,
and then unloading it. 2. A towed machine
which is used to level the surface of ground by
stripping away earth, or by collecting earth and
filling hollow areas. 3. A cabinet scraper.

pull-type scraper, 1

scraper plane Same as cabinet scraper.
scratch To score or groove a plaster surface to

provide a better bond for the succeeding coat.
scratch awl An awl used for scribing wood,

plastic, or the like.

scratch awl

scratch-brushed finish, satin finish A fin-
ish obtained by mechanically brushing a surface
with wire bristle brushes or by rotary buffing
with an abrasive compound.

scratch coat In three-coat plastering, the first
coat of plaster, which is then scratched to pro-
vide a bond for the second (brown) coat.

scratched Said of a surface in which minute
groove-like breaks are made in the surface.

scratcher See scratch tool.

857

scratch tool

scratch tool, scratcher Any hand tool for
scratching plaster to provide a mechanical bond
for the following coat of plaster, such as a drag or
devil float.

scratchwork Same as sgraffito.

SCR brick Brick whose nominal dimensions
are 2.67 in. by 6 in. by 12 in. (6.8 cm by 15.3 cm
by 30.5 cm).

screed 1. Firmly established grade strips or
side forms for unformed concrete which will
guide the strikeoff in producing the desired
plane or shape; also called screed rail. 2. A tool
to strike off the concrete surface. 3. A long,
narrow strip of plaster, applied at intervals on a
surface to be plastered; carefully leveled and
trued to act as a guide for plastering to the
specified thickness. 4. A layer of mortar laid
on concrete, usually to provide a uniform,
level surface.

screed coat In plastering, a coat made even or
flush with the screeds.

screeding Forming a concrete surface by use of
screeds and a strikeoff.

screed rail See screed, 1.

screed strip A screed, 3.

screed wire Same as ground wire, 2.

screen l.Any construction whose essential
function is merely to separate, protect, seclude,
or conceal, but not to support. 2. A covered
framework, either fixed or movable, that serves
as a protection against sun, fire, wind, rain,
cold, or insects. 3. A metallic plate or sheet, a
woven wire cloth, or other similar device, with
regularly spaced apertures of uniform size,
mounted in a suitable frame or holder for use in
separating material according to size; also called
a sieve.

screen analysis See sieve analysis.

screen block»wall The use of concrete masonry
units primarily as a screen wall.

screen door A lightweight exterior door con-
sisting of solid wood or aluminum stiles and rails
that serve as a framework for small-mesh wire
screening; permits ventilation but excludes
insects.

screen-door latch A small locking or latching
device used on screen doors and operated by a
knob or a lever handle; sometimes equipped
with a dead bolt.

screen-door

latch

screen facade A nonstructural facing assem-
bly used to disguise the form or dimensions of a
building.

screenings In passing sand or aggregate
through a sieve, that portion which is retained
on the sieve.

screen molding Any type of simple molding
used to cover the exposed edge of a sheet of wire
screening.

screen side Of a fiberboard or the like, that
side which receives the impression of the mesh
during manufacture.

screens passage In a medieval hall, 1, a
wooden screen placed in front of the doors that
led to the kitchen or buttery so as to block them
from view.

screen tile A clay tile made for a screen wall of
masonry construction.

screen wall A screen of some solidity as differing
from one which is pierced, esp. in the intercolum-
niations of a colonnade. Also see pierced wall.

screen wire cloth A light wire cloth used as
screening in a door or window.

screw An externally threaded fastener.

ROOT-

CREST-

DEPTH OF THREAD —i

SCREW / \

THREAD
ANGLE

NUT

EXTERNAL

INTERNAL

THREAD

screw:

nomenclature

858

scroll molding

screw anchor An anchor (similar to an
expansion bolt) having a metal shell with a
screw along its central axis; when the shell is
placed in a hole and the screw is driven in, the
shell expands, tightly securing the anchor in the
hole.

screw auger Same as auger, 1.

screw blank See bolt blank.

screw clamp Any clamp set by means of a
screw, but esp. one used in woodworking which
has two large parallel jaws for holding the work
to be pressed together.

screw clamp

screw dowel A metal dowel pin provided with
a straight or tapered thread.

screw dowel

screwdriver A tool having a handle and a long
shank, with a tapered wedge-shaped tip which
fits into the recess in the head of a screw; used
for driving a screw in place or removing it, by
turning the head of the screw.

screwed joint A joint that uses threads on the
ends of two pipes (or on a pipe and a fitting) to
draw the two pieces together and form a
leakproof seal.

screwed 'work In wood turning, work in
which the cutting is done in a spiral direction, so
as to leave a spiral fillet or other ornamental spi-
ral pattern.

screw eye A screw having a loop or eye for its
head.

screw jack Same as jackscrew.

screwless knob A doorknob attached to a
spindle by means of a special wrench instead of
the more commonly used side screw.

screwless rose A rose with a concealed method
of attachment.

screwnail See drivescrew.

screw pile 1. A pile which has a broad-bladed
screw attached to its foot to provide a larger
bearing area. 2. A pile which has a spiral blade
fixed to its lower end; it is twisted into the
ground rather than driven by a series of impacts.

screw shackle Same as turnbuckle.

screw stair, winding stair A circular stair
whose steps wind around a central post. Also
called a newel stair or vice stair.

screw thread See thread and taper thread.

scribbled ornament A decorative effect pro-
duced by lines, scrolls, or the like, irregularly dis-
tributed over a surface.

scribed joint 1. See coped joint. 2. A masonry
joint in which a thin line has been cut in the
face of the mortar between bricks after it has
been smoothed with a metal tool.

scriber A pointed instrument used to mark lines
on wood, metal, bricks, etc., to serve as a guide
in sawing, cutting, etc.

scrim l.A coarse mesh- like material such as
heavy cloth, fiberglass, or wire mesh, used to
bridge and reinforce a joint or as a base for plas-
tering or painting. 2. A light open-weave fabric,
sometimes painted or dyed, used as a drop cur-
tain or part of a drop curtain; transparent, but
less so than theatrical gauze.

scriptorium A writing room; specifically, the
room assigned in a monastery for the copying of
manuscripts.

scroll An ornament consisting of a spirally
wound band, either as a running ornament or as
a terminal, like the volutes of the Ionic capital
or the scrolls on consoles and modillions.

scroll molding A form of roll molding; a large
projecting molding, resembling a scroll with the

859

scroll pediment

scroll molding

free end hanging down, found in string-courses
and similar locations requiring a drip. Also see
torsade, 1 .

scroll pediment A little-used synonym for
swan's-neck pediment.

scroll saw A handsaw or band saw for cutting
thin boards, veneers, or plates into ornamental
scrollwork; esp. used for cutting curves.

scroll step See curtail step.

scrollwork 1 . Ornamental woodwork that has
been cut by a scrollsaw in decorative curved pat-
terns often suggestive of a series of waves. 2.
Wrought-iron ornamental work in which scroll-
like characters are an important element.

scrubboard A baseboard.

scrub plane A plane having a blade with a
rounded cutting edge; used in rough carpentry
work.

scrub sink A plumbing fixture usually located
in the operating suite in a hospital to enable per-
sonnel to scrub their hands prior to a surgical
procedure; the hot and cold water supply is acti-
vated by a knee-action mixing valve or by wrist
or pedal control.

scullery A room, generally annexed to a
kitchen, used to prepare food for cooking, and/or
as a pantry.

scum, scumming l.A surface deposit some-
times formed on clay bricks; caused either by sol-
uble salts in the clay which migrate to the
surface as moisture escapes during drying (drier
scum) or by the formation of deposits during
kiln firing (kiln scum). 2. A mass of organic
matter which floats on the surface of sewage.

scumbling In painting, the operation of lightly
rubbing a brush containing a small quantity of
opaque or semiopaque color over a surface to
soften and blend tints that are too bright, or to
produce a special effect; the coat may be so thin
as to be semitransparent.

scuncheon Same as sconcheon.

scupper 1 . An opening in a wall or parapet that
allows water to drain from a roof. 2. A device

scupper, 2

placed in such an opening to prevent clogging of
the drain.

scupper drain Same as scupper.

scutch, scotch A bricklayer's tool, with a cut-
ting edge on each side, for cutting, trimming,
and dressing brick or stone.

scutcheon Same as escutcheon.

scutching A method of finely dressing stone
with a hammer, the head of which is composed
of a bundle of steel points.

scuttle A hatchway or opening through a roof-
deck or ceiling for access purposes, with a lid for
covering it.

scuttle door A door covering a scutde in a
roof; usually made of sheet metal with a metal
frame; often hinged and counterbalanced.

scutula A segment of marble or other material,
cut in the shape of a diamond or rhombus and
used for inlaying floors or pavements.

SDFU (sanitary drainage fixture unit)
See fixture unit.

Sdg Abbr. for siding.

SDR See standard dimension ratio.

S/E Abbr. for "square-edged."

SE&S In the lumber industry, abbr. for "square
edge and sound."

seal l.A device usually consisting of an impres-
sion upon wax or paper, or a wafer, or the
inscription of the letters "L.S." (locus sigilli),
sometimes used in the execution of a formal
legal document such as a deed or contract. In
some states, the statute of limitations applicable
to a contract under seal is longer than that for a
contract not under seal; in most states, the seal
has been deprived by statute of some or all of its
legal effect. 2. An embossing device or stamp
used by a design professional on his drawings
and specifications as evidence of his registration
in the state where the work, 1 is to be performed.

860

seat

INLET

OUTLET

seal, 4

3. In a trap for a plumbing fixture, the water
between the dip and the crown weir; a water
seal. 4. The vertical distance between the dip
and the crown weir of a trap. 5. To coat the sur-
face fibers of wood so as to prevent penetration
of moisture or successive coatings during finish-
ing. 6. To apply a shellac or other resin-resistant
coating on knots in wood, to prevent resin stain-
ing; to kill. 7. A sealant; a sealer.

sealable equipment Electrical equipment
enclosed in a case or cabinet that is provided
with a means of locking or sealing so that live
parts are not accessible unless the enclosure is
opened.

sealant Any material or device used to prevent
the passage of liquid or gas across a joint or open-
ing; a sealer.

sealant backing A compressible material
inserted in a joint prior to applying a sealant;
limits the depth of the sealant.

seal coat, sealing coat Same as sealer.

sealed glass unit Same as insulating glass unit.

sealed hot-water system A hot-water heat-
ing system that has no expansion tank above the
heating tank; i.e., the system is completely
sealed.

sealed refrigeration compressor A me-
chanical compressor consisting of a compressor
and a motor, both enclosed in the same sealed
housing, with no external shaft or shaft seals,
the motor operating in the refrigerant atmo-
sphere.

sealer 1 . A liquid coat which seals wood, plaster,
etc., and prevents the surface from absorbing
paint or varnish; may be transparent; may act as
a primer for a following coat or as a finish for the
surface. 2. A coat, applied in liquid form, which
is laid over a tar-like substance to prevent its
bleeding through an applied paint film. 3. A

finishing coat of a bituminous substance, asphalt,
concrete, etc., to seal it against moisture.

sealing compound A mastic-like material
used as a seal or sealer.

sealing sleeve Same as compression coupling.

sealing tape A preformed, uncured, or partially-
cured material that meets ASTM requirements
for the adhesive and cohesive properties required
for forming a sealed joint.

seal weld A weld used primarily to provide a
specific degree of tightness against leakage.

seam 1. A joint between two sheets of materi-
als, such as metal. 2. See welt.

seamer A hand tool used in making sheet-
metal joints or seams.

seam face On a building stone, a face formed
by a natural seam in the rock.

seaming The joining of the edges of a metal
sheet or sheets by bending over or doubling and
pinching them together.

seamless door 1. A hollow-metal door formed
from two sheets of steel, without seams on the
door faces or on the vertical edges. 2. A steel
door of composite construction; the sheet-steel
facings are bonded to a solid, structural mineral
core without edge seams.

seamless floor See polymeric poured floor.

seamless flooring Fluid or trowel-applied
flooring without aggregates.

seamless pipe Pipe without a longitudinal joint

or seam.
seamless tubing Tubing having a continuous

periphery, with no longitudinal seam.
seam roll Same as hollow roll,
seam weld A continuous weld made along a

line between two overlapping members.
season crack 1. A crack that develops in met-
als that have been rolled or otherwise subjected

to a process developing internal stress. 2. Same

as seasoning check.
seasoning 1 . The drying of wood, either in air or

in a kiln. 2. The curing or hardening of concrete.
seasoning check A longitudinal crack that

develops in wood during the drying process as a

result of uneven or rapid seasoning.
seat l.In carpentry, same as seat cut. 2. In

plumbing, same as valve seat.

861

seat angle

seat angle A short angle iron connected to a
column to support a beam temporarily during
erection.

seat cut A horizontal cut at the lower end of a
rafter so that it may rest securely on the edge of
a horizontal timber such as a wall plate; also see
illustration for bird's mouth.

CEILING JOISTS
RAFTERS

seating 1. Devices such as theater seats,
benches, pews, etc., used for the accommodation
of groups of people. 2. The arrangement of seats
in a place of assembly. 3. The capacity of a room
or space in terms of the number of seats avail-
able; the seating capacity.

seating capacity The total number of seats in
an auditorium.

seating section A group of seats bounded on
all sides by aisles, ramps, walls, or partitions.

sec Abbr. for "second."

secco See fresco secco.

second A unit of secondary quality or one not
meeting specified dimensions; a cull.

secondary air 1 . Air which is introduced into
a furnace (in addition to the primary air which
enters either as a mixture with fuel or as blast
underneath a stoker) above or around the
flames to promote combustion. 2. Air already in

an air-conditioned space, in contrast to primary
air which is introduced into the space.

secondary air motion The motion of air in a
room caused by the discharge of air from an air
diffuser or any type of air outlet.

secondary arch See rear arch.

secondary beam A beam which is carried by
the main beams and transmits its load to them.

secondary blasting The reduction of oversize
material by the use of explosives to the dimen-
sion required for handling, including mudcap-
ping and blockholing.

secondary branch In plumbing, any branch
of a building drain or water-supply main other
than a primary branch.

secondary combustion The unintentional
combustion of fuel beyond the outlet of a
furnace.

secondary consolidation The reduction in
volume of a soil mass caused by the application
of a sustained load to the mass, due principally
to the adjustment of the internal structure of
the soil mass after most of the load has been
transferred from the soil water to the soil
solids.

secondary distribution feeder In electric
wiring systems, a feeder which operates at the
secondary voltage supplying a distribution cir-
cuit.

secondary exit An alternative exit, not neces-
sarily required by code.

secondary facade A facade not facing a pub-
lic street or otherwise visible to the public, and
that does not possess significant architectural
features.

secondary feeders Electrical conductors be-
tween the main distribution center at the build-
ing service entrance and the distribution centers
downstream (i.e., closer to the load).

secondary glazing Any glazing added to an
existing window, that forms a double window.

secondary light source l.A light source
which is not self-luminous but receives light and
redirects it as by reflection or transmission.
2. The second most important, or most obvious,
source of light when several sources are present.

secondary member See secondary truss
member.

862

secret dovetail

secondary reinforcement In reinforced
concrete, any steel reinforcement other than
main reinforcement.

secondary school See high school.

secondary substation Same as distribution
center.

secondary truss member A subsidiary mem-
ber of a truss, used to support a main member or
to transfer load from a point within a panel to
one or more panel points.

secondary voltage Low voltage, distributed
to the different circuits within a building.

Second Classical Revival style A term
sometimes used as a synonym for Italian Renais-
sance Revival.

second coat In plastering, the brown coat; in
two-coat work, the finish coat.

Second Empire architecture A stylistic
designation for the eclectic architecture named
after the French Second Empire of Napoleon III
(1852-1870) or their derivatives.

Second Empire style in the United States

A grand, eclectic architectural style from about
1855 to 1890 and beyond, primarily in public
buildings but also in domestic architecture;
named after the French Second Empire of
Napoleon III (1852-1870); frequently called
Mansard style because it features a mansard roof
usually having the profile of a compound curve.
Buildings in this style usually are characterized
by the following attributes: a central one-story
pavilion projecting outward from a facade; clas-
sical pediments with elaborate heavy detailing
and trim; often, a heavy cornice, typically sup-
ported by decorative brackets; commonly, a
square tower located at the center of the facade;
pedimented dormers; terneplate or multicolored
slates forming decorative patterns covering the
roof; a curb or railing around the roof, com-
monly enclosed with decorative metalwork
cresting; windows having an upper sash divided
in two parts by a vertical secondary framing
member, over a similar lower sash; pedimented,
bracketed, or hooded windows usually having
square or arched heads; tall, almost floor-to-
ceiling windows on the first floor; a pair of pan-
eled entry doors having glass in the upper
panels; frequently, arched doorways; usually,
steps leading from the street up to the level of

Second Empire style

the doorway. Also called General Grant style or
Second Empire Baroque.

second fixings All carpentry and joinery
installed after the plastering; may include elec-
trical wiring and plumbing.

second-growth timber Wood which has
grown after a virgin forest has been cut down.

Second Period Colonial architecture A
term occasionally applied to American Colonial
architecture during the period from about 1700
to 1776.

Second Pointed style Same as Decorated
style, the second of three phases of English
Gothic architecture.

Second Renaissance Same as Italian Renais-
sance Revival.

secos Same as sekos.

secret dovetail, miter dovetail A joint
appearing to be a simple miter joint when
assembled, but having dovetailing concealed
within it.

secret dovetail

863

secret fixing

secret fixing See secret screwing.

secret gate latch A spring latch which is

surface-mounted on an office gate (or the like);

operated by a concealed button or actuated

electrically.
secret gutter A concealed gutter.
secretium A sacristy.

SectionFormat A three-part format for orga-
nizing building specifications into sections,
according to the Construction Specifications
Institute.

secret joggle An interlocking joint in an ash-
lar voussoir that is not visible on the face.

secret nailing See blind nailing.

secret room A room, often in a garret, whose
entrance is hidden.

secret screwing, secret fixing, secret screw
joint A method of joining carpentry work by
screws which are hidden.

secret tenon Same as stub tenon.

secret valley See secret gutter.

SECT On drawings, abbr. for "section."

sectile opus A kind of pavement formed of
slabs or tiles of glass or other material, the pieces
having a uniform size (far larger than the
tesserae of ordinary mosaic) and being either
plain-colored or mottled and veined.

sectile opus (two types)

section l.A representation of an object as it
would appear if cut by an imaginary plane, show-
ing the internal structure. 2. A representation of
a building, or portion thereof, drawn as if it were

I— -A

PERSPECTIVE VIEW
section, 2

cut vertically to show the interior. 3. Such a rep-
resentation of a molding or assembly of pieces, to
show the profile or makeup. 4. In structures, a
section made by a plane perpendicular to the
axis of a member, structure, or any construction.
5. A subdivision of a division of the specifica-
tions which covers the work of no more than
one trade.

sectional insulation Thermal insulation fab-
ricated in sections which fit together, such as
molded pipe insulation made of two or more
annular segments.

sectional ladder A portable ladder that is not
self-supporting and not adjustable in length;
consists of two or more sections of ladder that
may be combined for use as a single ladder.

section modulus The moment of inertia of
the area of the cross section of a structural mem-
ber divided by the distance from the center of
gravity to the farthest point of the section; a
measure of the flexural strength of the beam.

section mold See joint mold.

sectroid A twisted surface which is between the
groins of a vault.

security alarm system See burglar alarm
system.

security cabinet door-contacts Electrical
contacts mounted on the doors of vaults, secu-
rity file cabinets, etc. When the door is opened,
the contacts separate, thereby activating an
alarm.

864

seepage bed

security glass l.See bullet-resisting glass.

2. See laminated glass.
security glazing Same as security glass.

security grille A metal grating that rolls up

over, or slides across, a window or door to pro-

vide protection against unwanted entry.
security lock See thief-resistant lock.
security screen Heavy screen used as a barrier

against escapes or break-ins; see detention

screen, protection screen.
security window l.A steel industrial-type

window, generally used in stores and warehouses

to provide protection against burglary. 2. A

detention window,
sedge A plant which grows in dense tufts in

marshy places; used to form a ridge on a

thatched roof.
sedile A seat (usually one of three) for the clergy

to the right of an altar, often set in a canopied

niche in the chancel wall.

sedile

sediment The matter which settles to the bot-
tom of water or any other liquid.

sedimentary rock Rock, such as limestone or
sandstone, which is formed from materials
deposited as sediments, in the sea or fresh water,
or on the land. Also see stratified rock.

sedimentation test A laboratory test to deter-
mine the clay content of soil.

sediment trap l.A removable device inside
the body of a drain; used to trap and retain small
solids that pass through the grate. The unwanted
solids that have accumulated are disposed of.
2. In a gas supply system, a trap useful in collect-
ing dirt or other foreign material that may be
entrained in the gas flow, thus protecting the
equipment operating controls.

TO EQUIPMENT

SEDIMENT TRAP

MANUAL GAS VALVE

GAS SUPPLY LINE.
REFER TO PLANS FOR
LOCATION AND SIZES

sediment trap, 2

seedy Descriptive of a paint finish that is not
smooth owing to undispersed pigment particles
or insoluble gel particles in the paint.

seel Old English for canopy.

seepage l.The slow movement of water
through a soil. 2. The quantity of water which
has slowly moved through a porous material,
such as soil.

seepage bed A trench usually exceeding 36 in.
(approx. 1 m) in width containing clean, coarse
aggregate and a system of distribution piping
through which treated sewage may seep into the
surrounding soil.

SEPTIC TANK

seepage bed

865

seepage force

seepage force That force which is transmitted

to the soil grains by seepage.
seepage pit A covered pit with open-jointed

lining through which septic-tank effluent may

seep or leach into the surrounding soil.
seggio A council chamber.
segmental arch A circular arch in which the

intrados is less than a semicircle.

segmental arch

segmental billet A billet, 1 molding formed by
a series of segments of cylinders.

segmental billet

segmental dormer A dormer having a roof
whose cross section is an arc of a circle having a
large radius of curvature.

segmental dormer

segmental member A structural member
made up of individual elements prestressed
together so as to act as a monolithic unit under
service loads.

segmental pediment A pediment whose
upper bounding surface has the shape of an arc
of a circle having a large radius of curvature.

segmental pediment

segmental vault A vault, 1 having the cross
section of a segmental arch.

segment head The head of a door in the shape
of the arc of a circle.

segment saw A large-diameter, specially
designed circular saw, used for cutting veneer
because it makes a very narrow kerf.

segregation The differential concentration of
the components of mixed concrete.

seigneury In medieval England, lands under
the domination of a feudal lord.

seismic load The force produced on a struc-
tural mass owing to its acceleration, induced by
an earthquake.

seismic protection The application of engi-
neering design methods and the installation of
devices that make possible the continuance
of essential services (such as the distribution of
water, gas, electricity, telephone) in buildings
during and immediately after an earthquake.

seismic strengthening Structural reinforce-
ments and modifications made to a building to
improve its resistance to damage from earth-
quakes.

seizing The damaging of one metal surface as a
result of rubbing with another metal surface.

866

self-siphonage

sekos In ancient Greece: 1. A shrine or sanc-
tuary. 2. The cella of a temple. 3. A building
which only the specially privileged might
enter.

Sel In the lumber industry, abbr. for "select."

selected bidder The bidder selected by the
owner for discussions relative to the possible
award of the construction contract.

selected list of bidders Same as invited
bidders.

selected tenderers Same as invited bidders.

selection log See finish and color selection
log.

selective bidding A process of soliciting
competitive bids for the award of a contract for
construction; the owner selects the construc-
tors who are invited to bid to the exclusion
of others, in contrast to the process of open
bidding.

selenite A variety of gypsum in transparent,
foliated, crystalline form; used as decorative
building stone.

selenitic cement, selenitic lime Lime ce-
ment to which 5 to 10% plaster of paris has been
added to increase its hardening properties.

self-ballasted lamp A lamp of the arc-
discharge type (such as a high-pressure mercury
lamp) which incorporates a current-limiting
device.

self-centering lath Expanded-metal rib lath
used on bar joists as formwork for concrete
floors, or for lathing in 2-in. (5-cm) solid plaster
partitions.

self-cleansing velocity In a drain pipe, a flow
velocity that is high enough to initiate scrub-
bing action.

self-climbing tower crane Same as climbing
crane.

self-clinching Said of a nail whose shank
or point clinches automatically when fully
driven.

self-closing device See closing device.

self-closing fire assembly A fire assembly

which is kept in a normally closed position and
is equipped with an approved device to ensure
closing and latching after opening for use.
self-closing fire door A fire door which is
equipped with a closing device.

self-coved Said of sheet vinyl flooring that

extends upward at the perimeter of the floor so

as to form a baseboard.
self-extinguishing Said of a material that

does not continue to burn after the external

source of ignition is removed.

self-faced stone A stone having its natural
face or surface, as a flagstone.

self-finished roofing felt See asphalt pre-
pared roofing felt.

self-furring Said of metal lath or welded wire
fabric having some means of spacing it from a
wall; when plaster, stucco, or concrete is applied
to the fabric, the space makes it possible to key, 8
the applied material to the metal lath or welded
wire fabric.

self- furring nail Same as furring nail.

self-ignition temperature The minimum
initial temperature at which the self-heating
properties of a material lead to its ignition;
dependent on specimen size, heat-loss condi-
tions, and possibly other variables such as mois-
ture content.

self-leveling sealant A sealant which ex-
hibits sufficient flow to level itself by gravity.

self-noise In a sound attenuator in an HVAC
system, the noise which is generated as a result
of the flow of air through the attenuator.

self-reading leveling rod A leveling rod with
graduation marks designed to be read by the
observer at the leveling instrument.

self-sealing fastener A fastener which pro-
vides a seal that is so tight that a sealant material
or mechanical seal is not required.

self-sealing paint A paint which, when ap-
plied over a surface of varying porosity, seals the
surface and yet dries with a uniform color and
sheen.

self-service elevator See automatic elevator.

self-service refrigerator Any type of refriger-
ator found in food stores and other stores where
the customer helps himself; may be of the open
type or may be equipped with sliding or hinged
doors.

self-siphonage The removing of water from a
trap, 1 (thereby breaking the seal) as a result of
siphonage set up by the momentum of discharge
from the fixture to which the trap is connected.

867

self-spacing tile

self-spacing tile Ceramic tile having lugs,
spacers, or protuberances on the sides which
automatically space the tile for grout joints.

self-spreading Said of a nail having a split
shank so that its two or more legs penetrate
material in different directions.

self-stressing Descriptive of expansive-cement
concrete, mortar, or grout in which expansion, if
restrained, induces persistent compressive stresses
in the material.

self-supporting wall, self-sustaining wall
A non-load-bearing wall.

self-tapping screw Same as sheet-metal screw.

self-vulcanizing Said of an adhesive that
undergoes vulcanization without the application
of heat.

seliana window Same as Palladian window.

sellary, sellaria A large sitting-room, drawing
room, or reception room that is furnished with
chairs or benches.

selvage, selvedge 1 . The finished edge of carpet-
ing, a fabric, etc., which prevents raveling. 2. The
unsurfaced strip along a sheet of prepared roll roof-
ing that forms the underportion of the lap. The
plate through which the bolt of a lock projects.

selvage joint In roofing, a lap joint between
mineral-faced cap sheets; mineral surfacing is
omitted along the selvage to provide a better
bond at the joint.

semiarch An arch having only one half of its
sweep developed, as in a flying buttress.

semiautomatic arc welding Arc welding
with equipment which controls only the filler
metal feed; the advance of the welding is manu-
ally controlled.

semiautomatic batcher A batcher equipped
with gates or valves which are opened manually
to allow the material to be weighed separately, but
which are closed automatically when the desig-
nated weight of each material has been reached.

semibasement A basement which is only
partly below ground level.

semibungalow A bungalow or cottage having
an added room or two in the attic area.

semicircular arch A round arch whose intra-
dos is a full semicircle.

semicircular dome A dome in the shape of a
half sphere.

semicircular arcri

semicircular fanlight A fanlight having a
semicircular shape, often located directly above
the main entry of a house.

semicircular vault A barrel or tunnel vault.

semicircular vault

semicircular window 1. A window having a
semicircle at its head. 2. A window having the
shape of a semicircle, often placed above a door
or in a tympanum; also called a D-window.

semi-column Same as half column.

semidetached dwelling A dwelling, one side
wall of which is a party or lot-line wall.

semidetached house One of a pair of houses
joined by a party wall.

semidirect lighting Lighting from luminaires
which distribute 60% to 90% of the emitted
light downward.

semidome A dome equivalent to one-quarter
of a hollow sphere, covering a semicircular area,
such as an apse.

semidome: apse of Suleimanie Mosque, Istanbul 1550 A.D.

868

separate-application adhesive

semi-drying oil An oil having the characteris-
tics of a drying oil, but to a lesser degree.

semielliptical arch Strictly, an arch whose
intrados is half an ellipse; in practice the term
usually denotes a three- or five-centered arch;
also called a basket-handle arch.

semielliptical arch

semielliptical fanlight A window, over the
opening of a door, which has the shape of half an
ellipse; often simply called an elliptical fanlight.

semielliptical fanlight

semiengineering brick A brick whose
strength is intermediate between a building
brick and an engineering brick.

semiflexible joint A joint in reinforced con-
crete in which the reinforcement is arranged so
as to permit some rotation of the joint.

semigloss A level of gloss of paint films; higher
than an eggshell gloss, but lower than a full-gloss
enamel. Also see gloss.

semihydraulic lime A lime intermediate
between a hydraulic lime and a high-calcium
lime.

semi-indirect lighting Lighting from lumi-
naires which distribute 60% to 90% of the emit-
ted light upward.

semi-instantaneous-type water heater

An instantaneous-type water heater having a
sophisticated temperature control system and a
tank of small storage capacity.
seminary A place of education; a school, acad-
emy, college, or university; especially a school
for the education for the priesthood.

semirigid frame A structural framework in
which the columns and beams are connected in
such a way that there is some flexibility at the
joints.

semirubbed finish The surface of a split stone
which has been sand-rubbed to the degree that
prominences have been smoothed flat, but
recessed areas still remain.

semisteel A grade of cast iron of low carbon
content; made by the addition of steel scrap to
pig iron while molten.

semi-vitreous Descriptive of that degree of
vitrification evidenced by a moderate or inter-
mediate water absorption, i.e., a water absorp-
tion of 0.3 to 3.0% except for floor tile and wall
tile, which are considered semi-vitreous when
water absorption is between 3.0 and 7.0%.

sems {sing, and pi.) A machine screw perma-
nently combined with a lock washer which was
inserted before the thread was cut.

sensible heat Heat that changes the tempera-
ture of a material without a change in state, such
as that which would lead to increased moisture
content.

sensible heat factor The ratio of the sensible
heat to the total heat load of an air-conditioned
space.

sensing device See sensor.

sensor, detector, sensing device A device
which senses or detects an abnormal ambient
condition, such as smoke or unusually high tem-
perature; used to initiate an alarm signal, open a
smoke hatch, etc.

SEP On drawings, abbr. for "separate."

separate application The application of com-
ponents of a catalyzed glue or adhesive sepa-
rately to opposite faces of members to be joined;
curing occurs when the faces are joined.

separate-application adhesive An adhesive
consisting of two components, one part being
applied to one adherend and the other part to

869

separate contract

the other adherend; the two are brought
together to form a joint.

separate contract One of several prime con-
tracts on a construction project.

separated aggregate l.A coarse aggregate
which has been divided into components of two
or more sizes. 2. Fine and coarse aggregate con-
sidered separately, as differentiated from a com-
bined aggregate.

separately-coupled pump A pump which is
mechanically coupled to an electric motor
driven by means of a flexible coupling; both
pump and motor are mounted on a structural
baseplate to provide support and to maintain
shaft alignment.

separate sanitary sewer Same as sanitary
sewer.

separate sewer Same as sanitary sewer.

separate system Same as sanitary sewer.

separating wall Same as party wall.

separation The development of layers of paint
of different composition in a can during storage
when the materials are not completely soluble,
miscible, or stable.

separation joint Same as expansion joint, 1.

separator See interceptor.

septic tank A watertight, covered receptacle
designed and constructed to receive the dis-
charge of sewage from a building sewer, separate
solids from the liquid, digest organic matter and
store digested solids through a period of deten-
tion, and allow the clarified liquids to discharge
for final disposal.

MANHOLE COVER

INLET

OUTLET

household septic tank, cross section

septizonium A special type of edifice of great
magnificence, consisting of seven stories of
columns, one above the other, supporting seven
distinct entablatures or zones.

septum l.A low wall or balustrade which
divided the nave of the ancient basilican church
into a middle section (for the clergy) and two
side sections (for the laity). 2. A low wall around
a tomb. 3. The enclosure of the Holy Table
made by the altar rails in a church.

sepulcher l.A tomb. 2. A receptacle for relics,
esp. in a Christian altar. 3. A shallow arched
niche in the chancel to hold the elements of the
Eucharist between their consecration on Maundy
Thursday and the Easter High Mass.

sepulchral Of, or pertaining to, a tomb.

sepulchral effigy

sequence-stressing loss In posttensioning,

the elastic loss in a stressed tendon resulting
from the shortening of the member when addi-
tional tendons are stressed.

seraglio 1 . An enclosed or protected place. 2. A
palace.

serai Same as caravanseray.

serdab l.In ancient Egyptian architecture, a
closed statue chamber. 2. In Mesopotamian
town houses, a cellar under the courtyard, venti-
lated and lighted by skylights, serving as a living
room during the summer months.

serial distribution A group of absorption
trenches (or seepage pits or seepage beds) so
arranged that the total effective absorption area
of one is utilized before liquid flows into the next.

870

service core

FROM
SEPTIC TANK

3^3 ^1=31^ I Bin— J

serial distribution

series circuit A circuit which supplies elec-
tric power to a number of devices connected so
that the same current passes through each
device in completing its path to the source of
supply.

Serlian motif See Palladian motif.
Serlian window Same as Palladian window.

serpent column A type of column used in
Toltec architecture; features a feathered serpent
whose open-fanged head serves as the base and
whose tail rattlers are the roof support. Out-
standing examples at Chichen Itza and Tula, in
Mexico.

serpentine A group of minerals consisting of
hydrous magnesium silicate, or rock largely com-
posed of these minerals; commonly occurs in
greenish shades; used for decorative stone; the
prominent constituent in some commercial
marbles.

serpentine wall A wall that is not straight in
plan but follows a sinuous course. Also called a
crinkle-crankle.

serpentine wall

serrated Notched on the edges, like a saw.
serrated grating A grating which has the top

surfaces of the bearing bars or cross bars (or
both) notched by punching.
SERV On drawings, abbr. for "service."

servants' room In a large home of the past (or
in a dependency of such a home), a common
room in which the servants gathered, ate, and
waited to be summoned. Also called a servants'
hall.

service The conductors and equipment for
delivering electric power from the electricity
supply system to the wiring system of the
premises served.

serviceability The capability of a component,
material, assembly, construction, or building to
perform the function(s) for which it is designed
and used.

service bar A counter on which bartenders
place liquor and other beverages for waiters to
take to their customers.

service box 1. In the electric wiring system for
a building, the box (within the building) at the
point of entry of the service conductors. 2. A
box, usually flush with the pavement, which
provides access to a corporation cock.

service cables l.The service conductors, in

the form of a cable. 2. Those cables and neutral
conductors which are furnished, owned,
installed, and maintained by the utility com-
pany, from the distribution system or overhead
lines to the point of service delivery.

service chute See building service chute.
service clamp Same as saddle fitting.

service conductors In an electric wiring sys-
tem, the supply conductors between the street
mains (or transformer) and the service equip-
ment of the building supplied.

service conduit See service pipe.

service connection An electrical connector
that attaches the utility company's conductors
to the customer's wiring. (See illustration p . 872.)

service core A multistoried space in a tall build-
ing, usually centrally located, that houses essen-
tial building services such as elevators, and/or is
the wiring distribution site for services such as
electricity, telephone, security, fire protection,
communications systems, and plumbing lines.

871

service corridor

Property line

Gull cling wall

Terminating enqlgsi

Service conduit
ond cable

Steel pine sleeve
service connection

service corridor A fully enclosed passageway
other than a passageway required by code for
exiting.

service dead load The calculated dead load;
the calculated dead weight supported by a
member.

service door, service entrance An exterior
door in a building, for the delivery of equipment,
supplies, etc., for the removal of waste, or for the
use of servants.

service drop In the electric wiring system for a
building, the portion of the service conductors
between the last pole of the utility supply and
the junction with the service entrance conduc-
tors of the building supplied.

attaching a service drop to a residential building

service duct A conduit or tube to enclose the
service cables installed by an electrical utility
company.

service elbow Same as service ell.
service elevator A combination passenger
and freight elevator.

service ell, street ell A malleable-iron fitting
for threaded pipe, having a 45° or 90° bend, with
an inside thread on one end and an outside
thread on the other.

service el

service entrance, service entry l.That
part of the customer's installation from the point
of attachment (or termination) of the electric
service lateral to and including the service
equipment on the customer's premises. 2. In a
communications system, the point at which the
network communications lines (e.g., the tele-
phone company lines) enter a building.

service entrance conductors The service
conductors which extend from the point of util-
ity company supply through the wall of a build-
ing to the service switch for the electric wiring
of the building.

ENTRANCE
-(•SWITCH

4 WIRE
SERVICE tf
DROP TO VW

POLE

service entrance conductors

service entrance switch See service equip-
ment, 2.

service equipment 1. Equipment and ma-
chinery for the provision of heat, light, sanitation,
ventilation, fire fighting, transportation, refuse
disposal, etc., which is a permanent part of a build-
ing and subject, therefore, to the code require-
ments governing the installation and use thereof.
2. The necessary electric equipment, located near
the place of entry of the supply conductors in a
building, which constitutes the main control and
means of cutoff for the electrical supply to the
building; usually consists of a switch and fuses or a
circuit breaker and required accessories.

87J

service wiring raceway

service fitting A service ell or service tee hav-
ing a male thread at one end.

service ground A ground connection to a ser-
vice conductor or service equipment or both.

service hatch See hatch.

service head For service entrance conductor, a
type of terminating fitting that prevents water
from entering the interior of the fitting.

weatherproof service head

service integrated ceiling See integrated
ceiling.

service lateral 1 . The underground service
conductors between the street main, including
any risers at a pole or other structure or from
transformers, and the first point of connection
to the service entrance conductors in a terminal
box or meter or other enclosure, inside or out-
side the building wall. 2. The duct from a pull
box, manhole, or vault of a utility company's
underground distribution system to the curb or
property line of a parcel of property.

service lift Same as service elevator.

service live load l.The live load which is
specified by the applicable building code.
2. The nonpermanent load applied under ser-
vice conditions.

service load l.The load which a structure is
expected to support under normal usage; the
nominal load is often taken for this value. 2. See
working load.

service opening Same as intake door.

service period In illuminating engineering,
the number of hours per day for which the day-
light provides a specified level of illumination.

service pipe 1 . The section of pipe which con-
nects the public water or gas main to a termina-
tion point within a building, such as a meter or
trap. 2. In an electric wiring system, the conduit
or pipe that contains underground service con-
ductors and extends from the junction with the
outside supply wires into the premises of the
building served.

service pipe

service point Same as point of service.
service protector Same as power circuit pro-
tector.

service raceway The raceway (such as a rigid
metal conduit or metal tubing) that encloses the
service entrance conductors.

service refrigerator Any commercial refriger-
ator of the reach-in type or refrigerated display
case from which an attendant serves a customer
(as differentiated from a self-service refrigerator).

service riser See riser, 4; riser, 5; and riser, 6.

services See building services.

service sink Same as slop sink.

service stair l.A stairway primarily for ser-
vants, deliverymen, etc. 2. A basement stair.

service switch The electric switch that con-
trols all the energy registered by the meter in the
system (and only that energy).

service tee A malleable-iron fitting for
threaded pipe in the form of a tee having an out-
side thread on one end and an inside thread on
the other and on the branch.

service tee

service termination The point where a util-
ity company's conductors and/or equipment ter-
minate and the customer's wiring begins.

service valve Any valve which isolates an
apparatus from the rest of a piping system.

service wiring raceway See service raceway.

873

servient estate

servient estate See dominant estate.

serving hatch Same as pass-through.

SE Sdg, S.E. Sdg. Abbr. for "square-edge
siding."

set l.The condition reached by a cement paste,
mortar, or concrete when it has lost plasticity to
an arbitrary degree; usually measured in terms of
resistance to penetration or deformation; initial
set refers to first stiffening, final set to attainment
of significant rigidity. 2. The hydration and hard-
ening of a gypsum plaster. 3. To convert a liquid
resin or an adhesive to a hardened state by chem-
ical or physical action such as condensation,
polymerization, oxidation, vulcanization, gela-
tion, hydration, or the evaporation of volatile
constituents. 4. See saw set. 5. In plastering, to
apply a finishing coat. 6. To drive a nail below
the surface of the wood (with the use of a nail
set). 7. The strain remaining after complete
release of the load producing a deformation. 8.
Collectively, the pieces of scenery that make up a
theatrical scene. 9. To coat the back surface of a
tile so that it will adhere to the surface to which
it is applied.

setback The minimum distance between a ref-
erence line (usually a property line) and a build-
ing, or portion thereof, as required by ordinance
or code.

setback buttress A buttress near but not at
the corner of a building.

setback line Same as building line.

set-head nailing Same as blind nailing.

set»in Same as offset, 1.

setoff Same as offset, 1.

set retarder Same as retarder, 2.

setscrew 1. A screw used to fix a collar, knob, or
other detachable part to a shaft or part of a
machine; also called a grub screw. 2. A screw in a
cramp that brings the two sides in close contact.

(WBBBBBBR

ymnttlmtlti'tBltn

iffiffiffi©

setscrews, 1

setting bed The mortar subsurface to which a

terrazzo topping is applied.
setting block A small block of neoprene, lead,

wood, or other suitable material, placed under

the lower edge of a sheet of glass to support it

within a frame.

setting coat See finish coat.

setting-in stick In plumbing, a tool for bend-
ing sheet lead.

setting out The marking of dimensions and
joints on dressed lumber.

setting punch See rivet set.

setting shrinkage A reduction in volume of
concrete prior to the final set of cement; caused
by the settling of the solids and by a decrease in
volume due to the chemical combination of
water with cement.

setting space The distance between the fin-
ished face of a masonry panel (or veneer) and
the backup wall.

setting stuff Obsolete term for finish coat.

setting temperature The temperature to which
a liquid resin or adhesive (or an assembly involv-
ing either) must be heated in order for it to set.

setting time 1 . The length of time required for
gypsum plaster to harden after the addition of
water. 2. The length of time during which a
molded or extruded product must be subjected to
heat and/or pressure to set the resin or adhesive.
3. See initial setting time, final setting time.

setting-up l.The thickening which occurs
when paint stands in an open can. 2. The
increasing viscosity of a paint film as it dries.

settlement l.The downward movement of a
building structure due to consolidation of soil
beneath the foundation. 2. The sinking of solid
particles of aggregate in fresh concrete or mortar
after its placement and before its initial set.

settlement joint A joint between adjacent
parts of a building, structure, or concrete work
that permits the adjoining masses to settle at
slightly different rates.

Settlement phase The time period immedi-
ately following the landing of the English set-
tlers on the American continent; during this
time the colonists provided themselves with
basic shelter and planted crops for the future; see
American Colonial architecture.

87 I

sexpartite vault

settlement shrinkage The volume reduction

in concrete prior to its final set, caused by the

settling of the solids.
settling The sinking of pigments or other solid

matter in paint with a consequent accumulation

on the bottom of the can.
settling basin A basin, in a water conduit,

which allows suspended debris, sand, etc., to

settle.

set tub See laundry tray.

Seven Wonders of the World The seven

most remarkable structures of ancient times:
pyramids at El Gizeh, the Mausoleum at Halicar-
nassus, the Temple of Artemis at Ephesus, Hang-
ing Gardens of Babylon, Colossus at Rhodes,
statue of Zeus at Olympia, and the lighthouse at
Alexandria; of these, only the pyramids at El
Gizeh remain.

severy, civery 1. A baldachin. 2. One bay or
compartment in a vaulted ceiling or structure.

SEW. On drawings, abbr. for sewer.

sewage Any liquid-borne waste, containing
animal or vegetable matter in suspension or
solution; may include liquids containing chemi-
cals in solution; ground, surface, or storm water
may become mixed with it as it is admitted into
or passes through the sewers.

sewage disposal system A system for dispos-
ing of sewage, whether by means of a cesspool,
septic tank, or by mechanical treatment, all of
which is designed to serve a single building or
group of buildings, independently of the public
sewer.

sewage ejector A device for raising sewage by
entraining it in a high-velocity jet of water, air,
or steam.

sewage gas See sewer gas.

sewage pump 1 . A centrifugal pump of special
design, having impellers that can pump large
pieces of solid matter without clogging.
2. A sump pump.

sewage treatment Any artificial process to
which sewage is subjected in order to remove or
alter its objectionable constituents and to render
it less dangerous from the standpoint of public
health.

sewage treatment plant Structures and
appurtenances which receive the discharge of a

sanitary drainage system and which are designed
to bring about a reduction in the organic and
bacterial content of the waste so as to render it
less offensive or dangerous, e.g., a septic tank or
cesspool.

sewer A pipe or conduit for carrying sewage and
other liquid waste.

sewerage The works required to collect, treat,
and dispose of sewage, including the sewer sys-
tem, pumping stations, and treating works.

sewer appurtenances Constructions, devices,
and appliances other than the pipe or conduit,
which are appurtenant to a sewer, such as man-
holes, sewer inlets, etc.

sewer brick A low-absorption, abrasive-resis-
tant brick; used in drainage structures; a blue
brick.

sewer gas A mixture of gases, odors, and vapors
found in a sewer; not of definite chemical com-
position; may include poisonous and com-
bustible gases.

sewer pipe l.Same as sewer. 2. The piping
used in a sewer, e.g., vitrified clay pipe.

sewer system See drainage system and sani-
tary drainage.

sewer tile Impervious tile of circular cross sec-
tion; designed to carry off water or sewage.

sewer trap Same as building trap.

sexfoil A foil, 1 having six points.

sexfoil

sexpartite vault A ribbed vault whose lat-
eral triangles are bisected by an intermediate
transverse rib producing six triangles within a
bay. (See illustration p . 876.)

875

sextry

sexpartite vault

sextry The sacristy of a church.

Sezession The Austrian variant of Art Nou-
veau, so named because its adherents seceded
from the official Academy of Art in Vienna.

SF 6 Sulfur hexafluoride; a gas used in enclosed
electrical circuit breakers because of its arc-
extinguishing properties.

Sftwd. Abbr. for softwood.

sfu Abbr. for supply fixture unit.

SGD Abbr. for "sliding glass door."

Sgraffito A type of decoration executed by cover-
ing a surface, as of plaster or enamel, of one color,
with a thin coat of a similar material of another
color, and then scratching or scoring through the
outer coat to show the color beneath.

SH l.On drawings, abbr. for "sheet." 2. On
drawings, abbr. for "shower." 3. Abbr. for "single-
hung."

shack Same as shanty.

shackle A clevis.

shade 1 . A material hung from, and coiled on, a
ratcheted spring-activated roller; used to pro-
vide privacy, to darken a room, or to reduce the
amount of sunlight striking a window. 2. The
result of the addition of a black dispersion to a
mixture of white and color. 3. See shading and
blending. 4. See shade screen.

shade screen, sun screen A louvered awn-
ing used over windows; the metal blades are
angled to permit good vision downward and

horizontally while preventing the sun, at higher
elevations, from striking the window.

shading and blending Altering the color of a
paint slightly by the addition of black tinting
color to create a decorative effect of graduated
colors when applied to adjacent areas. The lap
areas often are brushed and rolled to achieve a
subtle blending.

shading coefficient The total amount of solar
energy that passes through a glass relative to a l A
inch (3 mm) thick clear glass under the same
design conditions; includes both solar energy
transmitted directly plus any absorbed solar
energy subsequently re-radiated or convected
into a room; lower values indicate better perfor-
mance in reducing summer heat gain and there-
fore air-conditioning loads.

shadow block A concrete masonry unit
whose face is shaped so as to elicit patterns of
light and dark on its surface.

shaft l.The portion of a column, colonette, or
pilaster between the base and the capital. 2. An
enclosed space extending through one or more
stories of a building, connecting vertical open-
ings in successive floors, or floors and the roof.

shaft in Ionic column, section

shafted impost In medieval architecture, an
impost with horizontal moldings, the section of

shafted impost A

876

shaped parapet

the moldings of the arch above the impost being
different from that of the shaft below it.

shafted jamb A jamb with one or more
shafts, engaged or detached, at an angle to the
wall.

shafting In medieval architecture, an arrange-
ment of shafts, wrought in the mass of a pier or
jamb, so that corresponding groupings of archi-
volt moldings may start from their caps at the
impost line.

shaft ring See annulet.

shaft wall The fire-rated wall that isolates an
elevator and/or stairwell core in high-rise con-
struction.

shake A thick wood shingle, usually formed
either by hand-splitting a short log into tapered
radial sections or by sawing; usually attached in
overlapping rows on wood sheathing, 1 as a cov-
ering for a roof or wall.

Shaker architecture Architecture of the
"Shakers," a religious sect of English origin that
founded its first community in America in 1776.
Their structures were built of wood, stone, or
bricks, which they made themselves. Their dis-
tinctive architecture is a combination of un-
adorned simplicity and functionality. Men and
women lived in the same building in separate but
equal facilities; symmetric in plan, with men on
one side and women on the other. In some com-
munities, even the hallways and stairways were
separate. The large meeting rooms for religious
services, usually in a separate building, had no
internal partitions or posts so as to leave an
unimpeded space for the fervent dancing that
formed part of the religious ritual and from which
the sect derived the name "Shaking Quakers" or
"Shakers."

shale Argillaceous sedimentary rock derived
from clays or silts; typically thinly laminated and
weak along planes; may be undesirable as a con-
crete aggregate.

shall When used in a specification, the word
shall is used with reference to the work required
to be done by a contractor or supplier. It denotes
the things the suppliers shall do, documents they
shall supply, features they shall build into the
equipment, or performance levels the equip-
ment shall meet; and indicates a mandatory
specification or requirement.

shallow-bearing foundation A foundation
that is placed directly beneath the lowest part of
a building.

sham door Same as blind door.

shank l.One of the plain spaces between the
channels of a triglyph in a Doric frieze. 2. That
part of a tool which connects the acting part
with the handle. 3. The body of a fastener, such
as a nail or bolt, i.e., the portion between the
head and the point.

I III I IMJ 1 1 IIU PIIM II II II ll II II " 1 1 1 H ■ m 1 1 1 iti irrmrnti it<

mrni

shank, 1

shanty 1. A hut, usually of wood; a small struc-
ture of rough character. 2. A temporary building
on a construction site used for storage or as a
contractor's office.

shape l.Any of a number of metal bars or
beams of uniform section, as an I-beam. 2. To
cut a profile or detail, as a beaded or rounded
edge on a board. 3. To work a material to a
required pattern, as on a shaper.

shaped brick Any brick having a nonstandard
size and/or shape.

shaped gable A gable, 2, each side of which is
multicurved.

shaped parapet Any parapet whose edge does
not follow a straight line; for example, one that
is multicurved, as in a mission parapet.

877

shaped stone

shaped stone Stone that has been carved, cut,
ground, or otherwise processed.

shaped work Curved carpentry or joinery.

shaper l.In woodworking, a machine with a
vertically revolving cutter; used for cutting irreg-
ular outlines, moldings, etc., in wood which is
placed horizontally below the cutter. 2. In met-
alwork, a type of machine tool; a planer in
which the cutting tool moves back and forth
across the work.

shaping machine See shaper.

shark fin In a roofing system, an upward-curled
felt sidelap or endlap.

sharp coat In painting, a coating of white lead
in oil.

sharpening stone Same as whetstone.

sharp flute In a column, one of a series of flutes
that are so close together that they form sharp
arrises.

sharp paint A rapidly drying paint for use as a
seal coat.

sharp sand Coarse sand whose particles are of
angular shape.

shatterproof glass See laminated glass, bullet-
resisting glass.

shave hook A scraping tool used to clean,
shave, or cut lead pipe, prior to soldering.

shay house Same as coach house.

shear 1 . A deformation (e.g., in a beam or flexural
member) in which parallel planes slide relative to
each other so as to remain parallel. 2. To cut a
metal with a pair of moving blades or with one
moving blade and one fixed edge. 3. See shears.

shear center, center of twist, flexural center
Of any cross section of a beam, that point in the
plane of the cross section through which a trans-
verse load must be applied in order that there will
be only bending of the section and no twisting.

shear connector l.A connector (such as a
welded stud, spiral bar, or short length of chan-
nel) which resists horizontal shear between
elements of a composite beam. 2. A timber con-
nector, such as a split-ring connector.

sheared edge An edge of a plate which has
been cut in a shearing machine.

sheared plate l.A plate which has been
sheared from another larger plate. 2. Any plate
the edges of which are sheared.

shear failure, failure by rupture Failure in
which movement caused by shearing stresses in a
soil mass is of sufficient magnitude to destroy or
seriously endanger a structure.

shearhead In the top of the columns of flat-
plate or flat-slab construction, a unit which
transmits loads from the slab to the column.

sheariness In painted surfaces, the variations
in gloss of semigloss or eggshell gloss finishes
resulting from differences in film thickness.

shearing machine A machine for cutting
metal; usually consists of a movable blade which
operates against a fixed cutting edge.

shearing strain See shear strain.

shearing stress See shear stress.

shear joint Same as lap joint.

shear legs A hoisting apparatus consisting
of two or more poles, fastened together near the
top, fitted with a pulley; used to lift heavy weights.

shear lug A steel embedment (such as a bolt,
plate, or welded stud) which is located transverse
to the direction of the shear force and that trans-
mits shear loads introduced into the concrete.

shear modulus See modulus of rigidity.

shear plate 1. One of the reinforcement plates
added to the web of a steel beam to increase the
web capacity to resist shearing loads. 2. A spe-
cial round plate inserted in the face of a timber;
used to develop shear resistance in a wood-to-
metal or wood-to-wood joint; designed to pro-
vide greater load-carrying capacity in shear than
can be achieved by a bolt alone.

shear plates, 2

shear-plate connector A timber connec-
tor used in wood-to-wood or wood-to-steel
assemblies.

shear reinforcement Reinforcement designed
to resist shear stresses or diagonal tension stresses.

shears A cutting tool consisting of two pivoted
blades with beveled edges facing each other.

shear splice A splice between two members
designed to transmit shear between the two
members across the splice.

878

sheer legs

shear strain, shearing strain A deformation
in a structural member (measured in radians)
resulting from the application of a force in a
plane (or line) of a cross section of the member,
perpendicular to the length of the beam.

shear strength The maximum shear stress
which a material or soil is capable of sustaining.

shear stress, shearing stress The force per
unit area of cross section which tends to produce
shear.

shear wall 1. A wall which in its own plane
carries shear, 1 resulting from forces such as
wind, blast, or earthquake. 2. A wall that abuts
another wall at a right angle to it and supports it.

sheath In reinforced concrete, an enclosure
which encases posttensioned tendons to pre-
vent their being bonded during the placement
of concrete.

sheathed cable See nonmetallic sheathed cable.

sheathing, sheeting l.The covering (usually
wood boards, plywood, or wallboards) placed
over exterior studding or rafters of a building;
provides a base for the application of wall or roof
cladding. Also see sheeting. 2. In colonial Amer-
ica, boards on the interior of a house that served
as an interior surface finish.

WALL SHEATHING NAILED
ON DIAGONALLY

diagonal wooden sheathing

sheathing felt A saturated roofing felt.
sheathing paper See building paper.

sheave l.Same as pulley sheave. 2. A grooved
wheel or pulley used to assist in pulling cable;
especially used in underground installations
between manholes.

sheave block An assembly consisting of a pul-
ley wheel, side plates, shaft, and bearings over
which a cable or rope is passed; a pulley block.

she bolt A type of tie and spreader bolt used with
concrete forms; the end fastenings are threaded
into the end of the bolt, thereby eliminating
cones (which are otherwise used) and reducing
the size of the holes left in the concrete surface.

shed A rough structure for shelter, storage, or a
workshop. It may be a separate building or a
lean-to against another structure; often with one
or more open sides.

shed dormer A dormer window whose eave
line is parallel to the eave line of the main roof
instead of being gabled; provides more attic
space than a gabled dormer.

shed dormer

shed roof, pent roof A roof shape having
only one sloping plane.

shed roof

Shed style In American domestic architecture
of the latter half of the 20th century, an architec-
tural style characterized by its roof: usually two or
more shed roofs, steeply sloped in different direc-
tions with no significant overhang; wall cladding
that is vertical, horizontal, or sloped at an angle
parallel to one of the major roof surfaces; a main
doorway intentionally lacking in prominence.

sheepsfoot roller, tamping roller A self-
propelled or towed drum-like roller with project-
ing studs that penetrate the surface of the ground;
used to obtain deep compaction of fill material;
esp. effective for compaction of clay soils. (See
illustration p . 880.)

sheer legs Same as shear legs.

879

sheet

WS--JJ-4

sheepsfoot roller

sheet l.See sheet metal. 2. A flat section of a
thermoplastic resin, 10 mils or greater in thick-
ness, having its length considerably greater than
its width.

sheet asphalt Plant-mixed asphalt cement with
graded sand which passes through a 2.00-mm
(No. 10) sieve and mineral filler; its use ordinar-
ily is confined to surface course construction and
most frequently is laid on a binder course.

sheetflow A storm-water runoff condition
where the flow is shallow and relatively uniform.

sheet glass Ordinary window glass.

sheeting, sheathing 1 . Members of wood, con-
crete, or steel (horizontal or vertical) used to hold
up the face of an excavation. Also see closed
sheeting, open sheeting. 2. See sheathing. 3.
Boards which form the surface of concrete form-
work. 4. Same as sheetpiling. 5. Any material in
the form of sheets. 6. A rock structure in which
there are numerous small closely spaced fractures.

EARTH LEVEL

horizontal sheeting

sheeting clip A metal clip esp. made for fas-
tening various thicknesses of plasterboard,
asbestos-cement board, plywood paneling, etc.

sheeting driver A type of pile driver with a
hammer head designed to fit atop the shaped
steel sections used as sheet piling or timber
trench sheeting.

sheet lath A type of metal lath; fabricated by
punching holes in sheet metal; heavier in gauge
than expanded-metal lath.

sheet lead A cold-rolled sheet of lead, designated
by the weight of 1 sq ft; e.g., a 2-lb sheet (which is
Yn in. thick) weighs 2 lb for an area of 1 sq ft.

sheet metal A flat, rolled metal product, rect-
angular in cross section and form, of thickness
between 0.006 and 0.249 in. (0.015 and 6.32
cm), with sheared, slit, or sawn edges.

sheet-metal door See hollow-metal door.

sheet-metal lath See metal lath.

sheet-metal roofing A thin, rolled metal
product used as roofing; usually flat or corru-
gated; also see corrugated metal and zinc.

sheet-metal screw, tapping screw A
coarse-threaded, tapered screw with a slotted
head for driving with a screwdriver; used for fas-
tening sheet metal and other materials, without
a tapped hole and without a nut.

sheet-metal screws

sheet-metal work Any work with sheet metal,
such as the ducts in an air-conditioning system.

sheet pavement Road surfacing that is free of
joints.

sheet pile One of a number of piles, interlocked
or meshed with similar units, to form a barrier to
retain soil or to keep water out of a foundation.

sheetpiling A barrier or diaphragm formed of
sheet piles; used to prevent the movement of
soil, to stabilize foundations, to construct coffer-
dams, to prevent the percolation of water, etc.

Sheetrock A proprietary name for gypsum
board.

sheet-roofing nail Same as roofing nail.

shelf 1 . A flat surface mounted horizontally,
used to support or store objects. 2. Any project-
ing, flat, near-horizontal surface, such as a ledge
of rock.

shelf-angle An angle iron which is fixed to a
girder to carry the ends of joists.

880

shielded joint

SHEET PILING

sheetpiling

shelf bracket A structural member fastened to
a wall or upright and projecting therefrom to
support a shelf.

shelf cleat, shelf strip A strip of wood used
to support a shelf along one edge.

shelf life The time period during which an
adhesive, coating, sealant, or the like, can be
stored (under specified conditions) and remain
suitable for use.

shelf nog A piece of wood, built into a wall,
which acts as a shelf support.

shelf pin See shelf rest.

shelf rest, shelf pin, shelf support A small
angle bracket held in place by a pin (on the ver-
tical side) which is inserted in one of a number
of holes in a wall or cabinet so that its position
can be adjusted; used in supporting a shelf.

shelf strip See shelf cleat.

shelf support See shelf bracket, shelf rest.

shell 1. A hollow structure in the form of a thin,
curved slab or plate whose thickness is small com-
pared with its other dimensions and with its radii
of curvature. 2. Any framework or exterior struc-
ture which is regarded as not completed or filled
in. 3. An ornament similar in design to a seashell.

shellac A resin extracted and purified from
matter secreted by insects; dissolved in alcohol
or a similar solvent in the manufacture of shellac
varnish.

shell aggregate An aggregate composed of the
crushed shells of oysters, clams, and the like;
generally blended with other fine sands.

shell bit A type of bit, 1 for boring holes in
wood, shaped like a gouge.

shell construction Construction which uses
thin curved concrete slabs.

shell-headed Said of a decoration, generally
concave in shape, that is often similar in appear-
ance to the shell of a sea scallop; often found at
the head of a building component in Spanish
architecture and its derivatives.

shell-headed cupboard A built-in cupboard,
usually in one corner of a room, topped with a
rounded arch containing a decorative element
in the shape of a large seashell; common in the
early 1700s.

shelling See checking.

shell-keep An enclosure or tower, often con-
structed of stones, that is usually circular or
polygonal in shape. Also see keep.

shell lime Lime obtained by burning the shells
of oysters, clams, or mussels; once used in mak-
ing lime mortar, particularly where limestone
was not available for this purpose.

shell ornament Any decoration that is similar
in form to a seashell. Also see coquillage.

shell shake See ring shake.

shell vaulting A vault, 1 whose thickness is
small compared with its other dimensions; usu-
ally fabricated of reinforced concrete.

shelter belt A barrier of trees or very high
shrubs that provides protection against wind;
also see windbreak.

shelving l.A series of shelves, as used in
clothes closets, linen closets, kitchen cabinets,
and other locations; often adjustable. 2. Boards
used for making shelves.

sherardize To coat steel with a thin corrosion-
resistant cladding of zinc.

SHGC Abbr. for solar heat gain coefficient.

shield A metallic layer that surrounds insulated
conductors in a shielded cable; may be the
metallic sheath of the cable or a metallic layer
inside a nonmetallic sheath; especially effective
in providing protection against electrostatic
interference.

shielded conductor An electric conductor
which is enclosed within a metallic sheath.

shielded joint A joint between electrical cables
which has its insulation so enclosed by a con-
ducting shield that every point on the surface of
the insulation is, essentially, at ground potential.

881

shielded metal-arc welding

shielded metal-arc welding Welding which
utilizes the heat produced by an arc between a
covered metal electrode and the work.

shift joint A vertical joint which is above a
solid member of the course below.

shim A thin piece of wood, metal, or stone, usu-
ally tapered, which is inserted under one mem-
ber so as to adjust its height; used in adjusting
the height of one surface so that it is flush with
another.

shim spacer A spacer which positions the face
surface of a pane of glass between the stops and
prevents glass contact with the stops.

shingle A roofing unit of wood, asphaltic mate-
rial, slate, tile, concrete, asbestos cement, or
other material cut to stock lengths, widths, and
thickness; used as an exterior covering on slop-
ing roofs and side walls; applied in an overlap-
ping fashion; usually in one of the following
designs: chisel pattern, coursed pattern, dia-
mond pattern, fishscale pattern, sawtooth pat-
tern. Also see wood shingle and pine shingle.

shingle backer In roofing, an underlayment
applied over the roof sheathing before the shin-
gles are laid.

shingle lap A type of lap joint in which the two
surfaces are tapered; the thinner surface is
lapped over the thicker.

shingle nail A nail for attaching shingles to a
roof; usually galvanized.

shingle nail

shingle ridge finish See Boston hip.

shingle stain A low-viscosity, pigmented, pene-
trating paint for use on wood shingles to provide
color and protection against moisture penetration.

Shingle style An American eclectic style of
domestic architecture especially used from about
1880 to 1900; the Old English style, in using tiles
rather than wood shingles, can be considered a
prototype. Houses in this style are usually rambling
and often asymmetrical in plan, with the exterior
walls covered with unpainted wood shingles that
emphasize the shingled surface and the horizontal
aspects of the house; large porches set within the
main structure or forming part of it; multilevel
eaves with little overhang; occasionally, a tower

«£ S»^

Shingle style

having a conical or bell-shaped roof, usually
topped with a finial; occasionally an eyebrow
dormer; prominent arches at entryways. This style
used in the latter part of the 20th century is some-
times referred to as the "New Shingle style."
shingle tile A flat clay tile used for roofing;
applied in an overlapping pattern.

shinglewood Same as thuya.

shingling hatchet, claw hatchet A carpen-
ter's tool used in shingling a roof, etc.; a small
hatchet combined with a hammer and nail claw.

ship-and-galley tile A special quarry tile hav-
ing an indented pattern on its face to produce an
antislip effect.

shiplap, shiplap boards, shiplap siding

Wood sheathing whose edges are rabbeted to

make an overlapping joint.
shipper A hard-burnt brick that is sound but of

inferior shape.
ship's bottom roof A pitched gable roof

whose slope on each side of a peaked ridge is

slightly bowed, rather than constant.

ship's bottom roof

882

Shore hardness number

ship scaffold Same as float scaffold.
ship spike Same as barge spike.

shivering The splintering that occurs in a fired
glass or ceramic coating owing to critical com-
pressive stresses.

shock hazard According to OSHA: a shock
hazard is considered to exist at an accessible part
in a circuit between the part and ground, or
other accessible parts if the potential is more
than 42.4 volts peak and the current through a
1,500-ohm load is more than 5 milliamperes.

shock load During the placement of concrete,
the load imposed by the impact of material such
as aggregate or concrete as it is dumped or
released.

shock mount Same as vibration isolator.

shoe l.A piece of timber, stone, or metal,
shaped to receive the lower end of any mem-
ber; also called a soleplate. 2. A metal base plate
for an arch or truss which resists lateral thrust. 3.
A base shoe molding. 4. A subrail. 5. A metal
protective device for the point or foot of a pile, 1 .

shoe molding See base shoe, carpet strip.

shoe rail The molding on top of a stair stringer
on which the balusters rest.

shoji A very lightweight sliding partition used
in Japanese architecture; consists of a wooden
lattice covered on one side with translucent
white rice paper. The lattice is most often com-
posed of small rectangles; the lower section is
occasionally filled by a thin wooden panel.

shoji

shoot To straighten the edge of a board with a

plane, 1 .
shooting The placement of shotcrete.
shooting board A device for holding a board

while it is being planed or its edge is being

squared.
shooting plane In carpentry, a light side plane

for squaring or beveling the edge of a board; used

with a shooting board.

shop coat A coat of paint applied to a building
component in the shop before it is sent to a job
site; the finish coat is applied in the field.

shop drawings Drawings, diagrams, illustra-
tions, schedules, performance charts, brochures,
and other data prepared by the contractor or any
subcontractor, manufacturer, supplier, or distrib-
utor, which illustrate how specific portions of
the work, 1 shall be fabricated and/or installed.

shop front See storefront.

shop lumber, factory lumber Lumber which
is graded according to the number of pieces, of
specified size and quality, into which it may be cut.

shop painting The painting of structural steel
or other metals in a shop before final installation
in the construction.

shopping center A concentration of stores,
markets, and service establishments, along with
parking facilities; often in a suburban location.

shopping mall A shopping center enclosed
within a large structure; often two or three sto-
ries high, often designed around a central
atrium; may have numerous stores, as well as
entertainment facilities such as movie theaters,
fast-food outlets, restaurants, and public areas.

shop rivet A rivet driven in the shop.

shopwork Work done in a factory or shop in
contrast to work done on the construction site.

shore A piece of timber to support a wall, usu-
ally set in a diagonal or oblique position, to hold
the wall in place temporarily.

Shore hardness number A numerical scale
for rating the hardness of a material by means of
a device consisting of a small conical hammer
fitted with a diamond point; the hammer strikes
the material under test, and then the height of
rebound (which is a measure of the hardness) is
noted on a graduated scale; the higher the num-
ber, the harder the material.

883

shore up

shore up To hold or support by means of shores.
shoring A number of shores acting collectively.

shoring

shoring layout A pre-erection drawing which
shows the arrangement of equipment for shoring.

short 1. Said of a piece of building material not
up to specified length. 2. A short circuit.

short brace A brace, 3 having a small handle
for working in confined places.

short circuit In an electric circuit, an abnor-
mal connection, having relatively low resis-
tance, between two points of different potential;
causes an abnormally high current flow through
the connection.

short column A column whose load capacity
need not be reduced because of its slenderness.

short-grained See brashy.

short-length 1. A length of stock lumber usu-
ally less than 8 ft (244 cm) long. 2. (Brit.) A
length of sawn hardwood, usually less than 6 ft
(183 cm) long.

short nipple A pipe nipple which is slightly
longer than a close nipple, having a small
unthreaded portion between the pipe threads.

short-oil alkyd An alkyd resin containing less
than 40% oil in the solids.

short-oil varnish A varnish containing little
oil in comparison with the amount of resin
present, less than 15 gal oil per 100 lb (1.5 liters
oil per kg) resin.

short ton Same as ton, 1 ; compare with long ton.

short varnish Same as short-oil varnish.

short working plaster Old plaster (in the plas-
tic state) that will not carry the proper ratio of
aggregate; behaves like a lean, oversanded plaster.

shotblasting A process similar to sandblasting
except that hardened, cast-metal shot is used
instead of sand.

shotcrete Concrete or mortar which is pumped
through a hose and projected at high velocity
onto a surface.

shotcrete gun l.A pneumatic device to
deliver shotcrete under pressure. 2. A pneumatic
device to propel freshly mixed concrete.

shotgun house Built primarily in the rural
southern regions of the United States from the
late 1800s to the early 1900s, a one- or one-and-
a-half-story house (commonly supported on
short piers), one room wide and several rooms
deep, with all rooms and their doors in a straight
line perpendicular to the street; a narrow gable
front with a porch, and often with a similar
porch at the rear.

shot hole A wormhole in wood, usually more
than V\6 in. (1.6 mm) but not more than V& in.
(3.2 mm) in diameter.

shot-sawn finish In stonecutting, the ran-
domly scored surface resulting from chilled steel
shot carried by the gang saw blades. Also see
chat-sawn finish.

shot tower A very high structure, usually
cylindrical and constructed of brick, once used
in making lead shot for muskets. At the top of
the tower, a molten alloy of lead was poured
through a coarse metal screen, forming small
lead globules that solidified; these pellets
became spherical as they dropped, finally
falling into a container of water at the base of
the tower.

should An advisory specification or recommen-
dation.

shoulder l.A projection or break made on a
piece of shaped wood, metal, or stone, where its
width or thickness is suddenly changed. Also
called ear, elbow. 2. The surface bordering a
road, esp. where a vehicle can be parked in
emergency. 3. The angle of a bastion included
between the face and the flank of a fortification.
Also called shoulder angle.

884

show rafter

shoulder angle See shoulder, 3.
shouldered arch A square-headed trefoil arch.

/JOk.

shouldered arch

shouldered corner post Same as musket-
stock post.

shouldered housed joint A type of housed
joint; the full thickness of the edge (or the end)
of one member is inserted in the housing of
another.

shouldered post Same as musket-stock post.
shoulder-headed arch Same as shoulder arch.

shouldering The raising of the edge of a slate
with mortar so that at the lower edge it may
make a closer joint with the slate which it over-
laps and provide a watertight joint.

shoulder nipple l.A nipple, longer than a
close nipple, with a small unthreaded space
between the threads at the end. 2. A nipple
threaded only at its two ends, not over the entire
length.

shoulder nipple

shoulder piece Same as crossette, 2; a bracket.

shoved joint In brickwork, a vertical joint
which is filled with mortar by laying a brick in a
bed of mortar and shoving it toward the last
brick laid.

shovel See power shovel.

shovel dozer Same as dozer shovel.

shower bath, shower An apparatus for spray-
ing water on the body, usually from above.

shower-bath drain The floor drain in a
shower-bath compartment, stall, or enclosure.

shower head In a shower bath, a device (usu-
ally a nozzle having many fine openings) through
which water is sprayed.

*AIH HEAD

shower heads

shower mixer A plumbing valve for mixing
hot and cold water in a shower bath to obtain
the desired temperature.

shower pan In a shower compartment or stall,
a metal pan with sides above the finish floor
level, in which the floor drain is located.

shower pan

shower partition A prefabricated panel, door,

or screen, used in a shower to provide visual

privacy.
shower stall door A glazed door, with or

without a transom, for an individual site-built

shower.
shower tray Same as shower pan.
show rafter A rafter exposed below a cornice;

often ornamental.

885

showroom

showroom A room used for displaying mer-

chandise, goods, and the like.
show-through See telegraphing.

show window Any window used, or designed
for use, for the display of goods or advertising
material, whether it is fully or partly enclosed or
entirely open at the rear; it may have a platform
raised above street level.

shreadhead Same as jerkinhead.

shredding A short, light piece of timber, fixed
as a bearer below the roof, forming a straight line
with the upper side of the rafters.

shrine A receptacle to contain sacred relics; by
extension, a building for that purpose.

shrine chapel A small enclosed structure con-
taining the tomb of a sainted person.

shrinkage 1 . The reduction in dimensions of a
piece of wood during drying; reduction is very
slight along the grain, but a reduction of 5 to 6%
in width is common for dry flat-sawn boards. 2.
The volume decrease of concrete caused by dry-
ing and chemical changes. 3. The proportionate
decrease in dimensions or volume of a material,
usually as a result of a change in temperature.

shrinkage-compensating A characteristic of
grout, mortar, or concrete made with an expansive
cement in which volume increase, if restrained,
induces compressive stresses which are intended
to approximately offset the tendency of drying
shrinkage to induce tensile stresses.

shrinkage crack A crack due to restraint of
shrinkage.

shrinkage cracking Cracking of a concrete
structure or member owing to failure in tension
caused by external or internal restraints as
reduction in moisture content develops, or as
carbonation in the concrete occurs, or both.

shrinkage joint A contraction joint.

shrinkage limit Of a soil, that water content
at which a reduction in water content will not
cause a decrease in the volume of the soil mass,
but an increase in water content will cause an
increase in the volume of soil mass.

shrinkage loss The loss of prestress in con-
crete as a result of the shrinkage of the concrete.

shrinkage reinforcement In reinforced con-
crete, steel reinforcement which is designed to
resist shrinkage stresses.

shrink-mixed concrete A concrete which is
partially mixed in a stationary mixer and then
given its final mix in a truck mixer.

shriving pew Same as confessional.

shroud A place under ground, as a crypt of a
church.

shrub A woody plant with stems branching
from or near the ground and, in general, smaller
than a tree; a bush.

shrunk joint A joint made between the ends
of two pipes (which are cool) by shrinking a
heated piece over the two ends.

shuff Same as chuff.

shute wire In wire cloth, a wire running
directly across the width of the cloth.

shuting Same as eaves gutter.

shutter A movable panel, often one of a pair
used to cover an opening, especially a window
opening; provides privacy and some thermal
insulation when closed; also see battened shut-
ter, boxing shutter, folding shutter.

*™« - 3»rr<a v

:)lid shutters

shutter bar A hinged bar that can be fastened
across the interior side of a pair of shutters. When
the shutters are in the closed position, completely
covering the window, the shutter bar prevents
their being opened, adding a measure of security.

shutter bar

shutter blind An outside adjustable louver
used as a window blind.

886

side-hall plan

shutter box A pocket or recess located along
the interior side of a window to receive shutters
when folded.

shutter butt A small (usually narrow) hinge,
esp. used on shutters and light doors.

shutter dog Same as shutter fastener.

shutter fastener A pivoted device used to
hold a shutter in the open position on the exte-
rior side of a window; also called a shutter catch,
shutter dog, or shutter holdback.

shutter fastener

shutter hinge See H-hinge.
shuttering Same as formwork.

shutter lift A handle fixed to a shutter for con-
venience in opening or closing it.

shutter operator, shutter worker A device
incorporating a crank for opening or closing a
shutter from inside without opening the window.

shutter worker A shutter operator.

shutting post The post at the side of a gate
against which it shuts.

shutting shoe A device of iron or stone with a
shoulder, sunk in the middle of a gateway,
against which the gate is shut and secured.

shutting stile Same as lock stile.

SI The symbol for the International System of
Units.

Siamese connection A wye connection,
installed close to the ground on the exterior

Siamese connection

side of the wall of a building, providing two
inlet connections for fire hoses to the stand-
pipes and fire-protection sprinkler system of
the building.

SIC Abbr. for "Standard Industrial Classification."

sick building A building in which the indoor
air quality is considered to be unacceptable by a
high percentage of its occupants.

sick house A hospital or infirmary.

SIDD See standard inside diameter dimension
ratio.

side aisle Along one or both sides of a church,
an aisle that flanks the main body of the church;
often separated from it by a row of piers or
columns.

side bearer A structural member that runs hor-
izontally along a side wall of a house and sup-
ports a load.

side board, side cut Lumber which has been
sawn from a log in such a way as to exclude the
heartwood.

side chapel A chapel to the side of the choir.

side-construction tile Tile designed to
receive its principal stress at right angles to the
axes of the cells; set in place with the axes of the
cells running horizontally.

side cut l.Same as cheek cut. 2. See side
board.

side-dump loader A type of loader having a
bucket mounted on its front, with a pivot so that
it can be tilted (usually by a hydraulic system);
the bucket can be dumped either to the side or
forward.

side flights See double return stair.

side gable A gable whose face is on one side (or
part of one side) of a house, perpendicular to the
facade.

side girt A girt between corner posts on the
long side of a timber-framed house. See illustra-
tion under timber-framed house.

side grain A surface which is approximately
parallel to the grain.

side gutter A small gutter on a sloped roof,
located at its intersection with a dormer or
chimney or other vertical surface.

side-hall plan, side passage plan A floor
plan of a house having a corridor that runs from
the front to the back of the house along one

887

side-hill barn

exterior wall; all rooms are located on the same
side of the corridor.
side-hill barn A term occasionally used for a

bank barn.
side hinge Same as H-hinge.

Same as bench hook.
window Same as casement

side hook

side-hung

window.

side jamb

side of a door opening.

The vertical member forming the

SIDE JAMB
DOOR STOP

side jamb

side knob screw A setscrew used to fasten a

doorknob to a spindle.
side lap The amount by which one material (or

tile, shingle, etc.) overlaps the adjacent one

along its side or edge.
sidelight A framed area of glass that does not

open, typically composed of a number of small

fixed panes; commonly one of a pair of such
lights, set vertically on each side of a door.

side line The boundaries of a strip of land, such
as a street or right-of-way; does not apply to the
ends of the strip.

side outlet In plumbing, a pipe fitting, 1, either
an ell or a tee, having an outlet at right angles to
the plane of the run.

side-passage plan Same as side-hall plan.

side post One of a pair of truss posts, each set at
the same distance from the middle of the truss,
as a support to the principal rafters and to sus-
pend the tie beams below.

side set The difference in thickness between
the two edges of metal sheet or plate.

side string Same as outer string.

sidesway The lateral movement of a structure
under the action of lateral loads or unsymmetri-
cal vertical loads.

side timber A roof purlin that supports com-
mon rafters.

side vent A vent connecting to the drain pipe
through a fitting at an angle not greater than 45°
to the vertical.

VENT
STACK

SIDE
VENT

C3Ws5tBWf

sidelights with fanlight above do

side vent

sidewalk A paved footwalk at the side of a
street or roadway.

sidewalk door A cellar door which opens
directly on a sidewalk; when closed, it is flush
with the sidewalk.

sidewalk elevator A freight elevator having a
movable platform that operates between a side-
walk outside a building and a different level on a
floor within the building.

sidewalk shed A construction over a public
sidewalk used to protect pedestrians from falling
objects during the erection or repair of a building.

888

signal sash fastener

sidewalk vault A space below a sidewalk
directly adjacent to a building, often covered
with a hatch that can be lifted to allow access to
the basement of the building via steps down;
often used for storage.

sidewall sprinkler In a fire protection system,
a sprinkler providing a one-sided (parabolic)
water distribution outward from a wall.

side yard The yard between the side line of a
building and the adjacent property line, extend-
ing from the front property line to the rear prop-
erty line.

siding A finish covering on the exterior walls of
a building in the form of a series of horizontal
strips or boards; made of such cladding materials
as wood or aluminum. The strips are usually
applied horizontally with an overlap to provide
resistance against the penetration of water. Also
see bevel siding, bungalow siding, clapboard,
colonial siding, drop siding, flush siding, German
siding, lap siding, matched siding, novelty siding,
rabbeted siding, rustic siding, shingles, shiplap
siding, vertical siding, weather slating.

drop siding

siding gauge See clapboard gauge.

siding shingle A shingle of any of a number of
materials such as wood, cement-asbestos, etc.,
used as a protective exterior wall covering over
sheathing.

siege Same as banker.

siel Old English for canopy.

sienna A naturally occurring pigment, chiefly
oxides of iron; yellow-brown when mined.
When calcined, a dark, rich color; then called
burnt sienna.

sieve See screen, 3.

sieve analysis, screen analysis A determi-
nation of the proportions of particles lying
within certain size ranges in a granular material
by separation on sieves of different-size open-
ings.

sieve number A number used to designate the
size of a sieve, usually the approximate number
of sieve cross wires per linear inch.

sight glass A glass tube used to indicate the liq-
uid level in a pipe, tank, or the like.

sighting rod Same as sight rod.

sight line l.In an auditorium, an imaginary,
uninterrupted straight line drawn between the
eye of a spectator and the stage area; if such a
line is impeded by a column, the overhang of a
balcony, etc., vision is restricted. 2. The line of
intersection of a transparent material with an
opaque material.

sight rail One of a series of horizontal rails, usu-
ally boards supported at both ends, which are
used to check the gradient of a pipe in a trench;
the rails are adjusted by sighting a line having
the desired gradient; the rails then establish a
line from which the bottom of the trench can be
measured.

sight rod 1. See leveling rod. 2. See range rod.

sight size In a window opening, the actual size
of the opening that admits light.

sigma A semicircular portico.

sign, signboard l.A display board or
surface used for directions, identification,
instructions, or advertising; usually consists of
lettering, pictures, diagrams, decoration, etc.,
often in combination, on a contrasting back-
ground surface. 2. According to OSHA: a
warning of hazard, temporarily or permanently
affixed or placed, at a location where a hazard
exists.

signage Symbols or words whose function it is
to provide directions, identification, informa-
tion, orientation, warnings, regulations, or
restrictions.

signal light, signal lamp Same as pilot light, 1 .

signal sash fastener A fastening device for a
sash; used to lock a double -hung window which
is beyond reach of the floor; the fastener (which
is operated by a long pole) has a ring on a lever

889

signature stone

which is in the "up" position when the window
is unlocked.
signature stone A stone, found on many
18th- and 19th-century dwellings, carved with
date of completion and the name or initials of
the owner; often embedded in the wall over the
entry door or in a gable.

: ^. m

1 7 ®-7

signature stone

significant architectural feature Any dis-
tinctive aspect of a building's exterior that
defines its architectural character, for example,
the color and texture of the building material or
the style and size of its doors and windows.

significant landscape improvement In a
historic district, any landscape improvement
that is character defining and contributes to the
special aesthetic and historic character of the
designated district.

signinum A waterproof construction material
consisting of terracotta or tiles that have been
broken into minute pieces and then mixed with
mortar; sometimes used as flooring.

signinum opus See opus signinum.

sikhara, sikra Pyramidal or curvilinear tower-
like upper structure of a Hindu temple.

silence chamber Atop a church, a chamber
located between the ringing chamber and the
belfry.

silencer See rubber silencer.

silex 1. Flint or flintstone. 2. By extension, any
kind of hard stone cut into polygonal blocks.

silica, silicon dioxide A white or colorless
substance, nearly insoluble in water and in all
acids except hydrofluoric; extremely hard; fuses
to a colorless amorphous glass.

silica brick A refractory brick made from
quartzite containing about 96% silica, 2% alu-
mina, and 2% lime.

silica gel, synthetic silica A form of silica
which adsorbs moisture readily; used as a drying
agent.

silicate An insoluble metal salt; occurs in con-
crete, cement, brick, glass, clay, and many other
materials.

silicate paint A paint in which sodium silicate
is the binding agent.

silicious aggregate concrete A concrete
produced with aggregates of normal weight that
are primarily composed of silicates of silica.

silicious clay Clay having a high proportion of
silica.

silicon A metallic element, used in pure form in
rectifier units; combined with oxygen, it forms
silicon dioxide.

silicon bronze A copper alloy having silicon
as the main alloying element; zinc, manganese,
aluminum, iron, or nickel may be added; high-
silicon bronze contains 96% copper and 3% sili-
con; low-silicon bronze contains 97.7% copper
and 1.5% silicon.

silicon dioxide See silica.

silicone One of the family of polymeric materi-
als in which the recurring chemical group con-
tains silicon and oxygen atoms as links in the
main chain; derived from silica and methyl chlo-
ride; characterized by resistance to heat and a
low coefficient of thermal expansion.

silicone-carbide paper A very tough, water-
proof sandpaper, shiny black in color; esp. used
in wet sanding and for fine work.

silicone oil A liquid form of silicone; esp. used
for lubrication at high temperatures where
petroleum oil is not effective, also as a water
repellent.

silicone paint Paint that is resistant to very
high temperatures and therefore useful on
smokestacks, heaters, stoves, and electrical insu-
lation; requires heat to cure or set; has a high
resistance to chemical attack.

silicone resin One of a class of silicones con-
taining polymers; has excellent heat resistance,
high water repellency, and chemical resistance;
usually cured by heat.

silicone rubber A synthetic, remarkably sta-
ble, rubber; useful over a very wide temperature
range: -65 to +350°F (-54 to 177°C).

silicon rectifier A solid-state rectifier (i.e., a
device for converting alternating current into
direct current) utilizing silicon wafers; especially

890

silver solder

used to control the current supplying motors,

lighting circuits, etc.
silking Fine parallel lines in a paint film which

follow the direction of flow or drainage of paint

from the work.
sill 1 . A horizontal timber, at the bottom of the

frame of a wood structure, which rests on the

foundation. 2. A doorsill. 3. The horizontal

bottom member of a window frame or other

frame.

sill, 1

sill anchor, plate anchor An anchor bolt

used to fasten a sill to its foundation.
sill bead 1. A draft bead. 2. A glazing bead at a

windowsill.
sill-beam The lowest wood-beam in a sill-wall.
sill block A solid concrete masonry unit used

for sills of openings.
sillboard Same as window sill, 3.
sill cock An exterior water faucet, usually

threaded to provide a connection for a hose;

often located on the side of a building at the

height of a sill.

sill,

sill course In stone masonry, a stringcourse set

at windowsill level; commonly differentiated
from the wall by its greater projection, its finish,
or its thickness.

sill

sill course

sill drip molding See subsill, 1.

sill high 1 . At the height of a sill above the floor.
2. At the height of a sill above ground level.

sill plate 1 . A heavy horizontal timber at the
bottom of the frame of a wood structure; the tim-
ber rests directly on a foundation; same as sill, 1.
2. Same as groundsill.

sill-wall See cill-wall.

silo 1 . A tall, enclosed structure used primarily
to store grain, fodder, or chopped green plants
(silage), or the like; commonly constructed of
wood, masonry, or concrete; usually cylindrical
in shape because this shape provides the tightest
packing of silage and, therefore, results in the
least spoilage. 2. A sunken military structure
used to shelter missiles.

silt, inorganic silt, rock flour A granular
material that is nonplastic or very slightly plastic
and exhibits little or no strength when air-dried;
usually has a grain size between 0.002 mm and
0.05 mm in diameter.

silt grade Said of fine-grained sediment having
particle sizes in the range of that for silt.

silvered-bowl lamp An incandescent fila-
ment lamp that has a hemispherical silvered
reflecting coating opposite the lamp base.

silver grain The grain of quartersawn wood
showing conspicuous shiny flecks or figures; par-
ticularly noticeable in oak, beech, bird's-eye
maple, and sycamore.

silver-lock bond 1. A brickwork pattern simi-
lar to English bond except that each stretcher is
a bull stretcher. 2. Same as rat-trap bond.

silver solder Any high-melting-point solder
containing silver, usually used for soldered joints
where high strength is required.

891

silver white

silver white l.Any white pigment used in
paints. 2. A very pure variety of white lead;
French white, China white.

SIM On drawings, abbr. for "similar."

sima Same as cyma.

simple beam A structural beam having its
ends free and resting only on supports at each
end.

simple cornice A cornice consisting of only a
frieze and molding.

simple vault A vault which has a smooth, con-
tinuous intrados; has no cross arches or ribs.

simplex casement A simple out-swinging
casement window; has no mechanical device for
opening and closing.

simply supported Said of a beam that is
supported so that it is free to rotate at its sup-
ports, and also to expand longitudinally at one
end.

simulated masonry See artificial stone.

sine postico A Classical temple which is
peripteral at the front and sides, but not at the
back.

sine wave A wave form containing only one
frequency; the amplitude of the periodic oscilla-
tion is a sinusoidal function of time. Also see
pure tone.

singing gallery A gallery for singing, usually in
churches of the Italian Renaissance, richly deco-
rated with carving; a rood loft.

single-acting door, single-swing door A
door provided with hinges or pivots which per-
mit it to swing 90° in one direction only.

single-acting pump A reciprocal pump in
which the reciprocating motion of a piston does
work in one direction only.

single-bag compactor, single-bag packer
A semiautomatic refuse compactor in which the
refuse is crushed against a front-opening door
into a specified volume.

single bridging Bridging between adjacent
floor joists; diagonal braces are placed at the
midpoint of the joists.

single-cleat ladder A ladder which consists of
a pair of side rails, usually parallel, connected
together with cleats that are joined to the side
rails at regular intervals; also see double-cleat
ladder.

single contract A contract for construction of
a project under which a single prime contractor
is responsible for all of the work, 1.

single-crib barn See crib barn.

single-cut file A file having serrations in one
direction only.

single-duct system An air-conditioning sys-
tem in which one duct conveys air, at a given
condition, for a number of different spaces.

single-family dwelling A detached house
containing one dwelling unit.

single Flemish bond In brickwork, a bond
utilizing Flemish bond for the facework and
English bond for the body.

single floor A floor consisting only of joists
and flooring; the joists span the distance
between the walls without intermediate support.

single-framed roof A roof framing system
having rafters which are tied together by hori-
zontal boards or the upper floor frame.

single house A house having a long plan that
is only one room wide, with the narrow end of
the house facing the street; the entrance from
the street is up a short flight of stairs to the long
open porch (sometimes called a piazza) that
extends along one side of the house and provides
entry into the individual rooms; for example, see
Charleston house.

single-hub pipe A pipe having a bell, 1 at one
end and a spigot at the other.

single-hub pipe

single-hung window A window having two

sashes, only one of which (usually the lower

one) is movable.
single ladder A portable ladder, consisting of

but one section, which is not self-supporting and

not adjustable in length.
single-lap tile A curved roofing tile which

overlaps only the tile in the course immediately

below it.
single-line diagram Same as one-line diagram.
single-lock welt Same as cross welt.

892

sinking curtain

single measure Said of an object, such as a

door, which is molded on one side only.
single notch Same as half-cut notch.
single-package refrigeration system A

complete factory-made and factory-tested refrig-
eration system in a suitable frame or enclosure
which is fabricated and shipped in one or more
sections and in which no refrigerant-containing
parts are connected in the field.

single-pen cabin A relatively crude one-story
cabin, cottage, hut, or house having only one
room.

single-pile house A house that is only one
room deep; see pile.

single-pitched roof A roof having only a sin-
gle slope on each side of a central ridge; for
example, a gable roof. Compare with shed roof,
which has a single slope but no central ridge.

single-point adjustable suspension scaf-
fold A manually or power-operated platform
designed for light-duty usage, hung by a single
wire rope from an overhead support so arranged
and operated as to permit the raising or lowering
of the platform to the desired working position
by the use of hoisting machines.

single-pole scaffold A scaffold consisting of a
platform resting on putlogs or cross beams, the
outside ends of which are supported on ledgers
secured to a single row of posts or uprights, and the
inner ends of which are supported on or in a wall.

single-pole switch In an electric circuit, a
switch which has one movable contact and one
fixed contact.

single prime contractor A sole contractor
who fulfills the responsibility for construction of
a project.

single-rabbet frame A frame having only one
recess to receive a door.

single-rabbet frame, section

single riveting A single row of rivets.

single-roller catch A type of catch for a door;
a roller, which is mounted on the door, engages a
strike plate on the jamb, thereby holding the
door in a closed position.

single roof A roof supported only by common
rafters; principals, purlins, and roof trusses are
not used.

single-room plan Same as one-room plan.

single- saddle notch A synonym for saddle
notch.

single- sized aggregate An aggregate in
which the largest portion of the particles or frag-
ments are of sizes lying between narrow limits.

single spread The application of an adhesive
to only one of two surfaces to be joined.

single- stack system A type of one-pipe sys-
tem, carrying both soil and waste, that includes
a deep-seal trap.

single-stage curing An autoclave curing
process in which the precast concrete products
remain on metal pallets until stacked for deliv-
ery or yard storage.

single- strength glass Glass which in the US
is approximately Vn in. (2.5 mm) thick; compare
with double-strength glass.

single- suction pump A pump having a spi-
ral-shaped case in which water enters the
impeller from only one side.

single swing frame A frame prepared to
receive one swing door.

single-throw switch A switch, in an electric
circuit, which can be opened or closed by the
operation of a single set of contacts.

single-web girder A built-up flanged girder
whose flanges are connected by a single vertical
web.

sinistral stair A stair that turns to the left in
ascent.

sink A plumbing fixture usually consisting of a
basin with a water supply, connected with a drain.

sinkage See recess.

sink bib A bibcock which supplies a sink with
water.

sinker nail A slender nail having a flat head
(smaller in diameter than that of a common
nail) which has a slight depression in it.

sinking 1. A groove or recess. 2. In wood con-
struction, the removal of some material to per-
mit flush installation of hinges or the like.

sinking curtain A theater curtain which can
be rolled up below the stage floor or lowered
through an opening in the stage floor.

893

sinking in

sinking in In painting, the penetration of the
paint binder into a porous substrate, causing a
low gloss in the finish coat.

sink trap Same as trap, 1.

sinter To form a material from fusible powder by
holding the pressed powder at a temperature just
below its melting point for a period of time; the
particles are fused (sintered) together, but the
mass, as a whole, does not melt.

sintered clay Same as expanded clay.

sintered fuel ash, pulverized fuel ash
Coal ash particles which have been processed so
that they adhere to each other, forming pellets
suitable for lightweight aggregate.

siphonage The withdrawal of liquid, as from a
trap, 1 , resulting from suction caused by liquid
flow.

siphon breaker A backflow preventer.

siphon trap In plumbing, a trap, 1 shaped like
the letter S on its side, in a vertical plane; the
lower bend contains the water seal.

S-iron An exposed retaining plate at each end
of a turnbuckled tie rod between two masonry
walls, to prevent them from spreading.

sisal An organic fiber from the leaves of the sisal
plant; used in making rope and cordage; some-
times mixed with plaster.

sissing See cissing.

site l.An area or plot of ground with defined
limits on which a building, project, park, etc., is
located or proposed to be located. 2. The spe-
cific location of a building or buildings.

site analysis services Those services, pro-
vided by an architect or his consultant, that are
necessary to establish site-related limitations
and requirements for the project; for example,
see geotechnical investigations.

site cast Same as cast-in-place concrete.

site characteristics The distinguishing physi-
cal characteristics of a site, including area,
shape, soil and ground conditions, typography,
and access to the site.

site drainage l.A piping network installed
below grade which conveys rainwater (or other
wastes) to a point of disposal, such as a public
sewer. 2. The water that is drained off.

site-foamed insulation Thermal insulation
which is foamed in place at the building site.

site furnishings Furnishings such as benches,
chairs, tables, kiosks, shelters, playground equip-
ment, and planters for outdoor use.

site improvement Increasing the value or
productivity of land, such as by paving, land-
scaping; also includes the addition of outdoor
lighting, recreational facilities, etc.

site investigation An examination, investiga-
tion, and testing of the subsoil and surface of a site
to obtain complete information necessary for the
design of foundations and the structures on them.

site lighting At a construction site, a system of
temporary lighting used during the construction
process.

site marker See marker.

site plan A plan of a construction site showing the
position and dimensions of the building to be
erected and the dimensions and contours of the lot.

sitework Exterior work on a building under
construction, such as earthwork, landscaping,
paving, and utility services.

Sitka spruce A soft, light, strong, close-
grained wood of the West Coast of the US;
unusually free of knots; esp. used in millwork.

sitting room Same as parlor, 1.

sitzbath A bathtub in which one bathes in a sit-
ting position; used esp. in hospitals or in thera-
peutic treatment.

SI units See International System of Units.

six foil Same as sexfoil.

six-over-six A term descriptive of a double-
hung window having six panes in the upper sash
and six panes in the lower sash; see pane.

six-over-six window

894

skew corbel

size l.Same as sizing. 2. To work a material to
specified dimensions.

sized slate One of many shingle slates of uni-
form or modular size.

size of pipe (or tubing) Unless otherwise
stated, the nominal size by which the pipe (or
tubing) is commercially designated; actual
dimensions are given in applicable specifications.

size stick See scantle.

sizing, size A liquid which is applied over
wood, plaster, or other porous surface to fill the
pores; reduces the absorption of a subsequently
applied adhesive or coating; used to prepare the
surface for finishing or to serve as a base for sub-
sequent coatings.

SJI Abbr. for "Steel Joist Institute."

SK On drawings, abbr. for "sketch."

skaters' cracks In a roofing membrane, curvi-
linear cracks neither related to the direction of
application of the membrane components nor to
the substrate components.

skeeling The sloped ceiling under rafters, as in
a garret, 2.

skeen arch A diminished arch.

skeletal structure A steel framework of

columns and beams that transmits all loads in a
building to the foundation. See skeleton-frame
construction.

skeleton construction A type of construc-
tion, usually for high buildings, in which the
loads and stresses are transmitted to the founda-
tions by a steel framework of beams and
columns; the walls are supported by the frame-
work.

skeleton core The framework within a hol-
low-core door, hidden by the surface panels.

skeleton flashing Same as stepped flashing.

skeleton frame Any framework without its
covering or panels.

skeleton-frame construction A type of
steel construction, usually for buildings of con-
siderable height, in which the loads and stresses
are transmitted to the building foundation by a
framework of steel columns and beams that sup-
port the walls; see steel-frame construction and
skyscraper.

skeleton sheeting, skeleton timbering
Same as open sheeting.

skeleton steps In a stair, steps which have no
risers; the treads are supported on the sides.

skeleton wall Same as panel wall.

skene The Greek term for scaena (Latin).

skene arch A diminished arch.

skenotheke In the skene of an ancient Greek
theater, a storeroom for the properties.

skew Akneeler, 1.

skew arch An arch whose vertical sides are not
at an angle of 90 degrees to its face.

skew arcfi

skewback l.The sloping surface of an abut-
ment which receives the thrust of an arch.
2. The stone, or course of stones, or steel plate,
providing such a sloping surface.

skewback

skew block See gable springer.

skew butt See gable springer.

skew chisel l.A woodworking chisel having
the edge oblique and a bezel on each side. 2. A
chisel used in wood carving which has a bent
shank to allow the edge to reach a sunken surface.

skew corbel A stone built into the bottom of a
gable to form an abutment for a coping, eaves
gutter, or cornice atop a masonry wall. (See illus-
tration p. 896.)

895

skewed

skew t

skewed Having an oblique position, or twisted
to one side.

skewed connection A connection between
two members which are not perpendicular to
each other.

skew fillet A fillet nailed on a roof along the
gable coping to raise the slates there and divert
the water from the joining.

skew flashing Flashing located between a
gable coping and the roof below it.

skew hinge Same as rising hinge.

skew nailing See toe nailing.

skew plane In woodworking a plane in which
the mouth and edge of the iron are obliquely
across the face.

skew putt Same as skew corbel.

skew table A variety of kneeler, cut integrally
with the lowest section of a gable coping; serves as
a lower stop for sloping sections of coping above.

skew vault Same as oblique vault.

skid row, skid road In the United States, an
area in a community characterized by cheap bar-
rooms, saloons, and run-down hotels; usually a
gathering place for derelicts, vagrants, and
down-and-out alcoholics.

skiffling Same as knobbing.

skim coat, skimming coat A thin coat of
plaster; either the finish coat or a leveling coat.

skin A non-load-bearing exterior wall; often
composed of prefabricated panels; also see cur-
tain wall.

skin drying, surface drying The rapid
drying of the surface of a paint film while the

paint between it and the substrate remains
wet.

skin friction The frictional resistance devel-
oped between soil and a structure or between
soil and a pile being driven in it.

skinned bolt A bolt from which the threads
have been stripped.

skinning The growth of a dry film on the sur-
face of paint in a container; caused by oxidation
of the drying oils in the paint binder.

skintled brickwork Brickwork which has
been laid so as to form a wall with an irregular
face.

skintled joint Same as excess joint.

skip l.An area in planed or sanded lumber or
panels which was missed by the machine during
the surfacing operation; also called planing skip,
sanding skip. 2. An uncoated area in a finished
painted surface; also called a holiday.

skirt, skirting l.Same as baseboard. 2. An
apron, 6.

skirting block, base block, plinth block
1. A corner block where a base strip and vertical
enframement meet. 2. A concealed block to
which a baseboard is anchored.

skirting board See baseboard.

skirt»roof A small eavelike projection from the
facade of a house between the first and second
stories, usually encircling the house; provides
some shelter for the windows and doors directly
below it, but is primarily decorative in function.
If it extends only along the front facade, usually
called a visor roof.

skirt-roof

skull In welding, an unmelted residue from a

liquefied filler metal.
skull cracker See wrecking ball.

sky-dome In a theater, a half dome which
curves around and over the stage and which is
painted to represent the sky.

896

slag strip

sky factor The ratio of the illumination on a
horizontal plane at a given point inside a build-
ing due to the light received directly from the
sky, to the illumination due to an unobstructed
hemisphere of sky of uniform luminance equal to
that of the visible sky.

sky light The light received from the sky exclu-
sive of direct light from the sun.

skylight In a roof, an opening which is glazed
with a transparent or translucent material; used
to admit diffused light to the space below. Com-
pare with dome light. Also see hip skylight,
lantern skylight, monitor skylight, pitched sky-
light, sawtooth skylight.

skylight

skyline The outline of buildings against the
background of the sky.

skyscraper A very tall, multistoried building,
usually having curtain walls, 1 so that the exte-
rior walls are non-load-bearing, being supported
independently at each floor by its skeleton-
frame construction; also see steel-frame con-
struction and tripartite scheme.

skyway An enclosed walkway, elevated above
street level, that provides a passageway from one
building to another.

S/L, S/LAP Abbr. for "shiplap."

SL&C Abbr. for "shipper's load and count."

slab l.The upper part of a reinforced concrete
floor, which is carried on beams below. 2. A con-
crete mat poured on subgrade, serving as a floor
rather than as a structural member. 3. A flat
thick slice or plate of material such as stone,
wood, concrete, etc.

slab board A board cut from the side of a log so
that it has bark and sapwood on one side.

slab door Same as flush door.

slab floor A floor of reinforced concrete.

slab form A form for pouring a concrete slab.

slab house A house built of rough-hewn planks.

slab insulation Thermal insulation which is
fabricated in rigid or semirigid form; differs from
block or board-type insulation only in physical
dimensions. The slab designation usually is
applied if the face dimension is much larger than
a block but smaller than a board and if the thick-
ness is greater than that of a board.

slab jacking See mud-jacking.

slab roof A flat, rectangular, structural member
that serves as a roof; often, a reinforced concrete
slab.

slab spacer In a concrete slab, a support and
spacer for the steel reinforcement.

slab strip Same as middle strip.

slack l.Coal of relatively fine size, usually not
exceeding VA in. (6.35 cm) in diameter; often
screenings. 2. Fitting loosely.

slack-rope switch A safety device which
automatically cuts off the electric power from an
elevator motor if the wire ropes (cables) which
hoist the car should become slack.

slack side The side of wood veneer which orig-
inally faced inward in the log.

slag A grayish aggregate left as a residue of blast
furnaces; used as surfacing on built-up roofing
and in manufactured products such as slag
cement and slag wool. Also see blast-furnace
slag.

slag block A masonry unit made of slag
concrete.

slag brick A brick made of crushed blast-fur-
nace slag mixed with lime.

slag cement A finely divided cementitious
material consisting essentially of an intimate
and uniform blend of granulated blast-furnace
slag and hydrated lime.

slag concrete Concrete made with blast-fur-
nace slag as the coarse aggregate; relatively
lightweight.

slag inclusion A nonmetallic solid material
which is trapped within a weld.

slag plaster A plaster having crushed blast-fur-
nace slag as the aggregate.

slag sand Slag which has been crushed to a very
fine aggregate and graded; used in mortar, con-
crete, etc.

slag strip See gravel stop.

897

slag wool

slag 'wool A type of mineral wool made by forc-
ing steam through molten slag; used as thermal
insulation.

slake l.To add water to quicklime, thereby
hydrating it and forming lime putty. 2. To
crumble or disintegrate on exposure to air or
water.

slaked lime A mixture of lime and water, used
as mortar; also see lime mortar.

slaking box A wooden box used to slake
quicklime.

slamming stile Same as lock stile.

slamming strip A strip or inlay along the edge
of the lock stile of a flush door.

slant A sewer pipe which connects a house
sewer to a common sewer.

slant range The line-of-sight distance between

two points not at the same elevation.
slap dash See rock dash.

slasher saw A circular saw attached to a mov-
able arm; used to cut lumber to length.

slash-grained Same as edge-grained.

slash-sawn See plain-sawn.

slat A thin, narrow strip of wood or metal, as in
a window blind.

slate A hard, brittle metamorphic rock consist-
ing mainly of clay minerals, characterized by
good cleavage along parallel planes; used exten-
sively as dimension stone in thin sheets for floor-
ing, roofing, panels (both decorative and
electrical), and chalkboard, and in granular form
as surfacing on composition roofing.

slate-and-a-half slate Slate having the same
length, but VA times the width, of the slate used
elsewhere on a roof.

slate ax A sax.

slate batten, slate lath, tile batten A bat-
ten on which slates or tiles are hung; nailed hor-
izontally across common rafters or counter
battens.

slate black A mineral black obtained by grind-
ing black slate.

slate boarding Close boarding on which roof-
ing slates or tiles are set.

slate cramp A dovetail-shaped heavy slate,
wedged at a joint between two stones to bind
them together.

slate hanging Slate, usually in the form of
shingles, that is hung vertically, or nearly so, on
the face of an exterior wall to prevent the pene-
tration of rainfall.

slate knife Same as sax.

slate lath See slate batten.

slate nail See slating nail.

slate powder A very fine powder obtained by
pulverizing slate; used in paint as a dark-exten-
der pigment.

slate ridge See slate roll.

slate roll, slate ridge A cylindrical rod of
slate; cut with a V-shaped notch on the bottom
side to fit a ridge on a slate roof.

slaters' cement A type of caulking compound
used where a putty-like water-resistant material
is required as a sealant; especially in roofing
applications.

slaters' felt An asphaltic paper used as an
underlayment for slate roofing.

slating 1. The installation of slate shingles on a
roof or wall. 2. Shingles of slate, taken collec-
tively. 3. A roofing of slate.

slating nail, slate nail A nail having a large
flat head and a medium diamond-shaped point,
esp. used for fixing slates.

slating nail

slat window See louver.

sledgehammer, sledge A large hammer hav-
ing two faces; weighs up to 100 lb (45 kg);
grasped with both hands.

sleeper 1 . One of a number of horizontal tim-
bers that are laid on a concrete slab (or on the
ground) and to which the flooring is nailed.
2. Any long horizontal beam, at or near the
ground, which distributes the load from posts or
framing.

sleeper clip A metal fastener which is attached
to a concrete subfloor to fix floor battens in place.

sleeper joist Any joist resting directly on sleep-
ers.

sleeper plate A sleeper, 2.

sleeper 'wall A dwarf wall which carries a
joist supporting a floor; if of brick, it usually is

898

slip-joint conduit

perforated to permit the passage of air for ven-
tilation.

sleepiness A film defect of lowered gloss in a
high-gloss enamel or varnish; develops during
drying.

sleeping porch A porch, or a room lined with
windows, used for sleeping; often located in an
extension to a house, above another porch, or
above a porte cochere.

sleeve See pipe sleeve.

sleeve fence A short, decorative fence, usually
made of light lumber and extending out from a
dwelling.

sleeve piece 1. A pipe sleeve, 1. 2. A thimble.

slenderness In structures, the effective length
of a strut divided by its radius of gyration.

slenderness ratio Of a column, the ratio of its
effective length to its least radius of gyration.

sliced veneer Veneer which is machine-sliced,
from the flat surface of flitch or squared log, in
long, thin, straight slices.

slice-hip roof See Dutch slice-hip roof.

slicing cut A downward cut with a sliding
movement.

slicker A darby.

slick line In delivering concrete by pipeline,
the end section of pipeline which is immersed in
the placed concrete and moved as the work pro-
gresses.

slide pile A pile which is driven into the earth
on a hillside to consolidate the soil to prevent its
sliding down the slope.

slidescape A straight or spiral chute, erected
on the interior or exterior of a building, designed
as a means of emergency egress directly to the
street.

sliding bearing A type of support for a struc-
ture constructed so that one part slides on
another.

sliding bevel See bevel square.

sliding door A door, mounted on track, which
slides in a horizontal direction, usually parallel
to one wall. Also see accordion door, folding
door.

sliding-door lock A lock having a hook-
shaped bolt which, when locked, engages a slot
in a strike plate; esp. used on sliding doors.

sliding fire door A door hung on a sloping
overhead track and held open by a fusible link or
by a magnetic device; closes automatically if the
fusible link is melted by heat buildup or if the
magnetic device is tripped by a smoke-sensing
device.

sliding form See slip form.

sliding sash A window or door which moves
horizontally in grooves or between runners.

sliding window See sliding sash.

slimline lamp An instant-starting fluorescent

lamp having a rugged, single-pin base.
sling See elevator car-frame sling.
sling psychrometer A psychrometer to

which a handle is attached; the apparatus is
whirled in the air until the reading of the wet-
bulb thermometer reaches a constant value.

slip 1 . A strip of wood or other material, esp. one
inserted in a dovetailed groove. 2. A parting slip.
3. A ground, 1. 4. A long seat or narrow pew in
a church. 5. A narrow passage between two
buildings. 6. A thin layer of plaster or grout. 7.
The movement which occurs between concrete
and steel reinforcement in stressed reinforced
concrete; an indication of anchorage break-
down.

slip-critical joint A bolt joint requiring a con-
nection having slip resistance.

slip feather See spline.

slip form, sliding form In concrete construc-
tion, a form designed to move upward slowly
(usually by means of hydraulic jacks or screw
jacks), supported by the hardened concrete of
the wall section which was poured previously.

sliphead window A window in which the
upper part of the sash slides upward through the
head of the window frame.

slip joint l.A vertical joint between an old
masonry wall and a new one; a slot is cut in the
old wall into which brick from the new one is fit-
ted. 2. In plumbing, a connecting joint in which
one pipe slips within another, a seal being
effected by caulking, a gasket, or packing.

slip-joint conduit Metal conduit for electric
wiring, the ends of which are joined to other
pieces of conduit by means of couplings that
slip over the ends; the couplings are not
threaded.

899

slip-joint pliers

slip-joint pliers Pliers having a joint which
can be set in either of two positions, providing a
jaw opening that is either wide or narrow.

slip-joint pliers

slip match The joining of wood sheets, side by
side, so as to provide a decorative pattern, but
not necessarily continuity in grain.

slip mortise See slot mortise.

slip newel A newel which is hollowed out at
the bottom to fit over a short vertical post, or
cut away at one side to fit over the end of a
partition.

slip-on flange A solid, circular pipe flange
which is slipped over the end of a pipe and
welded in place.

slippage In built-up roofing, the lateral move-
ment between adjacent plies; esp. occurs on
sloping roofs.

slipper 1. On a running mold, a metal shoe that
slides on the running rule. 2. Same as plinth.

slip pew A small enclosed pew having a single
seat.

slip piece A strip of wood attached to a sliding
member to serve as a wearing surface.

slip-resistant tile Ceramic tile having greater
nonslip characteristics than ordinary tile
because of an abrasive admixture, abrasive parti-
cles in the surface, or grooves or patterns in the
surface.

slip sheet A dry sheet of light roofing paper.

slip sill A sill no longer than the distance
between the jambs of the opening, so that it can
be set into the aperture after the walls are built.

slipstage A wagon stage on tracks.

slip stone See gouge slip.

slip tongue See spline.

slip-tongue joint A spline joint.

slit ventilator One of a number of long vertical
slots in the masonry walls of a German barn to
supply fresh air to the barn; occasionally called a
slit window or a loophole.

slogging chisel A heavy chisel used to cut off
bolt heads.

slop Same as sludge.

slope l.See grade. 2. See pitch, 3. 3. See
incline. 4. See grain slope.

slope correction Same as grade correction.

sloped footing A footing which has sloping
top or side faces.

sloped offset chimney Same as stepped-back
chimney.

slope map A map indicating the topography of
an area along with an analysis of topographic
features as they have influenced and may con-
tinue to influence land development.

slope ratio Relation of horizontal distance to
vertical rise or fall; e.g., 2 ft horizontal to 1 ft
vertical is designated 2 to 1 or 2:1.

slope stake A stake, driven in the ground,
indicating the line where a cut or fill meets the
original grade.

sloping grain l.Same as diagonal grain.
2. Also see grain slope.

sloping shore A flying shore that is at an angle
to the horizontal, rather than being horizontal.

slop-molding, soft-mud process A method
of manufacturing stock brick and multicolored
brick; makes use of clay having a high water con-
tent.

slop sink A deep sink, usually set low, esp. used
by janitors for emptying pails of dirty water.

slop sink

slot diffuser See linear diffuser.

slot mortise, open mortise, slip mortise

A mortise which is open on three sides of the
member in which it is formed.

900

slurry

slot mortise

slot outlet A long, narrow air outlet, with lon-
gitudinal vanes for directing the supply of air,
having an aspect ratio greater than 10:1; may be
located in the ceiling, sidewalls, floor, or sill.

slot weld A weld between two members, one
containing an elongated hole through which the
other member is exposed; the hole is completely
or partially filled with weld metal, thereby join-
ing the two members; one end of the hole may
be open.

sloughing When freshly gunned shotcrete is
applied to a vertical surface, the slipping down of
the material from the place where it was applied,
usually because of the excessive use of mixing
water.

slow burning A misleading term implying a
general property of a material or product when it
is exposed to a fire of any size or severity; mean-
ingful only when identified with a particular
test, usually applying only to very small flames
for a short time period.

slow-burning construction Descriptive of
buildings of timber construction designed to be
fire-retardant; see textile mill.

slow-burning insulation Insulation which
burns or chars without a flame.

slow-curing asphalt Liquid asphalt composed
of asphalt cement and oils of low volatility.

slow-evaporating solvent A solvent which
evaporates slowly because of its high boiling
point; used in paint to maintain the paint film in
a fluid state for a longer time than usual, thereby
improving the flow properties of the paint.

slow-grown See narrow-ringed.

sloyd knife A woodworker's knife having a
fixed, single blade; used in wood carving, slicing,
and trimming.

sludge 1. Refuse from various operations, as the
waste material produced in the wet grinding of
terrazzo. 2. In a paint spray booth whose walls
are washed continuously with water, the paint
which accumulates in the water reservoir, some-
times reworked to make another paint. 3. The

accumulated, settled solids which are deposited
from sewage and contain more or less water to
form a semiliquid mass.

sludge clear space The distance between the
top of the sludge, 3 and the bottom of an outlet
device in a tank containing sewage.

sluing arch A splayed arch.

slum An area within a city characterized by
deteriorated buildings, unsanitary conditions,
and high population densities.

slump A measure of consistency of freshly
mixed concrete, mortar, or stucco; equal to the
decrease in height, measured to the nearest X in.
(6 mm) of the molded mass immediately after its
removal from a slump cone.

slump block A concrete masonry unit which
settles during curing so that the base is slightly
enlarged; used in masonry wall construction.

slump cone A mold in the form of a truncated
cone with a base diameter of 8 in. (20 cm), top
diameter 4 in. (10 cm), and height 12 in. (30
cm); used to fabricate a specimen of freshly
mixed concrete for the slump test; a cone 6 in.
(15 cm) high is used for tests of freshly mixed
mortar and stucco.

slump mold Same as slump cone.

slump test A procedure using a slump cone for
measuring the slump of concrete.

slump test

slurry 1 . A mixture of water and any finely
divided insoluble material such as clay or port-
land cement and water. 2. See mud.

901

slurry coat

slurry coat A coating on the back of a ceramic
tile unit to ensure that it adheres firmly to its
backing.

slurry explosive Same as water-gel explosive.

slushed joint A vertical joint filled after a
masonry unit is laid by slushing mortar into the
joint with the edge of a trowel.

slush grouting The distribution of portland
cement slurry, with or without fine aggregate,
over a rock or concrete surface that is to be cov-
ered subsequently with concrete, usually by
brooming it in place to fill surface voids and
fissures.

slype A narrow passage as between two build-
ings; a slip, 5.

SM l.Abbr. for "standard matched." 2.Abbr.
for "surface measure."

small calorie See calorie.

smalt A deep blue pigment or coloring material;
a vitreous substance made of cobalt, potash, and
calcined quartz, fused and reduced to a powder.

smalto Colored glass or other pieces of vitreous
material, esp. in minute regular squares, used in
mosaic work.

smalto

smart building Same as intelligent building.

smashing point The time beyond which it is
not economical to burn old lamps because of
their increasing inefficiency; based on an evalua-
tion of the cost of operating the lighting system.

smell test See scent test.

smoke 1. An air suspension of particles, usually
but not necessarily solid. 2. Carbon or soot par-
ticles less than 0.1 micron in size which result
from the incomplete combustion of carbona-
ceous materials such as coal and oil.

smoke and fire vent A vent cover, installed
on a roof, which opens automatically when the
heat exceeds 160°F (71.4°C), thereby releasing
the door and venting the fire.

smoke barrier Any type of continuous barrier
of noncombustible construction, designed and
constructed to restrict the spread of smoke in a
building.

smoke chamber In a fireplace, the space
directly above the chimney throat, where the
smoke gathers before passing into the flue.

smoke control zone A space within a build-
ing enclosed by smoke barriers.

smoke curtain A barrier that restricts the
spread of smoke.

smoke damper A damper, 1 arranged to seal
off air flow automatically through part of an air
duct system, so as to restrict passage of smoke.

smoke density The ratio of (a) the smoke
emitted by a burning material to (b) the smoke
emitted by a standard material.

smoke detector A device for sensing the pres-
ence of smoke in a building — usually by means
of a photoelectric detector, ionization detector,
ultraviolet flame detector, or a heat detector.

smoke-developed rating A relative numeri-
cal classification of a building material as deter-
mined by an ASTM test of its surface burning
characteristics.

smoke door In the roof of a theater, above the
gridiron, a door which opens automatically in
case of fire or when a release line is cut; confines
the smoke to the backstage area.

smoke-dried lumber Lumber which has been
seasoned by a process in which boards are
exposed to the smoke and heat of a fire main-
tained beneath the stacks.

smoke exhaust system A mechanical or

gravity system intended to convey smoke from
one portion of a building to the outdoors; usually
includes a purging-and-venting system, as well
as exhaust fans.
smoke hatch Same as smoke door.

smoke hole In many types of primitive
dwellings, a hole in the roof that permits smoke
and fumes to escape from an open firepit below,
also provides a source of light and ventilation in
the dwelling.

902

smooth-surfaced roofing

smoke hood A hood, 2.

smokehouse An enclosed outbuilding in
which meat or fish is cured with smoke to pre-
serve it; usually has a vent, a single door, and no
windows, walls typically constructed of boards,
brick, logs, or stone, often with a gabled or pyra-
midal roof.

smoke load That fraction of the fuel load
which has the potential of producing smoke.

smoke outlet See smoke exhaust system.

smoke pipe, smoke vent 1. A pipe or duct
which carries smoke outside a building or to
a flue. 2. Same as breeching, 1.

FURNACE

CHIMNEY-

CHECK SMOKE
DRAFT PIPE

CLEANOUT
CLEANOUT.

smoke pipe

smoke pocket A vertical metal slot, on both
sides of the proscenium arch, in which the edges
of the asbestos curtain move.

smokeproof enclosure A fully-enclosed,
ventilated vestibule that is sufficiently above
atmospheric pressure so as to provide a smoke-
less safe passage in the event of a fire.

smokeproof tower A stairwell which pro-
vides with direct access to outdoor air at each
floor level and which meets the requirements of
the applicable code.

smoke rocket A device which gives off dense
smoke; used in a smoke test of sections of piping.

smoke shaft See smoke pipe.

smoke shelf A concave shelf on the back wall
of a smoke chamber, just above the throat, to

redirect downdrafts into updrafts on the front
wall of a smoke chamber.

smokestack A chimney.

smokestop A partition to retard the passage of
smoke; any opening in such partition is pro-
tected by a door equipped with a self-closing
device.

smoke stop door A door or pair of doors
placed in a corridor to restrict the spread of
smoke and to retard the spread of fire by reduc-
ing the draft.

smoke test A test in which nontoxic, visible
smoke is introduced in an air-distribution sys-
tem, ductwork, piping, etc., to indicate the
routes taken by air currents and/or to detect
leaks.

smoke tower window In a high-rise build-
ing, an interior window, used between a stairwell
and a smoke tower or smoke vent, which pro-
vides an automatic means for venting heat and
smoke in the event of fire; an automatic mecha-
nism causes the window to open quickly if sen-
sors detect the presence of smoke or a high
temperature rise.

smoke vent l.See smoke pipe. 2. See smoke
and fire vent.

smoldering The combustion of solid materials
without the accompaniment of flame.

smooth ashlar A rectangular stone block hav-
ing smooth faces, ready for laying.

smooth finish See smooth machine finish.

smooth-finish tile Ceramic tile whose sur-
faces are not altered or marked in manufacture
but are left flat or level as formed by the die.

smoothing plane A small fine plane used for
finishing.

smooth machine finish, machine finish,
smooth finish, smooth planer finish A
finish on a stone surface, produced by a planer
with a smooth-edged cutting tool that shaves
without plucking; tool marks, if evident, are
removed by a carborundum wheel, by hand
scraping, etc.

smooth planer finish See smooth machine
finish.

smooth-surfaced roofing A built-up roof-
ing membrane which is surfaced with (a) hot
asphalt applied with a mop; or (b) cold asphalt

903

SMS

emulsion or a cutback roof coating; or (c) an
inorganic top felt. It does not have a mineral
surface aggregate.

SMS Abbr. for sheet-metal screw.

smudge l.A mark or smear on a surface, as
from a hand or object rubbing dirt on a paint
film. 2. The scrapings and cleanings of paint
pots, mixed together and used as a primer. 3. In
plumbing, a mixture of glue sizing and lamp-
black; painted on a lead surface to prevent sol-
der from adhering.

snack bar An eating facility where quick, light
meals, refreshments, or snacks are served, usually
at a counter.

snake 1. A long tempered-steel, resilient wire,
usually having a rectangular cross section, used
by electricians in pulling wires through con-
duit or through an inaccessible space; the
snake is threaded through first, followed by the
wire. 2. A tool used by plumbers to unblock a
pipe or sanitary fitting; usually a highly flexible
metal wire, given a rotary motion by a crank at
one end.

snake fence Same as zigzag fence. Also see
serpentine wall.

snakestone A kind of hone slate or whetstone;
used for polishing scagliola or the like.

snakewood Same as letterwood.

snap See rivet set.

snap head Same as buttonhead.

snap header A brick header that has been cut
in two, at the middle of the long edge.

snapped work Masonry laid with consider-
able use of snap headers rather than full
headers.

snapping line A cord used to mark a straight
line in laying out masonry, carpentry work, etc.
Chalk is applied to the cord along its entire
length, and the cord is held taut between two
points on the surface to be marked; when the
cord is raised and snapped, it leaves a chalk line
on the surface.

snap switch A manually operated switch used
in interior electric wiring; usually used for the
control of lighting or small motors.

snap switch with cover removed

snatch block A pulley block that can be
opened on the side to receive the bight of a rope.

S»N curve Same as stress-number curve.

sneck 1. In snecked rubble, one of the smaller
stones used to fill interstices and to even out
courses in a rubble wall. 2. The lever in a lift
latch.

snecked rubble, snecked masonry Ma-
sonry laid up with rough irregular stones, fitted
so as to produce a strong bond.

snecking Same as rubblework.

snipe's-bill A carpenter's plane with a sharp
arris used to form the quirks, 1 in moldings.

snips Same as tin snips.

snow board, snow cradling A continuous
narrow board or strip, secured at the foot of a
roof slope, which serves as a snow guard.

snow fence Same as snow guard.

snow guard Any device intended to prevent
snow from sliding off a sloping roof.

snapping line

snow guards (two types)

904

sod house

snow hook A device in the form of a loop of
wire or a metal hook which is fastened to a slop-
ing roof and serves as a snow guard.

snow house See igloo.

snow load The live load due to the weight of
snow on a roof; included in design calculations.

snubber 1 . A component of a vibration isolator
that limits the displacement of the isolator in
either the vertical or horizontal direction. 2. On
a very large expulsion-type fuse, a silencer that
reduces the loud noise produced in clearing
heavy electrical faults.

Equipment

/ Standard

vibration isolator

snubber, 1

soakaway, soakpit A pit excavated in the
earth's surface which receives excess surface
water, allowing it to drain away slowly.

soaker On a slate or tile roof, a piece of metal
sheeting used to make a weathertight joint at
the intersection between the roof and a vertical
wall penetrating the roof or at a hip or valley.

soaking period In steam curing of concrete
products, the time after which the steam supply
to the kiln or autoclave is shut off and the prod-
ucts are left to soak in the residual heat and
moisture of the curing kiln.

soap A brick or tile of normal face dimensions,
having a nominal 2-in. (5-cm) thickness.

soapstone Massive soft rock that contains a
high proportion of talc; used as dimension stone
for laboratory sinks, bench tops, carved orna-
ments, and electrical panels. Also see steatite.

Society of Architectural Historians A

society dedicated to the encouragement of schol-
arly research in the field of architectural history;
founded in 1940 as the American Society of
Architectural Historians, and called the Society
of Architectural Historians since 1947. Address:
1365 North Astor Street, Chicago, IL 60610.

socket l.Same as coupling. 2. British term for

bell, 2. 3. A receptacle outlet.
socket chisel See mortise chisel.
socket fuse Same as plug fuse.

socketing In timber construction, the connec-
tion of one member with another by fitting it
into a mating cavity in the second one.

socket outlet 1 . British term for receptacle
outlet. 2. See outlet.

socket pipe A cast-iron pipe which is provided
with a socket at one end and a spigot at the
other end.

socket plug A pipe fitting with an outside
thread and a head having a recess into which a
wrench is inserted for turning it.

socket tile A sewerpipe of vitrified clay having
bell-and-spigot joints between sections of pipe.

socket wrench A box wrench having a
recessed socket at the end of its shank which fits
over a nut.

socle A low, plain base course for a pedestal,
column, or wall; a plain plinth.

sod The upper layer of soil covered by grass and
containing the grass roots.

soda-acid fire extinguisher One that dis-
charges water under the pressure of carbon diox-
ide gas produced by mixing acid and soda when
the extinguisher is activated; the water may con-
tain unreacted acid or soda.

soda fountain A system for dispensing soda
water, usually equipped with a self-contained or
remote refrigeration system with compartments
for ice cream; may include a built-in sink and
carbonator; esp. used at counters in drugstores
and in restaurants.

soda-lime glass Glass manufactured by fusing
sand with sodium carbonate or sodium sulfate
and lime; used for window glass.

sod house, soddie A dwelling having thick
walls of blocks cut from an upper layer of grass-
land (i.e., sod). Houses of this type were con-
structed quickly by early settlers in the Great
Plains of the United States in areas where tim-
ber and stone were scarce, suitable clay was not
available for making bricks in quantity, but
good-quality sod was readily obtainable. Often,
constructed partially underground, or built into
the side of a hill to provide improved thermal

905

sodium light

insulation. The walls were usually plastered with
clay to promote cleanliness and dryness within
the structure, and to reduce or prevent insect
infestation. Also see Plains cottage.

sodium light Monochromatic yellow-orange
light from a low-pressure sodium-vapor lamp.
Also see high-pressure sodium lamp.

sodium-vapor lamp An electric-discharge
lamp in which light is produced by electric cur-
rent flowing between electrodes in an envelope
containing sodium vapor.

sod roof A roof composed of a thick layer of
grassland containing roots; frequently pitched
or barrel-shaped and supported by logs; usually
prone to problem of water leakage. In sod
houses of better quality, the sod roofs were cov-
ered with shingles (which were then covered
with additional sod to prevent the shingles from
being blown away). In upscale modern sod
houses, an impermeable plastic sheet is set
beneath the sod roof to reduce or eliminate
water leakage.

soffit The exposed undersurface of any overhead
component of a building, such as an arch, bal-
cony, beam, cornice, lintel, or vault.

soffit of an arch and of a lintel, S

soffit block A concrete masonry unit used in
concrete floor or roof construction where the
soffit of a concrete beam is concealed by a face
shell of the unit.

soffit block

soffit board A plancier piece.

soffit bracket A bracket for mounting an
exposed overhead door closer to the underside of
a doorframe head or transom bar; used for out-
swinging doors only.

soft brick Same as salmon brick.

soft-burnt Descriptive of a clay product which
has been fired at a low temperature, resulting in
relatively high water absorption and low com-
pressive strength.

softener A flat brush of hog bristle; used to
blend or soften markings in a paint coating.

softening point An index of a bitumen's fluid-
ity; the temperature at which a bitumen (used in
roofing or road construction) softens or melts.

soft glass A glass, usually of soda-lime composi-
tion, having a low softening point and a high
coefficient of thermal expansion which renders
it susceptible to thermal shock, e.g., window
glass.

soft light Light which produces soft, poorly
defined shadows.

soft-mud brick Brick produced by molding
relatively wet clay (20 to 30% moisture), often
by hand; if the inside of the mold is sanded to
prevent sticking of clay, the product is sand-
struck brick; if the mold is wetted to prevent
sticking, the product is water-struck brick.

soft-mud process See slop-molding.

soft particle In an aggregate, a particle which
possesses less than a specified degree of hardness
or strength.

soft solder A low-melting-point solder.

soft water Water, free of magnesium or calcium
salts, in which soap readily dissolves, forming a
lather without being precipitated.

softwood Wood from the evergreens; usually
relatively soft and easy to cut and work,
although some woods so classified in the US are
harder than others classified as hardwood.

soil 1 . Sediments or other unconsolidated accu-
mulations of solid particles produced by the
physical and chemical disintegration of rocks;
may or may not contain organic matter. 2. Same
as sewage.

soil absorption field Same as absorption field.

soil absorption system Any system that uti-
lizes the soil for subsequent absorption of the

906

soil survey

treated sewage; such as an absorption trench,

seepage bed, or seepage pit.
soil analysis See mechanical analysis.
soil auger See auger, 2.

soil binder Soil which just passes through a
420-|i (No. 40 US Standard) sieve.

soil boring Drilling into the soil to explore the
subsurface and to obtain earth samples.

soil branch A branch line of a soil pipe.

soil-cement A mixture of mineral soil, cement,
and water used to make a hard surface for side-
walks, pool linings, and reservoirs, or as a base
course for roads.

soil class A numerical classification of soil, 1 by
texture, which is used by the US Department
of Agriculture: (1) gravel, (2) sand, (3) clay,
(4) loam, (5) loam with some sand, (6) silt-
loam, and (7) clay-loam.

soil classification test A test in which soils are
classified in broad groups having similar mechan-
ical properties and strength characteristics.

soil compaction See compaction, 2.

soil cover Same as ground cover, 2.

soil creep The very slow movement of soil
down a slope, under the influence of gravity.

soil depth The depth of soil to which the roots
of a plant can readily penetrate in order to reach
water and nutrients.

soil drain A horizontal soil pipe.

soil engineering The application of the prin-
ciples of soil mechanics in the investigation,
evaluation, and design of civil works involving
the use of earth materials and the inspection or
testing of the construction thereof.

soil fill Same as fill or backfill.

soil horizon A layer of soil, approximately hor-
izontal, which differs in structure and composi-
tion from the adjacent layers.

soil mechanics The application of the laws
and principles of mechanics and hydraulics to
engineering problems dealing with soil as an
engineering material.

soil pipe, soil line A pipe which conveys the
discharge of water closets or fixtures having
similar functions, with or without the dis-
charges from other fixtures. Also see cast-iron
soil pipe.

soil pipe bend Same as sanitary bend.

soil plug The "plug" that is formed when an
open-ended pipe pile is driven into the ground.

soil pressure Same as contact pressure.

soil profile The vertical section of a soil, 1 ,
showing the nature and sequence of the various
layers, as developed by deposition or weathering,
or both.

soil sample A small specimen of soil usually
taken from a boring.

soil stabilization The application of a chemi-
cal or mechanical treatment of a mass of soil to
increase or maintain its stability or improve its
engineering properties.

soil stabilizer l.A machine, used in site
preparation, that mixes in place earth and
added stabilizing materials (such as cement or
lime) to obtain higher soil-bearing capacity;
rapidly rotating tines pick up and blend the soil
with the stabilizing agent. 2. A chemical used
to improve the physical properties of soil, 1 or
to maintain or increase the stability of a mass
of soil.

soil stack A vertical soil pipe carrying the
discharge from toilet fixtures.

— STACK VENT

WATER CLOSET

SOIL STACK

soil stack

soil structure The arrangement and state of
aggregation of soil particles in a soil mass.

soil subsidence The consolidation of soil
other than by externally applied pressure.

soil survey At a construction site, a detailed
investigation of the soil, accompanied by a writ-
ten report, usually including information con-
cerning the type of soil, its thickness and
strength, and the location of bedrock.

907

soil suspension

soil suspension A highly diffused mixture of
soil and water.

soil texture 1. In a mass of soil, the relative
proportion of clay particles to the sand and silt
particles. 2. The particle-size distribution of a
mass of soil.

soil vent Same as stack vent, 1.

solar l.Said of radiant flux that has the sun as
its source. 2. A room or apartment on an upper
floor, as in an early English dwelling house.

solar collector A device designed to absorb
radiation from the sun and transfer this energy
to a fluid which passes through the collector.

solar collector efficiency The ratio of the
energy produced by a solar collector to the
energy that is incident on it.

solar constant The average rate at which radi-
ant energy is received by the earth from the sun;
equal to 430 Btu per hr per sq ft (1.94 cal per
min per sq cm); a constant employed in calcu-
lating air-cooling loads due to the effects of solar
radiation on buildings.

solar control glass See coated glass and tinted
glass.

solar cooling system A system which con-
verts solar energy into other forms of energy,
then uses it for cooling.

solar degradation The deterioration in the
properties of a material or component caused by
exposure to solar energy.

solar energy system A building subsystem
used to convert solar energy into thermal energy
for heating and/or cooling a building or heating
water for use within the building; may be of the
hybrid-, open-, passive-, or thermosiphon-types.

solar fraction The ratio of the amount of input
energy contributed by a solar energy system to
the total input energy required for a specific
application.

solar glass Glass that has been tinted to reduce
the transmission of sunlight through it; same as
tinted glass. Also see bronze glass.

solar heat Heat supplied by radiation from
the sun.

solar heat gain coefficient The fraction of
normally incident solar energy that is transmit-
ted through glazing under standard summer con-
ditions.

solar heating and cooling system An as-
sembly of (subsystems and components) which
converts solar energy into thermal energy for use
in combination with an auxiliary source of
energy, where required, for heating and cooling a
building.

solar house A dwelling designed to utilize
the sun's rays to maximum advantage for heat-
ing the house and providing hot water; an aux-
iliary heat source is usually provided; see active
solar-energy system and passive solar-energy
system.

solarium A sunny room with more glass than
usual, esp. one used for therapy.

solar orientation The placing of a building in
relation to the sun; depending on the geograph-
ical area, the building may be oriented to maxi-
mize the amount of heat gained from solar
radiation during the coldest months, or it may be
oriented to minimize the amount of heat gained
in the warmest months.

solar reflective glass See reflective glass.

solar resistance That property of a material
which resists decomposition resulting from
(a) the exposure to the sun's ultraviolet rays
and/or (b) the heat absorbed by exposure to the
sun's rays.

solarscope Same as heliodon.

solar screen l.A nonstructural openwork or
louvered panel of a building arranged so as to act
as a sun-shading device. 2. A perforated wall
used as a sunshade.

solar screen tile Tile manufactured for ma-
sonry screen (perforated wall) construction.

solar thermal collector See solar collector.

solar water heater A system in which the
sun's heat is gathered by a solar collector and
used to increase the temperature of a heat-trans-
fer fluid (such as water or a nonfreezing liquid)
which flows through the pipes in the collector;
the heat contained in this fluid then is conveyed
and transferred to the water to be heated. Also
see direct solar water heating system and indi-
rect solar water heating system.

solder An alloy, usually having a lead or tin
base, which is used to join metals by fusion; has
a melting point which does not exceed 800°F
(427°C).

908

solepiece

Collector

solar water heater

soldered joint A gastight metal-pipe joint,
made by soldering materials.

soldered joint formed with a hlowtorch

soldering flux Same as flux, 1 .

soldering gun An electrically heated soldering
iron with a pistol grip which reaches its operating
temperature rapidly; has a relatively small bit.

soldering gun

soldering iron A tool for joining metals with
solder; has a wedge-shaped metal bit, usually of
copper, which is heated.

soldering nipple A pipe nipple which is
threaded on one end and unthreaded on the
other; the plain end is soldered to the end
of a pipe.

solderless connector See pressure connector.

solder nipple Same as soldering nipple.

soldier 1. A brick that is laid on end, i.e., posi-
tioned vertically with its narrower face showing
on the wall surface; compare with sailor. 3. Same
as soldier pile.

SOLDIER

soldier, 1

soldier arch A flat arch in brick, having the
stretchers (long sides) of the uncut bricks set
vertically.

soldier beam A steel section which is driven
into the ground vertically; supports a horizon-
tally sheeted earth bank.

soldier course A course of upright bricks with
their narrow faces showing on the wall surface.

soldier pile, soldier l.In excavation work, a
vertical member which takes the side thrust
from horizontal sheeting or from walings and
which is supported by struts across the excava-
tion. 2. A vertical member used to prevent the
movement of formwork; is held in place by
struts, bolts, or wires.

sole 1. Same as solepiece. 2. Same as soleplate.

solea A raised walkway between the ambo and
bema in an Early Christian or Byzantine church.

solenoid valve A valve which is opened by a
plunger whose movement is controlled by an
electrically energized coil; the valve may be
closed by the action of a spring, by gravity, or by
an electrically energized coil.

solepiece 1. A horizontal member used to dis-
tribute the thrust of one or more uprights, posts,

909

soleplate

or struts. 2. A member on which the foot of a
raking shore rests.
soleplate l.Same as solepiece. 2. A horizontal
timber which serves as a base for the studs
in a stud partition. 3. A plate riveted to the bot-
tom flange of a plate girder to bear on the
masonry plate.

SOLE-
PLATE

soleplate, 2

soler Middle English term for solar.

solid bearing The continuous support for a
beam, along its entire length.

solid block A masonry block which meets the
specifications for a solid masonry unit.

solid-borne sound See structure-borne sound.

solid brick A brick which meets the specifica-
tions for a solid masonry unit.

solid bridging See block bridging.

solid concrete block A concrete solid ma-
sonry unit.

solid-core door A door having a core of solid
wood or mineral composition, as opposed to one
of hollow-core construction.

solid door Same as solid-core door.
solid floor See solid-wood floor.

solid frame A door or window frame made
from a single piece of timber as distinguished
from one that is built up in sections.

solid glass door A door in which the glass pro-
vides all or part of the structural strength.

solid masonry unit 1. (US) A masonry unit
whose net cross-sectional area in every plane
parallel to the bearing surface is 75% or more of
its gross cross-sectional area measured in the

DOOR

VENEER

CROSSBANDING

SOLID WOOD CORE

olid-

core door

same plane. 2. (Brit.) A solid masonry unit hav-
ing small holes, less than 54 in. (2 cm) wide or
less than % sq in. (5 sq cm) in area, passing
through it but not exceeding 25% of its vol-
ume, or having frogs that do not exceed 20% of
its volume. Up to three larger holes, not
exceeding 5 sq. in. (32.5 sq cm) each, may be
incorporated as aids to handling, within the
total of 25%.

solid masonry wall A wall built of solid
masonry units, laid contiguously, with joints
between completely filled with mortar.

solid molding See struck molding.

solid mopping In roofing, the application of
hot bitumen over an entire roof surface, leaving
no areas uncovered.

solid newel A newel into which the ends of a
winding stair are built, as distinguished from a
hollow newel.

solid-newel stair A type of spiral stair whose
wedge-shaped treads (fliers) wind around, and
are supported by, a central post (i.e., a newel);
also called a newel stair.

solid panel A panel which is flush with the
faces of the stiles of a door; also see flush panel.

solid partition A partition which contains no
voids.

solid plasterwork Plaster that is formed in
place and has a solid core.

solid punch A steel rod used to drive bolts out
of holes.

910

solvent wiping

solid rib In the centering of a large arch, a pro-
file of solid timber framing.

solid roll A joint in sheet-metal roofing made
over a wood roll, 2.

solids Residual matter in a paint film consisting
of pigments, resins, oils, driers, etc., after the
volatile water or solvent has evaporated.

solid- sawn lumber Lumber which has been
sawn from logs as opposed to lumber that has
been reprocessed.

solids content 1 . The percentage of solids in a
liquid mix, as in an adhesive. 2. In adhesives,
coatings, or sealants, the percentage of non-
volatile material.

solid-state welding Any welding process in
which coalescence is produced without the addi-
tion of a brazing filler metal at temperatures
below the melting point of the base metals being
joined; sometimes pressure is used.

solid stop A doorstop, 1 which is integral
with the doorframe; formed by a rabbet in the
frame.

solid strutting See block bridging.

solidum The dado of a pedestal.

solidus The highest temperature at which a
metal is completely solid.

solid wall l.See solid masonry wall. 2. A wall
of solid concrete.

solid waste A collective term for garbage,
refuse, rubbish, and trash, each term representing
a definite category of solid-waste materials
according to the classification established by the
National Solid Waste Management Association.

solid web A web composed of one or more

solid plates.

solid-web steel joist A steel truss having a
solid web, formed by a rolled section or plate.

solid-wood floor l.See plank-on-edge-floor.
2. A floor of wood block.

sollar, soller Same as solar.

Solomonic order See spiral column.

soluble drier, liquid drier A liquid that is
soluble in oil or in solvent-based paints and acts
as a drier.

solum The uppermost layer of soil.

solute, dissolved solids Solid particles of
material (i.e., dissolved salts and dissolved

organic materials) having a mean diameter of

less than 0.000001 mm that are dissolved in

water.
solvency, solvent power The degree to

which a solvent holds a resin or other paint

binder in solution, or reduces its viscosity.
solvent A liquid used to dissolve a solid (such as

a paint resin) so that it is brushable; usually

volatile; evaporates from the paint film after

application; a thinner,
solvent-activated adhesive A dry adhesive

film that is rendered tacky, just prior to use, by

application of a solvent.

solvent adhesive An adhesive having a vol-
atile organic liquid as a vehicle.

solvent molding The process of forming ther-
moplastic articles by dipping a mold into a solu-
tion of the resin and then drawing off the
solvent, leaving a layer of plastic film adhering
to the mold.

solvent power See solvency.

solvent-release sealant A sealant that cures
primarily through the evaporation of the solvent
it contains.

solvent-weld joint A pipe joint made by
spreading a cement on two plastic surfaces to
be joined. The cement reacts chemically with
these surfaces, thereby dissolving the material.
Then these two surfaces are placed in contact;
a solid joint is formed when hardening takes
place.

Wiped bead

Plastic pipe

Area of solvent
application

solvent-weld joint

solvent wiping Removing oil, grease, or dirt
from a surface with a cloth that has been soaked
in solvent.

911

sommer

sommer Same as summer,
sommering The joints radiating from the soffit
of a flat arch.

sone A unit of loudness.

sonic modulus Same as dynamic modulus of
elasticity.

sonic pile driver A device for driving piles
into soil by means of a hammer whose head is
vibrated (usually at a frequency less than 6,000
times per minute); this vibration is transmitted
to the tip of the pile, resulting in a penetration
that is relatively rapid and quiet.

soot door An access door to a flue for cleaning
and repairing the area traversed by flue gases.
Also see ashpit door.

soot pocket At the foot of a chimney, the
place where soot collects below the smoke inlet,
usually fitted with a door so that the soot can be
removed conveniently.

SOOT
POCKET

SMOKE
PIPE

soot pocket

sopraporta See overdoor.

sorel cement See oxychloride cement.

sorportales Roofed walkways around a cloister
or building, or a portion of such an encir-
clement.

sough A small drain at the foot of an embank-
ment; carries the surface water from it to a side
drain.

sound An oscillation in pressure of the atmo-
sphere which is capable of being detected by the
human ear.

sound absorption 1. The process of dissipat-
ing sound energy by converting it to heat. 2. A
property possessed by materials or objects of
absorbing sound energy. 3. A measure of the
magnitude of the absorptive property of a mate-
rial or object; expressed in sabins or metric
sab ins.

sound absorption coefficient, OC The frac-
tion of the sound energy (incident at random
angles on a surface) which is absorbed or other-
wise not reflected by the surface.

sound-amplification system A combina-
tion of one or more microphones, amplifiers,
loudspeakers, and associated electronic controls;
used to increase the level of a sound source so
that it may be heard clearly in all parts of an
auditorium, large room, open-air theater, etc.

sound analyzer An instrument used to mea-
sure the distribution of sound over the audible
frequency range, i.e., used to obtain a sound
spectrum.

sound attenuating door Same as sound-
rated door.

sound attenuation The reduction in the
intensity or in the sound pressure level of sound
which is transmitted from one point to another.
Also see sound insulation.

sound attenuator In ductwork, a device (usu-
ally prefabricated) especially designed to provide
much greater sound attenuation than would be
provided by an equal length of ductwork; the
pressure drop through the device is greater than
for an equal length of ductwork.

sound barrier Any solid obstacle which is rel-
atively opaque to sound that blocks the line of
sight between a sound source and the point of
reception of the sound.

sound-control booth A room, usually in or
adjacent to an auditorium, containing the sound-
control console and associated equipment.

sound-control console A console, 3 used to
control the sound-amplification system in an
auditorium.

sound-control glass See sound-insulating glass.

sound deadening See sound insulation.

912

sound reduction index

sound deadening board Any material, in
board form, used as a component in sound-insu-
lating construction.

sound door See sound-rated door.

sound focus A relatively small area in a room
or auditorium where the sound level is signifi-
cantly higher than elsewhere.

sounding board A solid flat surface above a
pulpit of an early church, intended to act as a
sound reflector, directing a small fraction of
sound of the speaker's voice toward the
listeners.

sound-insulating glass 1. Glass consisting of
two or more lights which are fixed in resilient
mountings, separated by spacers, and sealed so as
to leave an air space between them; the air space
contains a dessicant to assure dehydration of the
trapped air. 2. A single glazing unit consisting of
a thick sheet of plate glass that has been lami-
nated with a plastic.

sound insulation, sound isolation l.The
use of structures and materials designed to
reduce the transmission of sound from one room
or area of a building to another or from the
exterior to the interior of a building. 2. The
degree by which sound transmission is reduced
by means of sound-insulating structures and
materials.

sound intensity The average rate of sound
energy transmitted in a specified direction
through a unit area normal to this direction at
the point considered.

sound isolation See sound insulation.

sound knot, tight knot An undecayed, solid,
dead knot at least as hard as the surrounding
wood, and firmly held in place.

sound leak The passage of sound through a
crack or hole in a partition; significantly
reduces the effectiveness of sound insulation of
the partition.

sound level The reading of a sound-level
meter, using one of the three weighting net-
works; expressed in decibels (abbr. dB); the
weighting network used must be specified; the
most widely used network for noise measure-
ments is the A-network.

sound-level meter An instrument for the mea-
surement of noise levels and sound levels, whose
characteristics are specified by the American

National Standards Institute; the instrument
includes a microphone, amplifier, an output meter,
and three electrical networks (called weighting
network A, B, and C) which weight different
frequency components differently.

sound lock A vestibule or entranceway which
has highly absorptive walls, ceiling, and a car-
peted floor; used to reduce the transmission of
noise into an auditorium, studio, or rehearsal
room from the area outside.

soundness l.The freedom of a solid from
cracks, flaws, fissures, or variations from an
accepted standard. 2. In cement, freedom from
excessive volume change after setting. 3. In an
aggregate, the ability to withstand the aggressive
action to which concrete containing it might be
exposed, particularly that due to weather.

sound power Of a source of sound, the total
amount of acoustical energy radiated per unit
time.

sound-power level The level, 4 of sound
power, averaged over a period of time, the refer-
ence level being 10~ 12 watt.

sound pressure The minute fluctuations in
atmospheric pressure which accompany the
passage of a sound wave and give rise to the
sensation of hearing; usually expressed in dynes
per square centimeter or newtons per square
meter.

sound-pressure level The level, 4 of sound
pressure; equal to 10 times the logarithm of the
sound pressure squared and averaged over a
period of time, the reference pressure being
0.0002 dyne per sq cm (2 x 10~ 5 newton per sq
m); expressed in decibels (abbr. dB).

soundproofing The elements of construction
and the design features of a building which make
it relatively impervious to sound transmission
from one room to another or from outside the
building to the inside.

sound-rated door A door especially constructed
to provide greater sound attenuation than that
provided by a conventional door; usually carries a
rating in terms of its sound transmission class.

sound ray An imaginary line emanating from a
sound source which indicates the direction of
propagation of the sound waves.

sound reduction index, R British term for
sound transmission loss.

913

sound-reinforcement system

sound-reinforcement system Same as
sound-amplification system.

sound-resistive glass See sound-insulating
glass.

sound-retardant door See acoustical door
and sound-rated door.

sound spectrum A representation of the mag-
nitude of the components of a complex sound as
a function of frequency.

sound transmission The passage of sound
from one point to another, e.g., from one room
in a building to another, or from the street into a
room in the building.

sound transmission class, STC A single-
number rating of the sound insulation value of a
partition, door, or window; it is derived from a
curve of its insulation value as a function of fre-
quency; the higher the number, the more effec-
tive the sound insulation.

sound transmission loss, transmission
loss, TL A measure of the sound-insulation
value of a partition; the amount, in decibels, by
which the intensity of sound is reduced in trans-
mission through the partition.

sound trap Same as sound attenuator.

sound waves In air, a succession of outwardly
traveling layers of compression and rarefaction,
capable of being detected by the ear.

sound weighting network See weighting
network.

sound wood Wood free from decay.

souse, souste Same as corbel.

south aisle The aisle of a church on the right
side as one faces the altar; so called because
medieval churches almost invariably had their
sanctuaries at the east end and the main doors at
the west end.

SOUTH PORCH

south aisle; south porch

south door A small door into the chancel (for
the priest), usually on the south side of the
church leading to his residence.

Southern Building Code Congress Inter-
national See SBCCI.

Southern Colonial house 1 . Any prerevolu-
tionary house in the tradition of American Colo-
nial architecture of the early South. 2.
Descriptive of a full-colonnaded Greek Revival
style mansion, usually constructed after the colo-
nial period. Also see plantation house.

southern pine Same as yellow pine.

south-light roof In the southern hemi-
sphere, a sawtooth roof in which the glazing
faces south.

south porch A porch which shelters the
entrance to a church; located on the right side of
the church as one faces the altar.

south side In a church, the side to the right of
an altar as one faces the altar.

SOV Abbr. for "shutoff valve."

Sovent system A single-stack plumbing sys-
tem used for both drainage and venting.

SOX lamp See sodium-vapor lamp.

soya glue, soybean glue A vegetable protein
glue made from extracted soya bean meal; has
greater adhesive power than most other veg-
etable glues and is more water-resistant than veg-
etable pastes; marketed dry; used for interior
plywood.

soybean oil, soya-bean oil A pale yellow
drying oil obtained from soya beans; used in
paints and varnishes; sometimes mixed with lin-
seed oil.

SP 1. Abbr. for soil pipe. 2. Abbr. for standpipe.

SPA Abbr. for "Southern Pine Association."

space diagram A drawing of a structure that
indicates its form as well as means of its support
and loading conditions.

spaced slating See open slating.

spaced steel column A battened column in
which the battens are attached to the longitudi-
nal column elements by hinged connections.

space frame Any three-dimensional struc-
tural framework (e.g., the rigid frame for a mul-
tistory building) as contrasted with a plane
frame all of whose elements lie in a single
plane.

914

spandrel glass

space heater A relatively small self-con-
tained heater, usually with a powerful fan, used
to heat the room or space in which it is placed;
electricity or a liquid fuel supplies the heat
energy.

space lattice A space frame constructed of lat-
tice girders.

spacer 1. In glazing, one of the small blocks of
wood or other material placed on both sides of
the edges of glass, during its installation, to cen-
ter it, to maintain uniform width of sealant
beads, and to prevent excessive sealant distor-
tion under lateral loading. 2. A device which
holds steel reinforcement in its proper position,
or which holds wall forms at a given distance
apart before and during concreting. 3. See edge
spacer. 4. See shim spacer.

space truss A three-dimensional truss.

spachtling See spackle.

spackle, spachtling, spackling, sparkling

A paste, compound, or powder which can be
mixed into a paste; used to fill holes, cracks, and
defects in wood, plaster, wallboard, etc., to
obtain a smooth surface.

spade A tool for digging and cutting the ground,
having a rather thick blade, usually nearly flat,
so formed that its terminal edge may be pressed
into the ground with one foot while the handle
is grasped.

spading Consolidation of mortar or concrete as
the result of repeated insertions and withdrawals
of a flat, spade-like tool.

spall A small fragment or chip removed from
the face of a stone or masonry unit by a blow or
by action of the elements.

spalled joint A masonry joint using mortar
containing cementitious material, water, and an
aggregate consisting largely of spalls.

spalling The flaking of bricks, concrete, or
stone through deterioration, usually as a result of
frost, chemical action, or the movement of a
building structure.

spalling hammer A heavy ax-like hammer
with a chisel edge; used for the rough dressing of
stone by chipping off small flakes.

span 1 . The interval between two terminals of
a construction. 2. The distance apart of any
two consecutive supports, esp. as applied to the

opening of an arch. 3. A structural member (or
part of a member) between two supports.
spandrel, spandril l.An area, roughly trian-
gular in shape, included between the extradoses
of two adjoining arches and a line approximately
connecting their crowns (or a space approxi-
mately equal to half this in the case of a single
arch); in medieval architecture, often orna-
mented with tracery, etc. 2. In a multistory build-
ing, a wall panel filling the space between the top
of the window in one story and the sill of the
window in the story above. 3. A surface, roughly
triangular in shape, as below a stair string.

JL,

mmmmSimmm

mmmmmm

spandrel, 1

spandrel beam In concrete or steel construc-
tion, an exterior beam extending from column
to column usually carrying an exterior wall load.

spandrel face The exposed portion of a span-
drel, 1.

spandrel frame Framing which is triangular in
shape.

spandrel glass An opaque glass used in win-
dows and curtain walls to conceal spandrel
beams, columns, or other internal construction.

915

spandrel panel

spandrel panel A panel covering a spandrel
area.

spandrel step A solid step, triangular in sec-
tion, whose hypotenuse forms part of the sloping
soffit of the stair flight.

spandrel wall l.A wall built on the extrados
of an arch, filling in the spandrels. 2. That por-
tion of a skeleton wall above the head of a win-
dow or door.

Spanish Colonial architecture Architec-
ture, particularly in those areas of the American
continents that have been subject to Spanish
influence; greatly affected by local culture, cus-
toms, traditions, and availability of materials.
Spanish Colonial architecture in the American
southwest usually is typified by thick, solid
adobe walls, often covered with a protective
layer of stucco or plaster; a one-story building
around an enclosed courtyard; a long, narrow,
covered porch either facing the street or facing a
patio; often, a balcony, commonly supported by
columns at ground-floor level, each column usu-
ally topped with a bolster; commonly, flat roofs
supported by round logs drained by waterspouts
that penetrated the parapet surrounding the
roof; low-pitched or medium-pitched roofs cov-
ered with red clay tiles, often with a substantial
overhang, were also common; windows facing
the street usually protected by ornamental
grillwork; doors to the various rooms opened
directly onto a covered porch or onto a patio.
Also see azotea, board house, canale, Chur-
rigueresque style, common house, conch house,
coquina, galeria, Monterey style, palma hut,
plank house, Plateresque architecture, Saint
Augustine house, tabby, tabla house, viga,
zaguan, zambullo door.

Spanish Colonial Revival An eclectic style
loosely based on one or more phases of Spanish
Colonial architecture; most common from about
1915 to the present. Buildings in this style usu-
ally characterized a facade with unadorned
stucco or plastered walls; glazed and/or unglazed
wall tiles; a covered porch or arcade; commonly,
a patio; wrought-iron balconies or balconets;
often, a low- to moderate-pitched, mission-tiled,
hipped and/or gable roof multicurved mission
parapets with decorative tilework along the
outer face of the parapet; round arches over the
most prominent windows; often, rectangular

Spanish Colonial Revival

windows with lintels, sometimes crowned with
an enriched cornice; window grilles; ornate,
low-relief window surrounds; heavy wood doors,
often elaborately paneled or carved; frequently,
rounded arches over the exterior doors; French
doors providing easy access to a patio, balcony,
or outdoor terrace.
Spanish console A wrought-iron console, 1
that supports a balcony.

Spanish Eclectic architecture Same as, or

an early phase of, Spanish Colonial Revival.

Spanish Mission Revival, Spanish Mission
style See Mission Revival.

Spanish Pueblo Revival Same as Pueblo
Revival; also see Spanish Colonial Revival.

Spanish Territorial style See Territorial style.

Spanish tile l.A red roofing tile whose hori-
zontal cross section has the shape of the letter S
laid on its side. 2. Same as mission tile.

spanner, span piece A horizontal cross brace
or collar beam.

span piece 1 . In a collar-beam roof, the hori-
zontal beam which connects the rafters. 2. A
collar-beam.

span rating The distance that a building panel
spans between supports.

span roof A pitched roof, both sides of which
have the same slope.

spar l.A common rafter. 2. A bar for fastening
a gate or door. 3. A heavy round timber. 4. See
brotch.

spar dash Same as rock dash.

spar finish Said of a roof surface that is a good
reflector of sunlight; for example, a roof surface
having a stone chip finish.

916

specific modulus

sparge pipe A perforated water pipe used to
flush a urinal.

spark arrester A device (located at the top
of a chimney) to prevent sparks, embers, or
other ignited material above a given size from
being expelled to the atmosphere. Also called
a bonnet.

sparkling See spackle.

spar piece Same as span piece.

sparpiece See collar beam.

sparrow peck A textured finish, produced on
a plastered surface by dabbing the surface with a
stiff brush.

spar varnish A varnish made with durable oils
and resins; used on exterior wood surfaces because
of its superior weather-resistant qualities.

spat A protective covering (usually stainless
steel) at the bottom of a doorframe to prevent or
minimize damage in this area.

spatter dash 1. A wet mixture of cement and
sand, thrown on a smooth surface; when hard it
provides a key for a plaster coat. 2. A finish pro-
duced by throwing a wet mixture of cement and
sand on fresh mortar.

spawl Same as spall.

speaking rod Same as self-reading leveling rod.

speaking tube A tube, usually of metal, used
to transmit the voice from one part of a building
to another, before the days of electronics.

SPEC On drawings, abbr. for specification.

special assessment A compulsory charge
imposed by a government upon the owners of
a restricted group of properties to defray the
cost of a specific improvement or service,
presumably of general benefit to the public
and of special benefit to the owners of such
properties.

special conditions A section of the condi-
tions of the contract, other than general condi-
tions and supplementary conditions, which may
be prepared for a particular project. Also see
conditions of the contract.

special hazards insurance Additional per-
ils insurance to be included in property insur-
ance (as provided in contract documents or
requested by contractor or at option of owner)
such as sprinkler leakage, collapse, water dam-
age, all physical loss, or insurance on materials

and supplies at other locations and/or in transit
to the site.
special matrix terrazzo Flooring consisting
of colored aggregate and organic matrix.

special moment frame A frame whose mem-
bers and joints are able to resist flexural forces as
well as axial forces.

special provisions See special conditions.

special-purpose industrial occupancy Indus-
trial occupancy for particular types of operations,
characterized by a relatively low density of
employee population, with much of the area occu-
pied by machinery or equipment; highly hazardous
usage is excluded.

special-quality brick Brick that is durable
even when used under extreme conditions of
exposure, as in the case of a structure that
becomes water-saturated and/or frozen.

special waste Any waste that requires special
treatment before being fed into a normal
drainage system.

specification A written document describing
in detail the scope of work, materials to be used,
method of installation, and quality of workman-
ship for a parcel of work to be placed under con-
tract; usually utilized in conjunction with
working (contract) drawings in building con-
struction.

specifications A part of the contract docu-
ments contained in the project manual consist-
ing of written descriptions of a technical nature
of materials, equipment construction systems,
standards, and workmanship. Under the uni-
form system, the specifications comprise sixteen
divisions.

specific gravity 1 . The ratio of the density of a
substance to the density of a reference material
(usually water for liquids and air for gases). 2. As
applied to a gas piping system, the ratio of the
weight of gas of a given volume to the weight of
the same volume of air, both measured under the
same conditions.

specific heat The ratio of the quantity of heat
required to raise the temperature of a given mass
of any substance 1 degree to the quantity
required to raise the temperature of an equal
mass of water 1 degree.

specific modulus The modulus of elasticity of
a material divided by its density.

917

specific resistance

specific resistance See electrical resistivity.

specific retention The percentage of water
which will be retained by rock or soil (against
the pull of gravity) after being saturated; com-
puted in terms of the ratio of volume of water
retained to its own value.

specific strength The ultimate strength of a
material divided by its density.

specific surface In a unit weight of a material,
the surface area of the contained particles.

specific yield The percentage of water which
will be yielded by a rock or soil (by gravity)
after being saturated; computed in terms of the
ratio of the volume of water retained to its own
volume.

specifier One who writes or prepares specifica-
tions for building construction.

SPECSystem A (proprietary) interactive ex-
pert system for writing specifications in the
CSI's 16-division format.

SPECTEXT A (proprietary) guide specifica-
tion published by the Construction Specifica-
tion Institute (CSI); published in the CSI's
16-division format.

spectral power distribution In illumination
engineering, the distribution of radiant power
(commonly expressed in watts per nanometer)
with respect to wavelength.

E
= SO

vJJ L — '

400 500 600 700

WAVELENGTH , NANOMETERS

spectral power distribution: deluxe warm white
fluorescent lamp

spectrophotometer An instrument for mea-
suring the reflectance and transmittance of
surfaces and media as a function of wave-
length.

specular angle The angle between the per-
pendicular to the surface and the reflected ray
that is numerically equal to the angle of inci-
dence and lies in the same plane as the inci-

specular angle: angle of incidence, I, equals the angle of
reflection, R

dent ray and the perpendicular, but on the
opposite side of the perpendicular to the
surface.

specularia Windowpanes used in ancient
Rome; usually made of thin sheets of mica (lapis
specularis).

specular surface A mirror-like surface which
reflects light at an angle equal to that of the inci-
dent light.

speculative builder One who develops and
constructs building projects for subsequent sale
or lease.

specus In early Roman architecture, the cov-
ered channel of an aqueduct in which water
flows.

speer See spere.

spelter Same as zinc.

speos In ancient Egypt, a temple or part of a
temple, or a tomb of some architectural impor-
tance, excavated in solid rock; a grotto temple
or tomb.

spere, speer, spier, spur In medieval English
residences and derivatives, a fixed screen pro-
jecting from the side of a great hall, near a door,
to mitigate drafts and to screen the door's
entrance.

spere-truss In a medieval hall of timber con-
struction, a roof-supporting wooden arch, rising
from trusses attached to the sidewalls, marking
the division between the principal area of the
hall and the screens passage.

sperone A buttress.

spewing The formation of a film, or the collec-
tion of particles, on a paint surface; results from
the migration, to the surface, of the insoluble
portion of the paint binder.

SP GR On drawings, abbr. for specific gravity.

sphaeristerium In ancient Rome, an en-
closed place or structure for ball playing,

918

spindle sander

usually attached to a gymnasium or a set of
baths.

spherical vault A dome shaped like a half
globe.

sphinx In Egyptian antiquity, a figure having
the body of a lion and a male human head, or an
animal head; commonly placed in avenues lead-
ing to temples or tombs; the most celebrated
example is the Great Sphinx near the pyramids
of Giza, near Cairo.

spicae testaceae Oblong bricks for pavements,
used in spicatum opus.

spicatum opus Ancient Roman masonry laid
in a herringbone pattern.

spicatum opus

spier See spere.

spigot 1 . A faucet. 2 . The end of a pipe that fits
into a bell, 2.

.SPIGOT sTTfik

spigot, 2

spigot-and-socket joint See bell-and-spigot

joint.
spigot joint See bell-and-spigot joint.

spike A very heavy nail, 3 in. (7.6 cm) to 12 in.
(30.5 cm) in length, usually having a rectangular
cross section.

spike-and-ferrule installation A type of
gutter installation in which the gutter is fastened
by means of long nails and metal sleeves.

spiked-and-linked chain A heavy chain,
usually wrought iron, with spikes alternating
with links; attached to posts to enclose a garden.

spike-and-ferrule installation

spike grid A type of timber connector.

spike knot, splay knot An elongated knot;
the result of cutting wood approximately parallel
to the length of the knot.

spile 1. A peg or plug used to fill a nail hole. 2.
Same as pile.

spiling Same as piling.

spill, spill light Light rays, from spotlights and
other focused light sources, that are not useful,
e.g., producing lighting where it is not wanted
on a stage.

spill ring See ring louver.

spill shield A type of louver, 1 to prevent the
spill of light.

spina A barrier dividing an ancient Roman cir-
cus lengthwise, about which the racers turned.

spindle l.A slender rod or pin on which any-
thing turns, as the shaft to which a doorknob is
attached. 2. On a lock mechanism, the bar con-
nected with the knob or lever handle that passes
through the hub of the lock or otherwise engages
the mechanism to transmit the knob action to the
bolt(s). 3. In woodworking, a short turned part as
in a baluster.

spindle sander A sanding machine in which
the sandpaper is carried on a small-diameter ver-
tical drum located on the work table of the
machine.

919

spindlework

spindlework Wood details having circular
cross sections, such as balusters turned on a
lathe; occasionally called spoolwork.

spindlework on porch

spine wall A load-bearing wall running parallel

to the long axis of a building.
spinning house A subsidiary building once

devoted exclusively to spinning or weaving; also

called a loom house or a weaving house.
S-pipe Same as offset elbow.
spira The moldings at the base of a column;

a torus.
spiral A continuously wound reinforcement in

the form of a cylindrical helix.
spiral balance A sash balance using a spirally

wound helical spring to compensate for the

weight of the sash.
spiral column See barley-sugar column, calo-

monica, torso.
spiral grain Grain following a spiral course, in

one direction, around the axis of a tree; produces

highly figured veneer.
spirally reinforced column A column

whose vertical reinforcing bars are enveloped by

spiral reinforcement.
spiral ratchet screwdriver A screwdriver

having a blade that rotates with respect to the

handle, as the handle is pushed inward toward

the blade; permits a screw to be driven easily and

with speed.
spiral reinforcement Coiled steel wire or bar,

bent to a definite pitch or spacing; used as rein-
forcement in reinforced concrete.

spiral stair, caracole, circular stair, cockle
stair, corkscrew stair, spiral staircase A

flight of stairs, circular in plan, whose treads
wind around a central newel. Also called a heli-
cal stair, solid newel stair.

spiral stair

spiral tower A spiral staircase in a Gothic
tower.

spire Any slender pointed construction sur-
mounting a building; generally a narrow octago-
nal pyramid set above a square tower.

spirelet A small spire as of a pinnacle or turret.

spirelight A small, glazed opening set into the
tapering side of a church spire; frequently used
in the Early English style, commonly used in
the Decorated style, and occasionally used in
churches of the Perpendicular style.

spire-steeple A spire atop a steeple.
spiriting off In finishing with French polish,

rubbing the surface lightly with a rag soaked in
methylated spirit.

spirit level A closed glass tube of circular cross
section, usually set in a device or instrument;
nearly filled with liquid, so that a bubble is
formed, the centering of which is used to deter-
mine true horizontal or vertical directions;
a level.

spirits of turpentine See turpentine.

spirit stain A penetrating, alcohol-soluble dye
used to stain wood, producing deep color and lit-
tle fiber swelling.

spirit varnish A varnish which uses a highly
volatile liquid as the solvent for the resin or oil.

spitter See lead spitter.

SPKR On drawings, abbr. for loudspeaker.

920

splice box

SPL On drawings, abbr. for "special."
splashback Same as splashboard.

splash block A small masonry block laid on
the ground below a downspout to carry roof
drainage away from a building and to prevent
soil erosion.

«";.■ iSpSSPLASH-
splash block

splashboard A board which provides protec-
tion against water splashes, as behind a sink.

splash brush In plastering, a brush for applying
water on a finish coat while it is being smoothed
with a trowel.

splash lap In sheet-metal roofing, that part of a
seam in a drip or roll that extends onto the flat
surface of the next sheet.

splat A strip which covers the joints between
adjacent sheets of building board.

splatter-dash Said of a rough, plaster wall sur-
face onto which small lumps of wet plaster have
been flicked before the wall was fully dry.

splay A sloped surface, or a surface which makes
an oblique angle with another, esp. at the sides
of a door, window, proscenium, etc., so the open-
ing is larger on one side than the other; a large
chamfer; a reveal at an oblique angle to the exte-
rior face of the wall.

splay brick, cant brick A brick, one side of
which is splayed (beveled).

splayed arch An arch opening which has a
larger radius in front than at the back.

splayed baseboard A baseboard having its
upper edge beveled.

splayed coping See featheredged coping.

splayed-foot spire A spire having sides that
splay outward at its base.

splayed ground A plaster ground having
undercut edges which provide a key for holding
the plaster more securely.

splayed heading joint An overlapping joint
between boards; their ends are cut at an angle of
45° rather than 90° as in a butt joint.

splayed jamb Any jamb whose face is not at
right angles to the wall in which it is set.

splayed joint A joint between the ends of two
adjacent members, each of which is splayed so
that the cross-sectional area of the members is
unchanged at the joint.

splayed lintel A lintel (i.e., horizontal struc-
tural member above a window) each end of
which slants downward toward a centerline
through the window; often has a keystone at its
center.

splayed lintel with a keystone at its center

splayed mullion A mullion joining two glazed
units which are at an angle to each other, as the
mullion of a bay window.

splayed skirting A baseboard having its upper
edge beveled.

splayed window A window whose frame is set
at an angle with respect to the face of the wall.

splay end The smaller end of a splayed ma-
sonry unit.

splay knot See spike knot.

splice To connect, unite, or join two similar
members, columns, pieces, wires, etc., usually in
a straight line, by fastening lapped ends by means
of mechanical end connectors, by welding, etc.

splice box l.Same as manhole. 2. Similar
to a manhole, but much smaller.

Ssrvic* coflduil and — ' | tf tf ■/" - j a p-\

- To meter al buiWng

- Spliw box
- Cflrtneclion

921

spliced pile

spliced pile A pile composed of two or more
segments that have been joined end-to-end to
form a single pile.

splice plate A metal plate used for fastening
two or more members together.

splice plate

spline, false tongue, feather, slip feather,
slip tongue 1. A long thin strip of wood or

spline, 1

Acoustical
tile

■ Spline

3fe

metal which is inserted in a slot formed by two
members, each of which is grooved and butted
against the other. 2. In a suspended acoustical
ceiling, a strip of metal or hard fiber inserted in
the slot between adjacent acoustical tiles which
butt against each other, forming a concealed
mechanical joint.

spline joint A joint formed by inserting a spline
in a slot cut into the two butting members.

split 1. A rupture in a built-up roof membrane,
resulting from tensile stresses. 2. A crack that
extends completely through a piece of wood or
wood veneer. 3. A brick cut lengthwise, in two
pieces, parallel to the wide face of the brick, so
that it is half as thick; also called scone.

spline, 2

split, 3

split astragal A vertical molding, attached to
the meeting edges of each of the leaves of a pair
of doors, for protection against weather; the split
feature permits both leaves to be active.

split-batch charging A method of filling a
concrete mixer in which the cement, and some-
times different sizes of aggregate, may enter the
mixer separately.

split block, split-face block A solid or hol-
low concrete masonry unit, split lengthwise after
curing; laid with the fractured surface exposed,
so as to provide a rough texture.

split-conductor cable A cable in which each
conductor consists of two or more insulated con-
ductors which are normally connected in parallel.

split course A course of splits, 3, i.e., bricks
cut so they are of less than normal thickness.

split dead bolt A dead bolt composed of two
pieces (each with its own control knob), one on
each side of a door.

split-face block See split block.

split- face finish A building stone having a rough
face; usually slabs of stratified stone are sawn paral-
lel to the bedding so that the split face exposes the
bedding in its natural orientation, but some stone

922

spot

is sawn perpendicular to bedding and then split
with the exposed bedding running vertically.

split-face machine A device for splitting
slabs of stone into usable thicknesses for job-
fabricated masonry patterns.

split fitting In interior electric wiring, a con-
duit fitting which is split longitudinally so that it
can be placed in position after the wires have
been drawn into the conduit; the two parts of
the fitting are held together with screws.

split frame, split jamb A doorframe with the
jamb split in two or more pieces; may be used to
enable a pocket-type sliding door or vertical slid-
ing sash to enter the partition.

split lath A wood lath made by splitting long
strips of wood; less uniform than wood lath cut
with a saw.

split-level house A house having its living
room area on the main floor, with stairs leading
upward to the bedrooms approximately a half-
story higher; and other stairs leading downward,
a half-story lower, to the kitchen and/or dining
areas and to a laundry or utility room; often has
no attic, cellar, or porch for reasons of economy.

split mold A mold whose cavity is formed by
two or more parts that are separable.

split pediment Same as broken pediment.

split pin Same as cotter pin.

split-rail fence See zigzag fence.

split-ring connector A ring-shaped metal
insert placed in precut circular grooves and held
by bolts; used as a timber connector.

split rivet A small rivet having a split end for
securing by spreading the ends; commonly fur-
nished with an oval or countersunk head.

split roof A roof constructed of strips split from
straight-grained timber.

split shake Same as shake, 1.

split stuff A timber cut to length and then split.

splitting A defect in a painted surface; results
from the penetration of solvents, contained in
a fresh coat of paint, into an older layer of
paint over which it has been applied; likely to
occur when the old layer has been sanded too
much.

splitting tensile strength The tensile strength
of concrete determined by a splitting tensile test.

splitting tensile test A test for tensile strength
in which a cylindrical specimen is loaded to fail-
ure in diametral compression.

splocket Same as sprocket.

spoil Material from excavating or dredging.

spoil area A site where excavated material is
deposited.

spokeshave A carpenter's tool; a kind of draw-
ing knife or planing tool having a blade set
between two handles; esp. used for shaping
curved edges.

BLADE

split-ring connector showing a typical joint

spokeshave

sponge rubber, foam rubber Expanded rub-
ber having a cellular structure; usually has inter-
connecting cells; used as resilient padding and as
thermal insulation.

spontaneous ignition The initiation of com-
bustion caused by internal, chemical reaction in
which heat is liberated.

spontaneous liquefaction See liquefaction.

spoolwork Same as spindlework.

spoon In plastering, a small steel tool, used in
finishing moldings by hand.

spoon bit See dowel bit.
spot See spotting.

923

spot board

spot board A mortarboard.

spot cementing The discontinuous applica-
tion of a cold-liquid cementing compound.

spot elevation A point on a map or chart
whose height above a specified reference datum
is noted, usually by a marker and elevation
value.

spot finishing See spotting in.

spot ground A piece of wood which is
attached to a plaster base to serve as a means of
gauging plaster thickness.

spot level Same as spot elevation.

spotlight A floodlight equipped with a lens and
one or more reflectors to provide a narrow beam
to illuminate a specifically defined area.

spotlight booth A booth in an auditorium
where spotlights are mounted and controlled.

spot mopping Mopping of a roofing surface
with hot bitumen in roughly circular areas about
IK ft (46 cm) in diameter, leaving a gridwork of
unmopped bands.

spot relamping The replacement of each lamp
in a lighting system, individually, at the time it
fails. Also see group relamping.

spotting A paint-film defect characterized by
small circular or irregular areas having color or
gloss different from that of the surrounding
background.

spotting in, spot finishing Repairing a small
area on a dry painted surface by blending a fresh
coat of paint with the dry coating.

spot-weld A weld between two overlapping
members at an isolated spot by means of heat
and pressure.

spout A short channel or tube used to spill
storm water from gutters, balconies, exterior gal-
leries, etc., so that the water will fall clear of the
building. Also see gargoyle.

spraddle Same as bonnet roof.

sprawl See urban sprawl.

spray booth An enclosed or semienclosed area
used for the spray painting of fabricated items;
may be equipped with a source of filtered air to
keep the atmosphere dust-free, a waterfall back-
drop to trap overspray, and an exhaust system to
vent the fumes of the evaporating solvents.

sprayed acoustical plaster An acoustical
plaster which has been applied with a special

spray gun to form a continuous surface, usually of
rough texture.

sprayed asbestos Asbestos fibers intermixed
with bonding and adhesive ingredients; applied
to surfaces such as structural beams with a spray
gun; serves primarily as fire protection. The use
of this material is no longer permitted in the
United States because of its carcinogenic effects.

sprayed concrete See shotcrete.

sprayed fireproofing A material which is
sprayed directly onto structural elements (or on
specially provided base, such as lath) to provide
increased fire endurance. Also see sprayed
asbestos.

sprayed insulation See spray-on insulation.

sprayed mortar See shotcrete.

spray gun A tool, operated with compressed air
or fluid pressure, which expels paint, mortar,
etc., through a small orifice, onto the surface
being coated. Also see concrete gun.

spray gun

spray lime A very fine hydrated lime; at least
95% of the particles pass through a No. 325
(45-jim) sieve.

spray-on insulation A mixture of mineral
fiber with other ingredients; applied by air pres-
sure with a spray gun; used to provide fire pro-
tection and/or thermal insulation.

spray painting Applying paint by means of a
spray gun; provides a very uniform film, can
cover evenly an object of irregular shape; esp.
useful for painting large areas or mass-produced
items.

spray pond An arrangement for lowering the
temperature of water by evaporative cooling; the
water to be cooled is sprayed by nozzles into a
pond of water, cooling in the air as it falls.

spray-pond roof A roof designed to retain
water in a spray pond, incorporating a system of
spray jets; used to cool the roof.

924

springer

spray sprinkler 1. In a fire sprinkler system, a
type of sprinkler that is listed for its capability to
provide fire control over a wide range of fire
hazards. 2. A sprinkler providing a parabolic
water distribution downward for a definite pro-
tection area; directs from 80 to 100 percent of
the total water flow initially in a downward
direction.

spread Of air supplied by a air diffuser in an air-
conditioned space, the divergence of the
airstream after it leaves the outlet.

spreadable life See pot life, 2.

spreader 1 . A machine for metering granular
material, such as gravel or crushed stone, from a
feed hopper and distributing it over a given area.
2. A brace between two wales. 3. A stiffening
member temporarily attached to the base of a
doorframe, extending between the jambs, to
keep the frame in proper alignment during ship-
ping and handling.

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spreaders, 2 in a wall form

spreader bar A stiffening member placed at
the base of a doorframe to keep it in alignment
during shipment and prior to installation.

spread footing A footing which is especially
wide, usually of reinforced concrete.

spreading rate l.The rate at which bitumen,
roof surfacing, or other material is applied to a
roof. 2. The area covered by a gallon of paint.

spread lens A lens at the front of a directional
luminaire or floodlight used to spread a rela-
tively narrow beam; may be part of the luminaire
or an auxiliary element.

spread-of-flame index See flame-spread
index.

spread-of-flame test A fire test of roof cover-
ings in which a specified large flame plays on a
test roof deck continuously while exposed to a
specified wind.

sprig A brad or nail without a head; also see
glazing sprig.

sprig bit Same as brad awl.

spring l.An elastic body or device (such as a
spirally wound metal coil) which stores mechan-
ical energy when it is compressed and imparts
this energy when it recovers its shape. 2. See
springing. 3. See crook, 1.

spring balance A sash balance in which the
weight of the sash is counterbalanced by the
force supplied by a spring.

spring bolt, cabinet lock A bolt having a
beveled face; retracts when subject to pressure
and springs back when the pressure is released; is
self-acting when the door or drawer is closed.

spring bow Same as bow compass.

spring buffer A buffer consisting of a spring
which stores and dissipates the kinetic energy of
an impact (such as that resulting from a
descending elevator car or counterweight that
strikes the spring).

spring clamp A clamp esp. used to hold materi-
als during gluing; similar to lightweight pliers in
which clamping pressure is exerted by a spring.

spring clamp

spring clip Same as resilient clip.

spring constant Of an elastic spring, the ratio
of the force applied on the spring to the resulting
displacement.

spring eaves Same as Dutch eaves.

springer, skewback, summer l.The impost
or place where the vertical support for an arch

925

spring floor

springer, 1 : S

terminates and the curve of the arch begins.
2. The lower voussoir, or bottom stone of an arch,
which lies immediately on an impost. 3. The bot-
tom stone of the coping of a gable. 4. The rib of a
groined roof or vault; also see cross-springer.

spring floor Same as resilient floor.

spring hanger See resilient hanger.

spring hinge A hinge containing one or more
springs; when a door is opened, the hinge returns
it to the open position automatically; may act in
one direction only, or in both directions (as on a
swinging door).

tn=

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spring hinges

springhouse A small structure, typically of
masonry construction, usually built into the
slope of a hillside and enclosing a natural spring;
the water flows into a small pool within the
springhouse, keeping it cool at all times, and
providing an excellent storage place for dairy
products and other perishable foods.

springing, spring l.The point where an arch
rises from its supports. 2. The angle of rise of an
arch.

springing course In masonry, the stones upon
which the first stones of an arch rest.

springing line The imaginary horizontal line
at which an arch or vault begins to curve; the
line in which the springers rest on the imposts.

_SPRING1NG_LINE

springing line

springing wall Same as a buttress.

spring latch A door latch that springs into
place when the door is closed.

spring line l.Same as springing line. 2. In a
transverse cross section of pipe, the line of max-
imum horizontal dimension.

spring lock A lock which fastens automatically
by a spring when the door or lid to which it is
attached is shut.

spring snib A spring-controlled sash fastener.

springwood Wood formed during the spring
and early summer; characterized by cells which
are larger and thinner than the cells formed later
in the year.

sprinkle The distribution of additional chips
on a terrazzo topping prior to rolling.

sprinkle mopping Mopping a roof surface
with hot bitumen in a pattern applied in parallel
bands.

sprinkler l.In a fire protection system, a
device designed to release a stream of water and
distribute it in a specified pattern and quantity
over a designated area; usually one of many
such outlet nozzles. 2. A fire-protection sprin-
kler system.

sprinkler alarm An alarm on a fire-protection
sprinkler system which sounds when there is
flow of water in the system.

sprinklered Said of an area of a building that is
equipped with a properly maintained automatic
sprinkler system.

926

square billet

sprinkler head One of the many outlet nozzles
in a fire-protection sprinkler system; in an auto-
matic system, each nozzle is closed by a fusible
plug that melts at a predetermined temperature;
in an open-head system the individual nozzles
are open, and a small group of nozzles is con-
trolled by an automatic valve.

sprinkler system A system (usually auto-
matic) for protection against fire which, when
activated, sprays water over a large area in a sys-
tematic pattern; an integrated system of over-
head and underground piping, designed in
accordance with fire protection engineering
standards, which includes: (a) one or more auto-
matic water supplies, (b) a network of specially
sized or hydraulically designed piping which is
installed (generally overhead) throughout the
building or area, (c) sprinklers (i.e., sprinkler
heads) distributed in a systematic pattern which
are attached to the piping, (d) a valve which
controls each system riser or its supply piping,
and (e) a device for actuating an alarm when the
system is in operation.

sprinkler valve See fire-protection sprinkler

valve,
sprocked eaves The eaves of a roof which

have been raised by sprockets.

sprocket, cocking piece, sprocket piece

In roofing, a strip of wood, fixed to the upper
side of rafters at the eaves; raises the edge of the
eaves and forms a break in the roof line.

spruce, Norway spruce, spruce fir, white
deal, white fir A white to light brown or
red-brown, straight- and even-grained wood;
moderately low density and strength. Relatively
inexpensive; used for general-utility lumber.

spruce pine See eastern hemlock.

sprung Said of timber or other structural mem-
bers which have been bent by overloading.

sprung floor Same as resilient floor.

sprung molding A curved molding.

SPT Abbr. for "standard penetration test."

spud l.A sharp narrow bar or spade used for
removing gravel and roofing from a roof. 2. A
dowel which is in the foot of a doorpost. 3. A
short pipe which serves as a connection in a pip-
ing system.

spudding drill Same as churn drill.

spud vibrator A type of concrete vibrator used
to consolidate freshly placed concrete by insert-
ing it into the mass of concrete.

spun concrete Concrete compacted by cen-
trifugal action, e.g., in the manufacture of pipes.

spur l.An appendage to a supporting structure,
as a shore, prop, or buttress; a decorative
appendage of the base of a round column resting
on a square or polygonal plinth, set at the corners,
and taking the form of a grotesque, a tongue, or
leafwork. Also called a griffe. 2. A spere.

spur, 1

spur beam A horizontal timber, across the
thickness of a wall, which is fixed to a wall plate,
rafter, and ashlaring.

spur pile See batter pile.

spur shore A slanted timber holding a coffer-
dam around an excavation.

spur stone A stone post or block, set at the cor-
ners of archways, or the like, to protect the cor-
ners from damage by vehicles.

spur tenon Same as stub tenon.

spur wall A wall of relatively short length that
is at right angles to the main wall.

sq. Abbr. for "square."

sq.E&S Abbr. for "square edge and sound."

square 1. A measure of roofing materials; equals
100 sq ft (9.29 sq m). 2. Any piece of material
sawn or cut to be rectangular with equal dimen-
sions on all four sides. 3. A steel square for
checking angles.

square and flat A frame, without molding,
containing a flat panel; also see square-framed.

square and rabbet Same as annulet.

square billet A Norman molding consisting of
a series of projecting cubes, with spaces between
the cubes.

927

square bolt

square bolt A door bolt which moves in a cas-
ing; similar to a barrel bolt but has a square
rather than a circular cross section.

squared log A balk.

square dome Same as coved vault.

squared rubble Wall construction in which
squared stones of various sizes are combined in
patterns that make up courses as high as or
higher than the tallest stones.

squared splice See square splice.

square-edged lumber Lumber having the
edges sawn or planed, removing the wane to
form a 90° angle; also see square-sawn lumber.

square-edge door A door having vertical
edges that are perpendicular to the plane of its
faces.

square end The east end of a church having a
rectangular plan.

square-framed In joinery, framing having all
the angles of its stiles, rails, and mountings
square, without being molded.

square-headed Cut off at right angles above,
as an opening with upright parallel sides and a
straight horizontal lintel, as distinguished from
an opening that is arched.

square-headed window A window having a
straight horizontal lintel above it.

square joint See straight joint, 2 .

square mil A unit of area equal to a square hav-
ing sides equal to 0.001 in.; sometimes used to
express the cross-sectional area of an electric
conductor.

square miter An ordinary miter joint, where
the abutting edges meet at an angle of 45°.

square notch At the corner of a log house, a
joint formed by cutting away part of the upper
half of one end of a timber and placing this timber

at right angles to the end of another timber whose
lower half has also been partially removed. A
spike (or other fastener) through the overlapping
timbers is required to secure the joint.

square-rigger house A colonial New
England hip roof house with chimneys at both
gable ends, or on both sides of a central hall, or
centered between the front and back rooms.
Many such houses had a widow's walk and/or
cupola on the roof.

square roof A roof in which the rafters on
opposites sides of the roof ridge meet at an angle
of 90 degrees; each side of the ridge has a pitch of
45 degrees with respect to the vertical.

square-sawn lumber Sawn lumber having a
rectangular cross section, with or without wane.

square shoot A wood downspout.

square splice, squared splice A type of half-
lapped scarf joint, 1; may be reinforced with a
fishplate; esp. used to resist tension.

square notches

square splice

square staff In plastering, a narrow wooden strip

fixed as an angle bead at a salient corner of a room.
square-turned Said of ornamental balusters or

the like which are molded or decorated on all

four sides; not turned on a lathe.
square-turned baluster A baluster with

moldings cut on four sides without the use of a

lathe.

square up To plane a timber, piece of wood,
etc., so that its cross section is rectangular.

squaring Adjusting or constructing so that all
corners are rectangular. Also called squaring-off.

squatter's right The right of one who occu-
pies land without legal authority to acquire
ownership of it through long-continued occu-
pation. Also see adverse possession and pro-
scription.

squatting closet Same as Asiatic water closet.

squeezed joint A joint formed at the surface of
two pieces which have been coated with glue or
cement and squeezed together.

928

stack

squeeze-out The adhesive which is extruded
from a glue line as a result of the application of
pressure on the glued surfaces.

squib See electric squib.

squinch 1. Corbeling, often arcuate, built at
the upper corners of a structural bay to support
its tangent, smaller dome or drum. 2. A small
arch across the corner of a square room which
supports a superimposed mass; also called a
sconce.

squinch, 2

squinch arch See squinch, 2.

squint 1. A small opening, often obliquely cut,
in the wall of a church, generally so placed as to
afford a view of the high altar from the transept
or aisles. 2. A squint brick.

squint, 1

squint, 2

squint brick, squint quoin A building
stone or brick of special shape; used at an
oblique corner.

squint quoin See squint brick.

squint window See squint, 1.

SR Abbr. for "styrene rubber."

S/S Abbr. for stainless steel.

S»shape A standard, structural, hot-rolled
steel shape of a specified category, designated
by the prefix S placed before the size of the
member.

SST On drawings, abbr. for stainless steel.

St Symbol for strainer.

ST l.On drawings, abbr. for "steam." 2. On
drawings, abbr. for street.

stab To roughen a surface of a brick wall with
light blows of a pointed tool to provide a hold for
plasterwork.

stability The resistance of a structure or ele-
ment thereof to withstand sliding, overturning,
buckling, or collapsing.

stabilization The action of improving the sta-
bility of the sloped surface of a soil mass.

stabilizer A substance used to increase the sta-
bility of a solution or suspension, usually by pre-
venting precipitation.

stable A building, or portion thereof, for the
housing and feeding of horses, cattle, and other
domestic animals.

stable door Same as Dutch door.

stable equilibrium The condition of a struc-
ture in equilibrium; when a slight disturbance is
applied to the structure and then removed, the
structure returns to its equilibrium position.
Compare with unstable equilibrium.

stack l.Any vertical pipe, such as a soil pipe,
waste pipe, vent, or leader stack. 2. Such pipes,
collectively. 3. Any structure or part thereof

929

stacked ashlar

MAIN SOIL AND
WASTE VENT

stack, 1 : installation

which contains a flue or flues for the discharge of
gases. 4. A chimney stack. 5. In warm-air heat-
ing systems, a vertical supply duct. 6. A tier of
book shelves.
stacked ashlar Squared building stone that is
laid in a stacked bond pattern.

stack bond, stacked bond 1 . In brickwork, a
pattern bond; the facing brick is laid with all
vertical joints continuously aligned. The brick is
bonded to the backing by metal ties. 2. In stone
veneer masonry, a pattern in which units of a
single size are set with continuous vertical and
horizontal joints.

stack cap Same as vent cap.

stack effect See chimney effect.

stack partition Any partition which carries a
stack internally.

stack vent l.The extension (to the open air)
of a soil or waste stack above the highest hori-
zontal branch drain or fixture branch connected
to the stack. Also called a soil vent or waste
vent. 2. In built-up roofing systems, a vertical
outlet permitting water vapor, which is
entrapped within the insulation, to escape.

To roof vent
i.*~-Stock venl

!
I
I
I
I

_£•— Soil Stock
stack vent, 1

stack bond, 2

stack venting A method of venting a fixture
or fixtures through the soil stack or waste stack;
the fixtures must be grouped within a predeter-
mined distance from the stack so that individual
venting is not required.

staddle 1 . A rack or supporting framework
placed beneath a stack, such as a haystack. 2.
Any similar supporting framework.

staddle stone One of the stones which sup-
ports a staddle, 1; usually mushroom-shaped.

stadia rod, stadia A graduated rod used in
the determination of distance by observing the
intercept on the rod subtending a small known
angle at the point of observation; the angle
usually is defined by two fixed lines in the
reticle of a telescope (transit or telescopic
alidade).

stadium A sports arena, usually oval or horse-
shoe-shaped.

staff 1. Ornamental plastering, made in molds
and reinforced with fiber; usually nailed or wired
into place. 2. An exterior wall covering resem-
bling stucco, used on temporary buildings. 3. A
staff bead. 4. A piece used to close the joint

930

stain

between a wooden frame, as a window or door
frame, and the masonry in which it is set.

staff angle See angle staff.

staff bead 1. Same as angle bead, corner bead.
2. A backhand. 3. A brick molding.

Staffordshire blue A blue brick.

stage l.A floor area or platform for dramatic,

musical, or other types of performances. 2. Same

as staging.
Stage box A proscenium box.
stage door An exterior door leading to the

backstage of a theater, used primarily by theater

personnel.

stage equipment Equipment which is specifi-
cally fabricated for a theater stage to facilitate
the setting and striking of stage scenery.

stage grouting Grouting in a series of steps
rather than in one operation.

stagehouse In a theater, the part of the build-
ing on the stage side of the proscenium, includ-
ing the stage, wings, and storage area.

stage left The side of the stage to the left of an
actor as he faces the audience.

stage level The elevation of a stage.

stage lift A section of the stage floor of a legiti-
mate theater that can move upward or down-
ward; designed to carry scenery between the
stage storage areas, and/or for temporary use at
elevations above or below the stage level, for
special scenic effects.

stage peg, stage screw A coarse-threaded
hand screw, inserted into the stage floor of a the-
ater, to secure a brace for scenery.

stage pocket In the backstage of a theater, one
of several metal boxes, with hinged lids, which
are set into the wall or floor outside the acting
area; contains jacks into which electric cables
for stage lighting can be plugged.

stage rigging Collectively, the ropes, wires,
blocks, pulleys, pins, counterweights, winches,
and other pieces of stage equipment required for
the movement of scenery from overhead.

stage right The side of the stage to the right of
an actor as he faces the audience.

stage wagon Same as scenery wagon.

stage wall pocket A stage pocket set into a

wall.

staggered Descriptive of fasteners (such as nails,
rivets, or screws), joints, studs, etc., arranged in
two or more rows so that the beginning of each
row is offset from the adjacent one(s).

staggered course One of the courses of shin-
gles, tiles, etc., on roofing where the butts do not
form a horizontal line.

staggered partition Same as staggered-stud
partition.

staggered riveting Rivets set in a zigzag pat-
tern, so spaced that the rivets in one row are
opposite the centers of the spaces of the adjoin-
ing rows.

staggered-stud partition A partition using
wood studs which are not in a straight line, but
in two rows which are staggered; one row of
studs supports the lath on one side of the wall,
and the second row supports the lath on the
other; a fiberglass blanket may be woven be-
tween the staggered studs to improve the sound
insulation value of the wall.

staggered-stud partition

staging l.A temporary platform for workers
and the materials they use in building erection; a
scaffold. 2. A temporary platform for workers
which is supported on temporary timbering of a
trench.

stain 1. A discoloration in the surface of wood,
plastic, sealant, etc. 2. A colorant for enhancing
wood grain during finishing. 3. A stainer.

931

stained glass

stained glass A decorative glass that is given a
desired color, not by staining the glass, as the
name implies, but by any one of several tech-
niques. One method involves the application of
an enamel paint onto a plain or tinted glass sur-
face and firing it in a kiln. Another method fuses
various metal oxides with glass while it is in its
molten state; the resulting color, which has a
jewel-like quality, depends on the metal oxide
used. William Morris and his handycraftsmen in
a studio near London may be said to have
revived the modern art of making stained glass.
Louis Comfort Tiffany ( 1 848-1933 ) and John La
Farge (1835-1910), developed yet another tech-
nique for making stained glass called opalescent
glass, Favrile glass, or American glass, now often
referred to as Tiffany glass. It is characterized by
unusual combinations of colors and special
effects in transparency and opaqueness, creating
exaggerated color variations within the glass
itself; was much used in the late 1800s and early
1900s for decorative objects, and to highlight
architectural details.

stained-glass window A window whose glass
is colored.

stainer, coloring pigment, tinter A pig-
ment or dye which is used to impart color to
paints.

staining The application of a liquid dye solu-
tion to a porous surface to impart color.

staining power See tinting strength.

stainless steel A high-strength, tough steel
alloy; usually contains 4 to 25% chromium with
nickel as an additional alloying element; highly
resistant to corrosion and rust.

stair A series of steps (or flights of steps), con-
nected by landings, that permit passage

RISER

RUN

■* — *-

TREAD

STAIR CARRIAGE

between two or more levels or floors. For spe-
cific types, see box stair, bracketed stair, circu-
lar stair, cockle stair, cylindrical stair, dogleg
stair, double-entry stair, double-L stair, double-
return stair, double stair, fire stair, geometrical
stair, good-morning stair, halfpace stair, hang-
ing stair, helical stair, hollow-newel stair, inte-
rior stair, newel stair, open-newel stair, open
stair, quarterpace stair, quarter-turn stair,
reverse-flight stair, solid-newel stair, spiral stair,
straight-flight stair, straight-run stair, well stair.

stair bolt Same as handrail bolt.

stairbox Same as staircase, 2.

stair bracket A bracket, often decorative,
which is fixed to the face of an open string,
immediately under the return nosing of each stair
tread, to stiffen the tread.

stair: nomenclature

stair bracket

stairbuilder's truss Crossed beams which sup-
port a landing of a stair.

stair carriage Same as carriage, 1.

staircase 1. A flight of stairs, or a series of such
flights, including supports, handrails, and frame-
work. 2. The structure containing a flight of stairs.

stair chair-lift See chairlift.

stair clip A metal clip, or equivalent, used to
hold a stair carpet in place.

stair dormer A dormer of sufficient width to
accommodate the upper part of a staircase lead-
ing to an upper half-floor or attic.

stair flight See flight.

stair hall A room in a home, usually of some
pretentiousness, that is especially designed to
contain and display a stair.

stairhead The initial stair at the top of a flight

of stairs or staircase.
stair headroom The clear vertical height

measured from the nosing of a stair tread to any

overhead obstruction.

932

staking out

stair horse A carriage, 1.

stair landing See landing.

stair nosing See nosing.

stair platform An extended step or landing

which breaks a continuous run of stairs.
stair rail See rail, 1.
stair rise Same as rise, 1.
stair riser See riser, 1.
stair rod A metal rod used to hold a stair carpet

in place.
stair run Same as run, 2, 3.
stair shaft Same as stairwell.
stair shoe See shoe rail.
stair string, stair stringer See string.
stair tower 1 . A staircase. 2. A stair turret.
stair tread See tread.
stair trimmer See trimmer.
stair turret 1 . A building containing a winding

stair which usually fills it entirely. 2. A stair

enclosure which projects beyond the building

roof.
stair wall string See wall string.
stairway A staircase.

stairwell The vertical shaft which contains a
staircase.

stair windows Same as stepped windows.

stair wire A light stair rod.

stake 1 . A small anvil used for the working of
thin sheet metal, so called because it is sup-
ported by a sharp vertical prop which is
inserted in a hole in the workbench; the sheet-
metal worker may select one of a number of
different stakes, the particular shape depend-
ing on the task. 2. A stick of wood sharpened
at one end and set into the ground to act as a
boundary marker or to support or hold some-
thing.

stake-and-rider fence A rail fence assem-
bled without the use of post holes, as follows:
two stakes are crossed, forming a crotch near
their upper ends; a horizontal rail (called the
rider) is supported by the crotch, then this
assembly is bound together at the crotch; a
series of such assemblies is required to form the
fence, often with additional horizontal rails
below the rider.

stake-and-rider fence

stair turret

staking out The driving of stakes, 2 for batter

boards, thereby locating the corners of an exca-
vation. (See illustration p . 934.)

933

stalactite work

BATTER BOARD

STAKE

SAW KERF

PLUMB
BOB

'OUTSIDE LINE OF
FOUNDATION WALL

staking out

stalactite work See muqarnas.

mJwI Ifc

stalactite work

stale sewage Sewage that contains little or no

oxygen and is free from putrefaction.
stalk See cauliculus.

stall 1 . A fixed seat enclosed wholly or partially
at the back and sides. 2. (Brit.) In the theater, a
seat in the front division of the parquet (orches-
tra stalls).

stallboard A strong sill (and lumber framing) at
the base of a storefront window which supports it.

stalls, 1

stallboard light A pavement light adjacent to
a stallboard.

stallboard riser On a storefront, the vertical
surface between pavement level and the stall-
board.

stallriser Same as stallboard riser.

stamba, stambha In Hindu architecture and
derivatives, a freestanding column surmounted
by a large symbol.

stamped-metal ceiling See pressed-metal
ceiling.

stamping A process used to shape a piece of
sheet metal by means of a die and a punch in a
drop hammer.

stanchion l.A prop, upright bar, or piece of
timber giving support to a roof, a window, or the
like. 2. An upright bar, beam, or post, as of a
window, screen, railing, etc.

standard l.A document prepared by a recog-
nized standard-setting organization that pre-
scribes methods and materials for the safe use
and consistent performance of specific technolo-
gies; usually a procedure that has been devel-
oped by consensus of the interested parties. 2.
As used by governmental agencies, a document
which sets certain legally permissible limits. 3.
See measurement. 4. A document containing
mandatory requirements indicated by the word
shall.

standard absorption trench An absorp-
tion trench which is 12 to 36 in. (approx. 30 to
90 cm) in width, containing 12 in. (30 cm) of
clean coarse aggregate and a distribution pipe
which is covered with a minimum of 12 in. (30
cm) of earth cover.

934

standby power generator

standard air Air having a density of 0.075 lb
per cu ft (0.0012 gm per cu cm) which approxi-
mates air at 68°F (20.0°C) dry bulb and 50% rel-
ative humidity at a barometric pressure of 29.9
in. (76.0 cm) of mercury, or approximating dry
air at 70°F (21.1°C) at the same pressure.

standard atmosphere A pressure equivalent
to 14-7 lb per sq in. (1.01 X 10 6 dynes per sq cm).

standard atmospheric pressure The pres-
sure exerted by a standard atmosphere; also see
atmospheric pressure.

standard cubic foot of gas The amount of
gas that would occupy one cubic foot at a tem-
perature of 60°F, saturated with vapor, and under
a pressure equivalent to that of 30.0 inches of
mercury column.

standard curing Subjecting test specimens of
concrete to specified conditions of temperature
and moisture.

standard cylinder A solid, concrete cylinder
used to determine the compressive strength of
the concrete as well as its splitting tensile
strength; usually 12 in. (30.5 cm) long and 6 in.
(15.2 cm) in diameter.

standard dimensions ratio (SDR) The
ratio of the average specified outside diameter to
the minimum specified wall thickness of a pipe.

standard hook At the end of a steel rein-
forcing bar, a hook made in accordance with a
standard.

standard inside diameter dimension ratio
(SIDR) The ratio of the average specified
inside diameter to the minimum specified wall
thickness of a pipe.

Standard International units, SI units See
International System of Units.

standard knot In wood, any knot VAin. (3.81
cm) or less in diameter.

standard penetration resistance, Proctor
penetration resistance l.The unit load
required to maintain a constant rate of pene-
tration of a probe into a soil. 2. The unit load
required to produce a specified penetration
into a soil, at a specified rate of penetration;
for a Proctor needle, the specified penetration
is 2.5 in. (6.35 cm) and the penetration rate is
0.5 in. (1.27 cm) per second.

standard penetration test See penetra-
tion test.

standard pile Same as guide pile.

standard pipe size See iron pipe size.

standard pressure Same as standard atmo-
spheric pressure.

standard railing According to OSHA: a
vertical barrier at floor level erected along
exposed edges of a floor opening, wall opening,
platform, runway, or ramp to prevent falls of
persons.

standard sand Ottawa sand, accurately graded
to pass a 850-jim (US Standard No. 20) sieve
and to be retained on a 600-jim (US Standard
No. 30) sieve; used in testing cements.

standards of professional practice State-
ments of ethical principles promulgated by pro-
fessional societies to guide their members in the
conduct of professional practice.

standard source In illumination engineering,
a light source having a specified spectral distri-
bution, used as a standard for colorimetry.

standard source A, light source A A tung-
sten filament lamp operating at a color tempera-
ture of 285 6°K (2583 °C).

standard source B, light source B A light
source that approximates noon sunlight having a
correlated color temperature of approx. 4874°K
(4601°C).

standard source C, light source C Light
which approximates a combination of direct
sunlight and a clear sky having a correlated color
temperature of 6774°K (6501 °C).

standard special A special-shaped brick that
is in general use and may be available from
stock.

standard temperature and pressure A

temperature of 32°F (0°C) and a barometric
pressure of 29.9 in. (76.0 cm) of mercury.

standard tolerance An established tolerance
for a particular class of product.

standard wire gauge A wire gauge formerly
used in Great Britain and Canada; superseded by
metric wire diameters.

standby lighting Lighting designed to supply
illumination in the event of failure of the nor-
mal lighting system, so that normal activities in
the area may continue.

standby power generator A packaged unit
including a prime mover, electric generator, and

935

standing bevel

associated controls and equipment to provide
power if the normal source fails.

standing bevel A bevel which forms an obtuse
angle.

standing finish That part of the interior fit-
tings of a building which is permanent and fixed
in place, as distinguished from doors, movable
sashes, etc.

standing gutter A V-shaped gutter near the
lower end of a sloped roof; one side of the V is
formed by a long board, running parallel to the
eaves, whose broad side is approximately per-
pendicular to the sloping surface of the roof; the
roof itself acts as the other side of the V.

standing leaf An inactive leaf of a door, bolted
in a closed position.

standing panel A panel whose longer dimen-
sion is vertical.

standing room A space set aside for spectators
to stand, usually at the back of the orchestra sec-
tion of a theater.

standing seam In metal roofing, a type of seam
between adjacent sheets of material, made by
turning up the edges of two adjacent sheets and
then folding them over.

standing seam along the ridge of a roof

standing waste A type of device for the con-
trol of the outlet and overflow of a plumbing fix-
ture; an overflow pipe is inserted in the outlet at
the bottom of a fixture or tank, permitting water
to be retained at a desired level.

stand oil A polymerized vegetable oil, such as
linseed or tung oil, which has been heated
(without blowing) at a high temperature in
order to thicken it to the consistency of honey;
used as a medium in paints.

standpipe A pipe or tank used for the storage of
water, esp. for emergency use.

standpipe connection

standpipe system A system of standpipes,

pumps, Siamese connections, and piping, pro-
vided with an adequate supply of water and
equipment with hose outlets for fire fighting.

stand sheet See fixed light.

stanza A room or chamber within a building, as
the stanze of Raphael in the Vatican.

staple A U-shaped piece of metal or heavy wire,
with pointed ends, driven into a surface to
secure a sheet of material, hold a hasp, etc.

staple gun A tool for driving wire staples; esp.
used in construction for fastening materials such
as building paper, asphalt prepared roofing, and
the like.

staple hammer, stapling hammer A tool,
resembling and swung like a hammer, that drives
a staple when the face strikes a surface.

stapler 1. A staple gun. 2. A staple hammer.

stapling hammer See staple hammer.

star anchor Same as anchor, 10.

starch gum See dextrin.

star drill A long steel tool having a star-shaped
point, used for drilling holes in concrete,
masonry, and stone; it is handheld, the head
being struck repeatedly with a hammer to pro-
vide the drilling action.

star drill

936

static penetration test

star expansion bolt A type of expansion bolt

which has a shield of two semicircular parts that
are forced apart as the bolt is driven.

star molding A common Norman molding
whose surface is a succession of projecting star-
like shapes.

Star of David, Mogen David A six-pointed
star composed of two equilateral triangles, one
superimposed upside down on the other; a sym-
bol of Judaism.

star-ribbed vault Same as star vault.

starshake A number of heartshakes which
radiate from the center of a log in a star-like
pattern.

ROOF SHEATHING

starshake

starter 1 . A device used with a ballast to start an
electric-discharge lamp. 2. An electric con-
troller for starting an electric motor, for bringing
it up to normal speed, and for stopping it. 3. One
of a series of roofing shingles applied beneath
the first course of shingles, with a slight over-
hang at the eaves.

starter frame Shallow formwork which pro-
jects above floor level, for the location and sub-
sequent construction of a column or wall.

starter strip, starting strip The first course of
composition roofing material, applied along a
line adjacent to the eaves.

starter tile See eaves tile.

starting board In the construction of form-
work, the board at the foundation which is first
nailed in place.

starting course The first course of shingles
applied to roof sheathing, along a line adjacent
to the eaves.

starting newel The newel-post at the foot of a

stair.

starting step The lowest step in a flight of

stairs.

starting strip See starter strip.

starting course

start of construction See actual start of con-
struction.

star trap A type of trap in a theater stage
through which an actor, standing on a counter-
weighted platform, can make a sudden appear-
ance or disappearance.

star vault, stellar vault A vault whose rib
pattern suggests a star.

starved See hungry.

starved joint A poorly bonded glue joint
resulting from an insufficient quantity of glue in
the joint.

statement of probable construction cost
Cost forecasts prepared by the architect during
the schematic design, design development, and
construction documents phases of basic services
for the guidance of the owner.

static bending Bending under a constant load
or a very slowly applied load.

static deflection Same as residual deflection.

static fatigue Failure of a component as a
result of its sustaining a heavy, continuous load.

static head, pressure head The static pres-
sure of fluid expressed in terms of the height of a
column of the fluid which the pressure could
support.

static load Any load, as on a structure, which
does not change in magnitude or position with
time.

static modulus The ratio of stress to strain
under static conditions.

static penetration test A penetration test in

which penetration into the soil results from the
application of a steady force on a testing device.
Also see dynamic penetration test.

937

static pressure

static pressure 1. In an air distribution system,
the pressure which the fan must supply to over-
come the resistance to airflow through the sys-
tern ductwork and system components.
2. The pressure which a fluid exerts on a surface
at rest with respect to it. 3. At a point, the
atmospheric pressure in the absence of sound
waves; usually expressed in pascals.

statics That branch of the science of mechanics
concerned with forces acting on bodies in equi-
librium.

static test On windows and curtain walls: 1. A
structural test, subjecting a test unit to a pressure
differential equivalent to the maximum
expected wind pressure. 2. A water test simulat-
ing the flow of water down over the test unit
during a hurricane.

static Young's modulus The value of Young's
modulus derived from static measurements of
stress-strain relationships, rather than from
dynamic measurements.

station 1. A definite point on the earth whose
location has been determined by surveying
methods. 2. A point on a survey traverse over
which an instrument is placed. 3. On a survey
traverse, a length of 100 ft measured on a given
line — broken, straight, or curved.

stationary hopper A container used to
receive and store temporarily freshly mixed
concrete.

stationary window A window or area of a
window that does not open; glazed directly in a
fixed frame.

station roof 1 . A roof which is shaped like an
umbrella, supported by a single post in the cen-
ter; also called an umbrella roof. 2. A long roof
supported by a single row of posts and from can-
tilevers to one or both sides, as on a railway sta-
tion platform.

statute of frauds A rule that certain kinds of
contracts are unenforceable unless signed and in
writing or unless there is a written memorandum
of their terms signed by the party to be charged.
In most states contracts for the sale of real prop-
erty or for leases of over a specified duration
must be in writing to be enforceable.

statute of limitations A statute specifying the
period of time within which legal action must be

brought for alleged damage or injury. The
lengths of the periods vary from state to state
and depend upon the type of legal action. The
period commences to run under some statutes of
limitations upon the accrual of a legal claim, but
in others only upon the time of discovery of the
act resulting in the alleged damage or injury.
statutory bond A bond, the form or content
of which is prescribed by statute.

St. Augustine house See Saint Augustine

house.
staunchion Same as stanchion.

stave 1 . One of a number of narrow boards used
to build up a curved surface. 2. A rung of a lad-
der. 3. In formwork for an excavation, one of
many vertical members which form a curved sur-
face (in plan).

stave church A Scandinavian wooden church
with vertical planks forming the walls.

stave church

stave core See continuous block core.
staved lumber core Same as coreboard.

stay 1 . Anything that stiffens or helps to main-
tain a frame or other structure, as a strut or
brace. 2. See casement stay, peg stay.

stay bar Same as casement stay.

938

steam trap

stay bolt

end.

A long metal rod having a threaded

stay bolt

stay plate See batten plate.

stay rod A tie rod which prevents spreading of
the parts to which it is connected.

stay rope A rope that serves as a guy.

STC Abbr. for sound transmission class.

STD On drawings, abbr. for "standard."

Std. M Abbr. for "standard matched."

steam bending The process of steaming a
piece of wood in order to shape it into a desired
form.

steam blow A blister, 1.

Steamboat Gothic A richly ornamental
mode of Carpenter Gothic architecture, making
elaborate and imaginative use of gingerbread;
primarily found in the middle to the latter half
of the 19th century, suggestive of the ornate and
flamboyant decorations on steamboats on the
Ohio and Mississippi Rivers.

steam boiler and machinery insurance
Special insurance covering steam boilers,
other pressure vessels, and related equipment
and machinery; covers damage or injury to
property resulting from explosion of steam
boilers which is not covered by extended cov-
erage perils.

steam box, curing kiln An enclosure for the
steam curing of concrete products.

steam cleaner A machine that generates a
high-pressure jet of steam which can be di-
rected through a nozzle to scour dirt or grease
from a surface; may use detergents or other
chemicals.

steam curing The curing of concrete or mortar
in water vapor at an elevated temperature, at
either atmospheric or high pressure.

steam-curing cycle l.The time interval
between the start of the temperature-rise
period and the end of the soaking period or the
cooling-off period. 2. A schedule of the time
and temperature of the periods which make up
the cycle.

steam-curing room, steam kiln A chamber
for steam curing concrete products at atmo-
spheric pressure.

steam curtain An apparatus consisting of per-
forated pipes, located at the proscenium of a the-
ater, from which steam escapes; used to block or
partially obscure a view of the stage.

steam grid humidifier, steam jet humidi-
fier A humidifier in an air duct in which
steam is introduced into the airstream through a
series of perforated pipes.

steam heating system A system in which
heat is transferred from a boiler or other source
of heat to the radiators by means of steam at,
above, or below atmospheric pressure.

steam humidifier A humidifier in which
steam is injected directly into an airstream.

steam jet humidifier See steam grid humid-
ifier.

steam kiln See steam-curing room.

steam pipe Any pipe in which steam is
conveyed.

steam shovel A power-shovel operated by
steam which is generated in its own boiler.

steam table A table, or a section of a counter
in a cafeteria, having openings set in the top
in which are fitted containers for cooked food;
the containers are kept warm by steam, hot
air, or hot water which circulates beneath
them.

steam trap A device for allowing the passage of
condensate, or air and condensate, and prevent-
ing the passage of steam.

939

steatite

steatite An industrial grade of talc of high
purity; block steatite which meets a specified
degree of purity is designated as soapstone.

steel A malleable alloy of iron and carbon
produced by melting and refining pig iron
and/or scrap steel; graded according to the
carbon content (in a range from 0.02 to
1.7%); other elements, such as manganese and
silicon, may be included to provide special
properties. Also see high steel and tempered
steel.

steel-cage construction Same as skeleton
construction.

steel casement A casement; usually made
from hot-rolled steel sections; often classified as
a residence, intermediate, or heavy-intermediate
steel casement.

steel concrete See reinforced concrete.

steel decking See decking, 2 and metal floor
decking.

steel-frame construction Construction in

which the structural supporting elements con-
sist of combinations of steel beams, steel girders,
and steel columns, joined together at their
intersections.

steel H-pile See H-pile.

steel joist In a building, any steel structural
member that is composed of hot-rolled or cold-
formed solid or open-web sections of steel or
welded bars, strip- or sheet-steel members, or
slotted, expanded, or otherwise deformed rolled
sections of steel.

steel lathing See metal lath.

steel measuring tape A tape measure.

steel pipe A pipe manufactured in any of a
large number of steel alloys, either extruded
(seamless) or welded (with in a seam). Its wall
thickness ranges from Schedule 10 (lightest) to
Schedule 160 (heaviest).

steel sheet In steel construction work, a cold-
formed sheet of metal which is shaped as a struc-
tural member to carry loads (live or dead) in
lightweight concrete roof construction.

steel square A steel carpenter's square.

steel stud An upright post or support (i.e., a
stud) fabricated of sheet steel; usually one of
many in constructing a stud partition.

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one type of steel square

steel stud anchor A metal piece or clip
attached to the inside of a doorframe to secure
the frame to a steel stud.

steel tape See tape measure.

steel troweling The use of a trowel or a trow-
eling machine in the final stages of concrete fin-
ishing operations to impart a relatively smooth
surface to a concrete floor or other unformed
concrete surface.

steel 'wool A matted mass of long, fine, steel
fibers; esp. used for cleaning and polishing
surfaces.

steening The brick or stone lining, often laid
dry, of a cesspool, cistern, or well.

steep asphalt Roofing asphalt having a high
softening point; esp. applied on roofs that are
steep.

steeple A tall ornamental structure; a tower,
composed of a series of stories diminishing in
size, and topped by a small pyramid, spire, or
cupola.

steeple house A term used by some religious
faiths for a church.

steining Same as steening.

940

stepped-back chimney

stele, stela l.In classical architecture and
derivatives, an upright stone, usually a slab,
marking a grave. 2. A wall area set aside as a
memorial.

finial to a Greek stele

stellar vault See star vault,
stem The web, 1 of a structural tee.

stemming A suitable inert incombustible
material or device used to confine or separate
explosives in a drill hole, or to cover explosives
in mudcapping.

stench trap 1 . A trap, 1 . 2. A flap trap in a cel-
lar drain, preventing sewer air from entering the
building.

step A stair unit which consists of one tread and
one riser.

step bracket Same as stair bracket.

step brazing A method of brazing in which
successive joints on a part are joined with filler
metals of successively lower brazing tempera-
tures, so that the joints previously brazed are not
disturbed.

step-down ceiling diffuser A ceiling dif-
fuser which projects below the plane of the fin-
ished ceiling.

step flashing Same as stepped flashing.

step gable See corbie gable.

step iron A U-shaped heavy metal loop which
is set into masonry work; usually one in a series
to provide convenient steps for climbing up or
down a wall, chimney, etc.

step joint 1. A notched joint for two structural
timbers making an angle with each other, as a

tie beam and rafter. 2. A joint between the ends
of two rails of different height and/or section.

step-kiln See progressive kiln.

stepladder A ladder having flat steps, or treads,
in place of rungs; usually provided with a sup-
porting frame to steady it.

step log Same as notch-log ladder.

stepped arch An arch in which the voussoirs
are cut horizontally and/or vertically so they fit
in with the masonry courses above and below,
forming a series of steps.

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stepped arch

stepped-back chimney An exterior brick
chimney, rectangular in cross section, suffi-
ciently wide at the level of the hearth to enclose
a large fireplace on the interior, and then of
decreasing width, in number of steps, with
increasing chimney height.

stepped-back chimney

941

stepped column

stepped column A column whose cross sec-
tion changes abruptly at several points along its
length.

stepped flashing A metal flashing used at
the intersection of a wall and a sloping roof;
the upper edge of the vertical part of the flash-
ing steps down, following the general inclina-
tion of the roof; the horizontal edges are
fastened to raggle cut in the brickwork of
masonry walls.

< flashing;^

BASE
FLASHING

SOLDERED S|j
LAP SEAM

stepped flashing

stepped floor A floor on the stage of an audi-
torium which rises in steps, as contrasted to a
raked or ramped floor.

stepped footing A footing consisting of a
series of concrete prisms of progressively smaller
lateral dimensions, one above the other, to
distribute the load of a wall or column to the
subgrade.

stepped foundation A foundation cut in a
series of steps in a sloping bearing stratum, to
prevent sliding when subject to the bearing load.

stepped gable Same as corbie gable.
stepped ramp, ramped steps A series of

ramps which are interconnected by steps.
stepped string Same as open string.
stepped voussoir A voussoir which is squared

along its upper surfaces so that it fits horizontal

courses of masonry units.
stepped windows A series of windows set in

an exterior wall adjacent to a staircase, arranged

in a stepped pattern that generally follows the

ascent of the steps.

stepping 1. Softwood lumber suitable for steps;
usually pine or fir. 2. A step-plank. 3. In con-
crete step construction, benching, 1, 2. 4. In sur-
veying, chaining in a series of steps, over a
sloping surface, where the chains are always hor-
izontal.

stepping off Laying off, exactly, the required
length of a rafter by the use of a framing square.

steppingstone A flat stone set in level with
the earth, or set in a pond or stream, to provide
a footpath.

step-plank Hardwood lumber, usually about VA
to 2 in. (3.2 to 5.1 cm) thick, esp. used as step-
ping.

step pyramid An early type of pyramid having
a stepped superstructure.

step pyramid

step soldering A method of soldering in which
successive joints on a part are joined with solders
of successively lower soldering temperatures, so
that joints previously soldered are not disturbed.

step turner A tool, made of hardwood, used to
shape a stepped flashing.

stereobate The substructure, foundation, or
solid platform upon which a building is erected.
In a columnar building, it includes the stylobate
(the uppermost step or platform of the founda-
tion upon which the columns stand).

stereochromy A method of painting in which
water glass serves as the connecting medium
between the color and its substratum.

stereotomy The art of cutting solids, e.g.
stone, into certain figures or shapes.

steyre Old English term for grees.

STG On drawings, abbr. for "storage."

stiacciato In very low relief, as if a bas-relief
had been pressed flatter.

stick l.Any long slender piece of wood. 2. A
shaped piece of wood, as a stake.

stick-and-rag work See fibrous plaster.

942

stiffness factor

sticker 1 . A narrow rectangular strip of wood
used to separate pieces of lumber in piles. 2. A
piece from which molding is cut. 3. A sticker
machine.

sticker machine, sticker molder A machine
for shaping moldings.

sticking l.The shaping of molding. 2. The
cementing together of pieces of broken or sepa-
rated stone, or the like.

sticking board A frame used to position a
piece of wood while a molding is being cut in it.

sticks-and-clay chimney, sticks-and-mud
chimney, stick chimney Same as clay-
and-sticks chimney.

Stick style An eclectic style of domestic archi-
tecture in the United States primarily from about
1860 to 1890, mainly of wood-frame construc-
tion; usually asymmetric in both plan and section;
has applied ornamentation in the form of wood
boards on the exterior surfaces that is intended to
express the inner structure of the building. Build-
ings in this style usually include some of the fol-
lowing characteristics: a facade of clapboard or
board-and-batten siding with structural framing
materials used as exterior ornamentation or wood
boards prominently applied in patterns on wall
surfaces; prominent structural corner posts; spa-
cious porches, decorated in wood with simple
diagonal braces or brackets; a steeply pitched

Stick style

gable roof, often with intersecting gables and/or
cross gables; eaves with a significant overhang,
often supported by large diagonal brackets;
exposed roof trusses and rafters; corbeled chim-
neys.

stickwork Wood boards applied in patterns in
the horizontal, vertical, and diagonal directions,
usually over the exterior wood cladding of a
house.

sticky cement Cement having reduced ability
to flow freely as a result of pack set, or ware-
house set.

stiffback Same as strongback.

stiffened compression element A struc-
tural element, subject to compressive forces,
that has been reinforced or stiffened, along a line
perpendicular to its weak axis of bending, in
order to provide additional strength against
buckling.

stiffened expanded metal Same as self-cen-
tering lath or rib lath.

stiffened seated-beam connection A

seated-beam connection that has a vertical ele-
ment directly below the horizontal component
of the seat in order to help support the load
above.
stiffener 1 . A secondary member, usually an
angle iron or channel, 1, attached to a plate or
sheet to increase its stiffness and to prevent buck-
ling. 2. In a hollow-metal door, the internal rein-
forcement for door panels; usually channel iron.

stiffening angle An angle iron connected to
the web of a girder to stiffen it against buckling.

stiff frame See rigid frame.

stiff leaf (Brit.) In medieval ornament and
derivatives, a formalized leaf shape.

stiff-leg derrick A derrick comprised of a mast

and boom, with two (relatively short) sloping

fixed legs supporting the mast.
stiff-mud brick Brick produced by extruding a

stiff, but plastic, clay (12 to 15% moisture)

through a die.

stiffness The ratio of the force applied to a
structure (or a structural element) to the corre-
sponding displacement.

stiffness factor Of a member, the ratio of
the moment of inertia of the cross section to its
length.

943

stilb

stilb A unit of luminance equal to 1 candela
per sq cm. Abbr. sb. The use of this term is dep-
recated.

S-tile A roof tile S-shaped in profile.

stile 1 . One of the upright structural members of
a frame, as at the outer edge of a door or a win-
dow sash. 2. A set of steps, or a framework of bars
and steps, for crossing over a fence or wall.

UPPER
STILE

LOWER
STILE

window stile, 1

V /

\ (

)

\ >

/ \

door stile, 1

Stile Liberty The Italian version of Art Nou-
veau, so named after the firm of Liberty and Co.
in London.

stile plate Same as push plate.

stillicidium In Doric buildings, dripping eaves

in which the roof terminates.
stillroom A room connected with the kitchen,

where coffee, tea, and the like are stored and

prepared for use.
Stillson wrench A hand tool especially used

for grasping a pipe.
stilt l.A structural area or element lifting

another such above its regular position. 2. A

post which raises a structure above ground or

water level. 3. A member placed above or below

another vertical member for additional height.

4. See stilted arch. 5. Of a door frame: see base

anchor. 6. A brace in bridging.
stilted arch An arch whose curve begins above

the impost line.

stilted arch

stilted vault A vault whose curve begins above
the line of the imposts.

stipple l.To make dots, points, etc., on a sur-
face (as a painted or freshly plastered surface), to
achieve a decorative effect. 2. A stippler.

stippled finish A dotted or a pebbly-textured
finish on a surface coat of paint, plaster,

944

stone

porcelain enamel, etc.; produced by striking
the unhardened coat with the bristles of a stip-
pling brush.

stippler 1. A broad flat-based brush having stiff
bristles for producing a texture on a surface such
as soft plaster or paint. 2. Any tool (as a rubber
sponge or a textured or tufted roller) used to cre-
ate a stippled surface.

stippling Dotted or pebbly-textured finish of
any kind.

stipulated sum agreement A contract in
which a specific amount is set forth as the total
payment for performance of the contract.

stirrup l.Same as hanger. 2. A bent rod, usu-
ally U-shaped or W-shaped; used in reinforced
brick or concrete construction. 3. A reinforcing
device to resist shear and diagonal tension
stresses in a beam. 4. A metal seat, attached to a
wall beam or post or hung from a girder, to
receive and support a beam or joist.

r — "■"■■'
WSM

• •

i -J;

•■ ■■■■■•" —

stirrup, 2

girder

StlRRUP

stirrup, 4

stirrup strap Same as stirrup, 4.

stitch nailing A method of nailing two pieces
of wood together by driving nails through each

of the two exposed sides so they cross each other
at right angles.

stitch rivet One of a number of rivets placed
at intervals between two component parts to
hold them together and to provide lateral
stiffness.

stitch welding The joining of two or more
parts by the use of intermittent welds.

STK On drawings, abbr. for "stock."

STL On drawings, abbr. for steel.

stoa A portico, usually detached, often of con-
siderable extent, providing a sheltered prome-
nade or meeting place.

stob A small post, as one of the uprights in
fencing.

stock 1. Lumber, panels, doors, windows, etc.,
commonly used and readily available from sup-
pliers. 2. The principal supporting or holding
part; the part in which other parts are inserted,
as the body of a tool. 3. A tool, used in cutting
threads for pipes or bolts, which holds the dies.

stockade A defensive barrier; logs or timbers
driven into the ground to form an enclosure.

stock brick In any geographical area, the type
of brick that is most commonly available.

stock brush In plastering, a brush for applying
water to dampen a base coat which is too dry
(before applying the finish coat) or to a finish
coat during troweling.

stockhouse set Same as warehouse set.

stock lock Same as box lock.

stock lumber Lumber which has been cut
to standard sizes and is readily available from a
supplier.

stock millwork Millwork manufactured in
standard sizes, patterns, and layouts, and readily
available from a supplier.

stock size A size which is normally available
from warehouse supplies.

stoker A mechanical device for feeding solid
fuel into a furnace.

stone Any type of rock that has been selected or
processed by cutting, shaping, or sizing for use in
building construction or for decorative purposes;
see brownstone, cobblestone, dimension stone,
fieldstone, flagstone, freestone, granite, lime-
stone, marble, pudding stone, rib vault, rusti-
cated stone, sandstone, soapstone.

945

stone bolt

stone bolt In masonry construction, a bolt
which is fixed in mortar for supporting a
member.

stone cabin A small house built of stone, typi-
fied by homes built by German-speaking
colonists in Pennsylvania; usually characterized
by a roof having a very steep pitch, thick stone
walls, and wooden casement windows with solid
shutters.

stone chip A small, angular fragment of stone
containing no dust.

stone drain Same as French drain.

stone dust Pulverized stone used for walks,
either mixed with earth and compacted or
mixed with gravel to fill the spaces between
irregular stones and produce a stable surface.

stone-ender, stone-ender house A late

17th-century house having post-and-girt fram-
ing; basically, a one-room medieval-style cottage
of the type described under American Colonial
architecture; found primarily in Rhode Island;
its most significant feature was a massive end
wall built of stone that incorporated a very large
fireplace chimney; an impressive chimney cap;
small casement windows containing panes of
glass set diagonally in lead cames; a battened
door at the entry, which opened into a small
room called the porch.

stone facing A relatively thin stone veneer
used as the exterior surface of a curtain wall, 2;
for example, the headquarters of the United
Nations has a stone facing of marble.

stone-filled sheet asphalt Asphalt concrete
in which most of the mineral aggregate passes
through a 2.00-mm (No. 10) sieve and conforms
to the requirements for sheet asphalt; ordinarily
confined to surface course construction.

Stonehenge A megalithic, prehistoric monu-
ment near Salisbury, England, in Wiltshire;
the most imposing megalithic monument in
existence.

stone lantern An outdoor lantern, usually
Japanese, used as a permanent garden ornament.

stone masonry Masonry composed of field,
quarried, or cast stone units bonded by mortar.

stone medallion A term occasionally used for
date stone.

stone sand Sand manufactured from stone.

stone-setter's adjustable multiple-point sus-
pension scaffold A swinging-type scaffold
having a platform supported by hangers suspended
at four points so as to permit the raising or lower-
ing of the platform to the desired working position
by the use of hoisting machines.

stone slate Thin-bedded stone slabbing or flag-
ging, irregular in size and shape, usually lime-
stone or sandstone; used as rough shingling on a
roof; separates along its bedding, unlike true
slate, which is a metamorphic rock that splits
along its cleavage.

stoneware, earthenware A hard, vitrified
ceramic ware, usually salt-glazed and treated in a
kiln at a high temperature; the vitrified body is
waterproof, frostproof, and well-suited for use on
the exterior of buildings.

stonework 1. Masonry construction in stone.
2. Preparation or setting of stone for building or
paving.

stool l.The flat piece upon which a window
shuts down, corresponding to the sill of a door.
2. A narrow shelf fitted across the lower part of
the inside of a window opening; butts against the
sill. 3. A window stool. 4. Same as packing
piece. 5. A framed support.

stoop A platform or small porch, usually up sev-
eral steps, at the entrance to a house.

stoop

stoothing (colloq.) Studding, lath and plaster,
common grounds, etc.

stop 1 . The molding or trim on the inside face of
a door or window frame against which the door
or window closes; a bead, 2. 2. The projecting
boss or other ornament against which the termi-
nation of a molding abuts. 3. A button, or the

946

storage capacity factor

like, which serves to lock a latch bolt in the

position in which it is set.
stop-and-check valve Same as nonreturn

valve,
stop-and-waste cock A stopcock having a

drain in the valve, used in a water piping system;

when the stopcock is turned so that the water

supply is shut off, the drain in the valve opens,

thereby draining off the water downstream from

the stopcock to a waste.

stop-and-waste cock

stop bead See bead, 9.

stop chain In a theater stagehouse, a chain
between the gridiron and the top of the fire cur-
tain; used as a limiting device to restrain the cur-
tain when it reaches the stage floor.

stop chamfer, stopped chamfer A chamfer
which curves or angles, becoming narrower until
it meets the arris.

stopcock A valve to shut off flow of water or
gas in a branch of the building distribution
network.

stope An excavation in the earth in a series of
benches or tables.

stop end, stopped end l.The closed end of
gutter or ridge capping. 2. The squared-off, fin-
ished end of a wall.

stop molding A solid or struck molding which
is terminated short of the end of the member
into which it is cut.

stopoff A material used to limit the spread of
solder or brazing filler metal on the surfaces adj a-
cent to the joint.

stopped chamfer See stop chamfer.

stopped dado A dado, 3 which does not cut
across the full width of the piece of wood in
which it is set.

stopped dado

stopped end See stop end.

stopped flute In classical architecture and
derivatives, a flute terminated, usually about
two-thirds of the way down a column or pilaster.
Below this, the shaft may be smooth or faceted,
or the fluting may be incised partway, leaving a
flat surface sunk between fillets. A cabled flute is
sometimes called "stopped."

stopped mortise See blind mortise.

stopper, stopping A compound, such as putty,
used to fill holes in wood, metal, etc.

stopping Same as stopper.

stopping knife A putty knife.

stop screw A wood screw used to fasten a bead,
2 to a window frame.

stop stone In a pair of gates, a stone (in the
ground) against which the meeting stiles close.

stop valve A valve in a piping distribution net-
work which is used to shut off a line.

stopwork A mechanism on a lock which fixes
the spring bolt in the shot-out position so that it
cannot be operated by a key (or the handle)
from the outside, providing additional security;
can be set by a sliding button or push button.

storage capacity factor In a water heater, the
ratio of the volume of the storage tank to the
maximum volume of hot water probably used in
a one hour period.

947

storage cistern

storage cistern A cistern for storing water.

storage heating See thermal storage.

storage hopper See stationary hopper.

storage life, shelf life The time period for
which a material (such as a packaged adhesive or
sealant) can be stored, under specified tempera-
ture conditions, and remain suitable for use.

storage tank A container or vessel which
receives water from a source of supply and holds
it while awaiting distribution to the points of
consumption; a storage cistern.

storage-type water heater A water heater
composed of a horizontal or vertical storage
tank, a source of heat (such as an electric
heating coil or heat exchanger), and various
accessories for the control, safe operation, and
maintenance of the heater.

Hewing fluid in

storage-type water heater

store 1. A place where goods are kept for sale; a
shop. 2. A place where goods or materials are
accumulated and kept for future use.

store door handle Part of a door lock, a heavy
door pull, usually fixed to a surface-mounted
plate; provided with a thumbpiece which oper-
ates the latch trip.

store door latch A door latch which is oper-
ated by a thumb lever that moves the spring
bolt.

storefront, shop front The front of a store or
shop at street level, usually having one or more
windows for the display of goods or wares.

storefront sash An assembly of light metal
members which form a continuous frame for a
fixed-glass storefront.

storey See story.

storey rod See story rod.

storm anchor In roofing, a corrosion-resis-
tant metal fastener having a flat base; the

shank fastens the concealed lower corner of
each shingle to the exposed edge of the adja-
cent shingle.

storm cellar A cellar used for shelter against
violent storms such as cyclones, tornadoes, or
hurricanes.

storm clip In glazing, a clip on the exterior of
a glazing bar; prevents the pane from moving
outward.

storm door, weather door An auxiliary door
installed exterior to, and in the same doorframe
as, an entrance door to a house, to provide added
protection against cold and air infiltration; fre-
quently includes glass paneling.

storm drain A drain used for conveying rain-
water, subsurface water, condensate, cooling
water, or other similar discharges, but not sewage
or industrial waste, to a point of disposal.

storm lobby Same as storm porch.

storm porch An enclosed porch, or portion
thereof, protecting the entrance to a house from
the weather. Often erected only during the win-
ter months.

stormproof window A window designed to
resist wind, hail, snow, and rain in a storm or
hurricane.

storm sash See storm window.

storm sewage The sewage flowing in com-
bined sewers or storm sewers, resulting from
rainfall.

storm sewer A sewer used for conveying rain-
water or other similar discharges, but not sewage
or industrial waste, to a point of disposal.

storm- sewer system A sewer system consist-
ing only of sewers carrying rainwater, street
wash, cooling water, and similar discharges, but
excluding sewage and industrial waste.

storm sheet A sheet of roofing material having
one edge curved downward at the eaves to pro-
vide protection against rain.

storm water Water flowing on the surface of
the ground, resulting from heavy rainfall.

storm water channel A conduit for carrying
away surface water, subsurface water, or storm
water.

storm-water conductor In a roof drainage
system, a pipe (located within a building) that
carries off the drainage; if the pipe is attached to

948

straight-joint tile

the outside of the building, it is called a down-
spout or rainwater leader.

storm window, storm sash An extra win-
dow, usually placed on the outside of an existing
window as additional protection against severe
weather.

story (Brit, storey) l.The space in a building
between floor levels, or between a floor and a
roof above. In some codes and ordinances a
basement is considered as a story; generally a
cellar is not. 2. A major architectural division
even where no floor exists, as a tier or a row of
windows.

story-and-a-half The designation for a house
(or building) in which the ceilings of the sec-
ond-story rooms at the eaves are comparatively
low.

story drift The total lateral displacement that
occurs in a single story of a multistory building.

story height The vertical distance from the
finish floor on one level to the finish floor on the
level above.

story post One of several upright posts that
support a beam on which a floor rests.

story rod, height board, story pole A

wood rod equal in length to the distance
between two floors; may be divided into equal
parts, each equal to the height of a step for use in
stair construction. Also see gauge rod.

stoup A basin for holy water, sometimes free-
standing but more often affixed to or carved out
of a wall or pillar near the entrance of a church.

stovepipe A metal pipe for conducting smoke,
gases, etc., from a stove to a chimney flue.

stove room A term once applied to any room
heated by a stove.

stoving See baking.

St. Petersburg standard See Petrograd
standard.

Stpg Abbr. for "stepping."

Str. Abbr. for "structural."

STR. Abbr. for strike.

straddle pole In a saddle scaffold, the sloping
pole laid on the roof's surface.

straddle scaffold Same as saddle scaffold.

straight arch A brick arch whose soffit (i.e.,
lower face) is horizontal; the brick joints on each
side of its midpoint slant downward toward the

centerline; also called a Dutch arch, flat arch,
French arch, or jack arch.

straightedge, rod 1. A rigid, straight piece of
wood or metal used to strike off a concrete,
mortared, or plastered surface; a screed, 2. 2. A
long piece of seasoned, planed wood having
straight, parallel edges; used in construction to
lay out straight lines and to align framing.

straight-edge gable Same as straight- line
gable.

straight flight, straight stair A stair extend-
ing in one direction only, with no turns or
winders.

straight-grained 1. Descriptive of wood in
which the grain is more or less parallel to the
sawn edges. 2. Descriptive of quarter-sawn lum-
ber in which the grain appears as straight lines.

straight jacket A stiff timber which is fixed to
a wall so as to increase its rigidity and to rein-
force it.

straight joint 1 . In a wood floor, a continuous
joint formed by the ends of parallel boards; the
joint is perpendicular to the length of the boards.
2. In carpentry, a joint between two timbers which
are laid edge to edge without a tongue and groove,
dowels, or overlap to bind them; also called a
square joint. 3. A continuous vertical straight-line
joint formed by the ends of masonry units.

straight joint, 2

straight-joint tile A tile designed to be laid in
single-lap fashion so that the edges in successive
courses run in a straight line from the eave to the
ridge.

949

straight-line edger

straight-line edger, straight-line ripsaw A

mechanically fed saw used to straighten the
edges of veneer and lumber.

straight-line gable A term descriptive of a
parapeted end gable, the face of which rises
above the roof line; the edge of the parapet
forms a straight line at a steep pitch with respect
to the horizontal; especially found in Dutch
Colonial architecture and Jacobethan architec-
ture; occasionally called a straight-edge gable.

straight-line theory In the analysis of rein-
forced concrete members, theory based on the
assumption that stresses and strains in a member
under flexure vary in proportion to the distance
from the neutral axis.

straight lock A lock which is designed to be
fixed on the face of a door, requiring no prepara-
tion other than the cutting of a keyhole.

straight nailing Same as face nailing.

straight-peen hammer A hammer having a
blunt chisel-shaped peen whose edge is parallel
to the handle.

straight-run stair Same as straight-flight stair.

straight stair See straight flight.

straight tee A tee having all openings of the

same size.

straight tee

straight tongue A tongue along one edge of a

board.
straight tread Same as flier.
strain A change in the form or shape of a body

or material which is subjected to an external

force.
strain energy The work which is done in

deforming a body.
strainer A device for withholding foreign mat-
ter from a flowing liquid or gas; a sieve.
strainer arch An arch placed between two

walls to prevent them from leaning toward each

other.
strainer beam Same as straining beam.

strain gauge A very fine wire or thin foil
which exhibits a change in resistance propor-
tional to the mechanical strain imposed on it;
usually mounted on or bonded to some type of
carrier material or wound on a jig or fixture; used
in the experimental determination of stresses.

strain hardening The hardening of a metal
produced by cold working it.

straining arch An arch used as a strut, as in a
flying buttress.

straining beam, straining piece, strutting
piece In a truss, a horizontal strut above the
tie beam or above a line joining the feet of the
rafters, commonly between the joists at
midspan; esp. in a queen post truss, the strut
between the upper ends of the two queen posts.

straining piece l.Same as straining beam. 2.
Any member which is fixed between opposing
struts to take their thrusts.

straining sill In a timber roof, a straining beam
which is placed on the upper surface of the tie
beam of a roof truss, between posts, to resist the
inward thrust from struts.

strake 1 . On the siding of a house, a run of clap-
board. 2. In a tall steel chimney, a row of steel
plates.

strand l.A number of individual steel wires
twisted together. 2. A number of individual steel
wires laid together (not twisted). 3. In pre-
stressed concrete, a type of prestressing tendon.

stranded wire A group of small wires which is
used as a single wire.

strand grip In prestressed concrete construction,
a device used to anchor a prestressing tendon.

S-trap AnS-shaped trap, 1.

S-trap

strap l.A metal plate placed across the junc-
tion of two or more timbers to which it is bolted
or screwed. 2. See tie beam, 1. 3. See pipe strap.

4. A metal component designed to join a truss
and wall plate to a wall.

950

straw bale house

strap anchor Same as strap, 1.

strap bolt 1. Same as lug bolt. 2. A bolt having

the middle part of its shank flattened, so that it

can be bent in a U-shape.
strap footing, strip footing A continuous

foundation in which all loads occur in a straight

line.
straphanger A hanger, 1 in the form of a strap.

Bolt, lock nut,
and washers

Pipe

straphanger

strap hinge A surface-mounted hinge with
long flaps of metal on each side, by which it is
secured to a door and adjacent post or wall.

strap joint A butt joint between two pieces that
are secured by a riveted strap between them.

strapped elbow Same as drop elbow.

strapped wall See battened wall.

strapping 1. Battens which support a lath-and-
plaster construction. 2. Same as banding, 4.

strapwork 1. Any type of ornament consisting
of narrow fillets or bands that are folded, crossed,
or interlaced. 2. Interlacing decorative bands
found within gables; especially found in Tudor
architecture and Tudor Revival, as well as in
northern Europe.

strapwork on a Tudor style house

stratification l.The separation of overwet or
overvibrated concrete into horizontal layers
with increasingly lighter material toward the
top; water, laitance, mortar, and coarse aggregate
tend to occupy successively lower positions in
that order. 2. A layered structure in concrete
resulting from the placement of successive
batches that differ in appearance.

stratified rock Layered earth materials,
deposited as successive beds of sediment and
solidified by compaction, cementation, or crys-
tallization; same as sedimentary rock, although
not all the latter shows visible stratification.

stratum A bed of sedimentary rock or earth.

straw bale house A dwelling whose walls are
constructed of bales of straw, compressed and
wire-tied or string-tied into large units and built
up on a concrete slab as if they were oversized
bricks; they are reinforced with vertical poles
that pierce the bales. When thoroughly dry, the
walls are usually finished with a coat of stucco or
adobe plaster to promote sanitation, fire safety,
and protection against the weather; the bales
provide excellent thermal insulation. Especially
found in the farm regions of midwestern United
States.

951

strawboard

strawboard, compressed straw slab Straw
mixed with a bonding ingredient and com-
pressed into a board-type material.

straw-hat theater A theater used only in the
summertime.

straw shed An extension at the rear of a barn,
usually on one side, used primarily for the stor-
age of straw; it may also be a two-story structure
in which the upper story is used to store hay and
the lower story is used to store farm machinery.

stray light Incidental light reaching an area
from sources used to light other areas.

streamlined specification A specification
containing adequate technical information for
the construction of the work, 1 but written in an
abbreviated manner.

streamline flow The flow of a liquid or gas
past a solid body in a manner so that the veloc-
ity of the fluid, at every point, does not change
with time.

Streamline Moderne, Streamline Modern
A phase of Art Deco that emphasizes the con-
tours that offer minimum resistance to fluid flow,
resulting in emphasis on the horizontal aspects
of design. Usually characterized by curved end
walls, rounded corners; glass block; flush win-
dows; white or light-colored stucco walls; hori-
zontal stainless-steel railings.

stream shingle Flat pieces of thin-bedded or
foliated rock taken from the channel of a small,
high-gradient stream; has a sloped overlapping
pattern resembling shingling.

street A public thoroughfare, usually paved,
including all area within the right-of-way, such
as sidewalks; a public way.

street elbow Same as service ell.

street elbow

street ell See service ell.

street floor 1. In a building, that floor which is
nearest to street level; usually not more than a
half story above or below street level; often the
main floor of the building. 2. To qualify as a

street floor under certain codes in the US, the
floor level may not be more than 2 1 in. above or
more than 12 in. below grade level at the main
entrance.

street furniture The benches, signs, lights,
fixtures, and receptacles provided as part of the
design of a street right-of-way.

street lighting luminaire A complete light-
ing device consisting of a light source together
with its appurtenances such as a globe, reflector,
refractor, housing, and such support as is integral
with the housing; the pole, post, and bracket are
not included.

street lighting unit The assembly of a pole or
lamppost with a bracket and a street lighting
luminaire.

street line 1 . A lot line dividing a lot or other
area from a street. 2. A side boundary of a street,
defined by the instrument creating that street as
having a stated width.

street main See gas main and water main.

street pavement The exposed or wearing sur-
face of a roadway.

street projection Any part of a structure that
extends beyond the street building line, including
but not limited to architectural features, mar-
quees, fire escapes, flagpoles, marquees, and signs.

street 'wall The wall of the building nearest a
street line abutting the property.

strength Of a material, the capability of the
material to resist physical forces imposed on it.

strength design A fundamental design tech-
nique for providing a margin of safety in a
structure.

stress The internal forces set up at a point in an
elastic material by the action of external forces;
expressed in units of force per unit area, e.g.,
pounds per square inch or kilograms per square
millimeter.

stress analysis See structural analysis.

stress concentration Localized stress (usually
as a result of localized loading or changes in
geometry) which is significantly higher than the
average stress.

stress corrosion Corrosion of a metal which is
accelerated by stress.

stress corrosion cracking Failure in a metal
as a result of cracks caused by the simultaneous

952

stretcher bond

interaction of sustained tensile stress at an
exposed surface with the chemical or electro-
chemical effects of the environment to which it
is exposed.

stress-corrosion cracking A failure of met-
als by cracking as a result of corrosion and stress.

stress crack An external or internal crack in a
plastic caused by internal or external tensile
stresses; environmental conditions frequently
accelerate the development of such cracks. Also
see crazing.

stress cracking The cracking of a weld or a
base metal which contains residual stresses.

stress diagram See stress-strain diagram.

stressed sandwich panel Same as stressed-

skin panel,
stressed-skin construction Construction in

which a thin material, on the exterior surface of
a building, is utilized to carry loads.

stressed-skin panel A panel composed of a
core which is faced on both sides with plywood
or another suitable sheet material, providing
strength for the complete assembly.

stress factor of safety The ratio between the

stress at failure to the maximum permissible

stress.
stress-graded lumber Lumber graded for

strength according to growth rate, grain slope,

and defects.

stressing end In prestressed concrete, the end

of the tendon from which the load is applied,
when tendons are stressed from one end only.
stress-number curve In fatigue testing, a
curve showing the relation between the value of
stress and the number of cycles at that value of
stress required to produce failure in the test
specimen.

stress range The difference between the maxi-
mum and minimum values of stress in a member
which result from different loading conditions.

stress relaxation The time-dependent decrease
in stress in a constrained material under a con-
stant load, 1 .

stress-relief heat treatment, stress reliev-
ing The uniform heating of a material or
structure to a temperature high enough to
relieve the major portion of the residual stresses,
followed by uniform cooling.

stress relieving See stress-relief heat treatment.

stress-strain diagram A diagram in which
corresponding values of stress are plotted against
strain; values of stress usually are plotted as ordi-
nates (vertically) and values of strain as abscissas
(horizontally).

stretch An area of patent glazing.

stretcher A masonry unit laid horizontally
with its length in the direction of the face of
the wall.

STRETCHER

stretcher laid in a wall

STRETCHER STRETCHER STRETCHER
(3 CORE) (2C0RE)

hollow-masonry-unit stretchers

stretcher block A concrete masonry unit
which is laid as a stretcher.

stretcher bond, running bond, stretching
bond In masonry, a bond in which bricks or
stones are laid lengthwise; all courses are laid as

stretcher bond

953

stretcher course

stretchers with the vertical joints of one course
falling midway between those of adjacent
courses.

stretcher course, stretching course A
course consisting only of stretchers.

stretcher face The long face of an exposed
brick which is laid as a stretcher.

stretcher leveling The flattening of metal
sheets by stretching them mechanically.

stretch-in carpet installation The installa-
tion of carpet by stretching it over carpet under-
layment and attaching it to a tackless strip
around the perimeter of the carpet.

stretching bond Same as stretcher bond.

stretching course A stretcher course.

stretching piece A tie, strut, or brace.

stria l.A fillet. 2. A rib, esp. one repeated to
give texture.

striated Fluted, as a column.

stria tura The fluting on columns.

striga A fluting of a column.

strigil ornament In Roman architecture, a
decoration of a flat member, as a fascia, with a
repetition of slightly curved vertical flutings or
reedings.

strike l.In stone setting or bricklaying, to
finish a mortar joint with a stroke of the
trowel, simultaneously removing extruding
mortar and smoothing the surface of the mor-
tar remaining in the joint; strike off. 2. A
strike plate.

strike backset On a doorframe, the distance
from the stop to the edge of the strike plate
cutout.

strike block A plane, shorter than a jointer
plane, used for fitting a short joint.

strike edge See leading edge.

strike jamb, lock jamb The vertical member

of a doorframe on which the strike plate is

installed.

strike off 1. To use a straight wood or metal bar
for removing material (from a newly plastered or
mortared work or from a freshly laid concrete
surface) which is in excess of that required to fill
a form evenly or to level the surface. 2. The
wood or metal bar used for this purpose. 3. See
strike, 1 .

strike plate, strike, striking plate A metal
plate or box which is set in a doorjamb and is
either pierced or recessed to receive the bolt or
latch of a lock, fixed on a door. Also see box
strike plate.

striker A slightly beveled metal plate, set in the
jamb of a door to receive and guide a door latch
to its socket in closing.

strike reinforcement A metal tab in a hol-
low-metal doorframe, to which the strike plate is
attached; strengthens the frame.

strike stile Same as lock stile.
strike-through See bleed-through.

striking 1. Cutting a molding with a plane.
2. Removing temporary supports from a structure.

striking-off lines In plastering, markings for
cornice work, on ceilings or walls.

striking plate See strike plate.

striking point The center of curvature of a cir-
cular arc; the point from which such an arc is
drawn.

striking stile See lock stile.

string 1 . In a stair, an inclined board which sup-
ports the end of the steps; also called a stringer.
2. In a lattice roof truss, a horizontal tie. 3. A
stringcourse. Also called stringer, stringboard, or
face string. For specific types, see closed string,
face string, finish string, open string, outer
string, rough string, stair string.

string, 1

954

strip heater

stringboard Same as face string.

stringcourse, belt course A horizontal band
of masonry, generally narrower than other
courses, extending across the facade of a struc-
ture and in some instances encircling such deco-
rative features as pillars or engaged columns;
may be flush or projecting, and flat-surfaced,
molded, or richly carved; a bond course.

stringcourse

string development Same as ribbon develop-
ment,
stringer l.A string, 1. 2. A stringpiece. 3. A

long, heavy horizontal timber which connects
the posts in a frame which supports a floor.

stringer bead In welding, a type of bead which
is made by moving the welding electrode in a
direction parallel to the axis of the bead, without
appreciable transverse oscillation.

stringiness The property of an adhesive
that results in the formation of filaments or
threads when the adhesive transfer surfaces are
separated.

stringing mortar The process of spreading
enough mortar on a bed to lay several masonry
units at one time.

stringpiece In construction or shoring, any
long, heavy horizontal timber.

string wall See string, 1.

strip 1 . Any material which is long and narrow,
usually of uniform width. 2. See board, 1. 3. To
damage the threads on a nut or bolt. 4. To
remove formwork.

strip board See strip core.

strip building Building dwellings, usually low-
cost, in long parallel rows, using a minimum of
land.

strip core, blockboard, loose core, strip
board A composite board; a coreboard
whose core is made up of strips of wood, either

laid separately or glued together; veneer is glued
to both faces of the core strips with its grain at
right angles to that in the strips.

strip diffuser See linear diffuser.

stripe See ribbon stripe.

stripe veneer Same as ribbon stripe.

strip flooring Hardwood finish flooring; nar-
row tongue-and-groove strips; commonly maple,
mahogany, oak, etc.

TONGUE

HOLLOW
BACK

THICKNESS -{

FACE WIDTH
B

strip flooring: A, side- and end-matched; B, matched; C,
square-edged

strip footing See strap footing.

strip foundation A continuous foundation in

which the length is considerably greater than
the breadth.
strip heater An electric heater, of the self-
regulating type, in the form of a strip containing
an electrical heating element that is wrapped
directly around a pipe; may be used to maintain
the desired delivery temperature at hot-water
outlets without the necessity of installing a cir-
culating hot-water system.

Copper conductor ^Sejmeonduelive
polymer

strip heater

955

strip lath

strip lath A narrow strip of diamond-mesh lath;
applied as a reinforcement over gypsum lath
joints or at a juncture of two different types of
plaster bases.

striplight l.See fluorescent strip. 2. A row of
lamps mounted in a trough with a reflecting
hood and color frames; used to flood an entire
theater stage or a selected area of the stage.

strip mall A shopping mall having a linear con-
figuration; often located along a highway.

strip mopping Mopping hot bitumen in strips,
usually about 8 in. (20 cm) wide with 4-in.
(10 cm) unmopped strips between.

stripped joint In brickwork, a type of raked
joint, used with bricks of rough texture.

stripped joint

stripper A liquid designed to remove coatings
by chemical and/or solvent action.

stripping 1. In grading an area in which a foun-
dation is to be built, the preliminary operation of
removing trees, shrubs, vegetation, and topsoil.
2. Removing old paint, wallpaper, distemper,
etc., by the use of a blowtorch, paint remover,
steam stripping appliance, stripping knife, or
other scraping tools. 3. Sealing the joint bet-
ween a metal sheet and a built-up roofing mem-
brane. 4. Taping the joints between insulation
boards.

stripping agent Same as release agent.

stripping felt A narrow strip of roofing used to
cover a metal flange of flashing.

stripping knife See broad knife.

stripping piece In formwork, a splayed narrow
member which is used to facilitate removal in a
confined space.

stripping shovel A power shovel which has

an especially long boom, permitting it to reach

farther and pile higher.
strip slates See asphalt shingles.
strip soaker In roofing, a strip of waterproof

material installed under each course of shingles,

slates, or tiles at a swept valley,
strip taping Same as stripping, 4; also see taping

strip.
strip welting See welting strip.
strip 'window A series of windows that forms a

horizontal band across the face of a building.
strix A flute, or concave canal; a fluting of a

column.
stroked 'work Stone which has been tooled so

as to produce a finely fluted surface.
stroll garden A garden designed to be viewed

from a footpath, which usually proceeds from

one of a series of vantage points to another.
strong axis The major principle axis of a cross

section.
strongback A frame attached to the back of a

concrete form to stiffen or reinforce it.
strong clay Pure clay that is essentially free of

any other substance.
stronghold See fortress, 1.
strong mortar A mortar made only with port-
land cement, without lime; has high shrinkage.
strong tower Same as keep.
Struc Abbr. for "structural."
struck joint l.A masonry joint from which

excess mortar has been removed by a stroke of

the trowel, leaving an approximately flush joint.

2. A horizontal masonry joint in which the

struck joint, 2

956

Structuralism

mortar is sloped inward and downward from the
lower edge of the upper brick, leaving a recess at
the bottom of the joint. 3. A weather-struck
joint.

struck molding, solid molding, stuck
molding A molding cut into rather than
added to or planted on a member.

structura A general term for masonry of the
ancient Greeks and Romans.

structura antiqua Same as opus incertum.

structural Said of a load-bearing member, ele-
ment, etc., of a building.

structural adhesive A bonding agent used to
prepare bonded joints which are able to sustain
very high loads.

structural analysis, stress analysis In
structural engineering, the analytical determina-
tion of the stresses in the elements of a structure
resulting from an applied load.

structural bond The union of two or more

masonry units so that the combination acts as a
single unit and provides the same structural
strength as a single unit of the same material.

structural clay facing tile Ceramic tile
designed for use in interior and exterior unplas-
tered walls, partitions, or columns.

structural clay tile A hollow masonry build-
ing unit composed of burnt clay, shale, fireclay,
or mixtures thereof, having parallel cells or cores
(or both) within a single tile.

structural clay tile units

structural concrete 1. Concrete, of a speci-
fied quality, which is used to carry a structural
load or to form an integral part of a structure.

structural connection A device for uniting
individual members of a structural assembly.

structural damage The loosening, twisting,
warping, cracking, distortion, or breaking of any
piece, or of any fastening or joint, in a structural
assembly, with a resulting loss of sustaining
capacity of the assembly.

structural design documents The plans,
design details, and job specifications prepared by
the structural designer.

structural drawings Drawings, usually pre-
pared by a structural engineers, of the design and
working drawings of a building's structure.

structural element One of the supporting
components of which a building is composed; for
example, a beam, column, floor, or wall.

structural engineering That branch of engi-
neering concerned with the design and
construction of structures to withstand physical
forces or displacements without danger of
collapse or without loss of serviceability or
function.

structural facing unit A building unit
having one or more faces designed to be
exposed in a finish wall; the specifications may
include color, finish, and any factor affecting
its appearance.

structural failure l.The loss of sustaining
capacity or stability. 2. Rupture of an essential
component of the structure. 3. A marked
increase in strain without an increase in load.
4. A deformation which increases much more
rapidly than the increase in imposed load.

structural frame All the members of a build-
ing or structure required to transmit loads to the
ground.

structural gasket See lock-strip gasket.

structural glass Glass, sometimes colored,
which is cast in the form of cubes, rectangular
(solid or hollow) blocks, tile, or large rectangular
plates; used widely for wall surfacing.

structural glazing Glass panels which are
held in place by highly adhesive silicone cement
at the joints between panels; eliminates the
need for metal mullions at these sites.

structural glued-laminated timber A
stress-rated assembly of especially selected and
prepared wood laminations which are securely
bonded together with adhesives.

Structuralism Based on the findings in anthro-
pology, ethnology, and psychology by Claude

957

structural lighting element

Levi-Strauss in his search for primordial societal
constructs or patterns which serve as the basis for
all later cultural developments, Structuralism in
architecture connotes the referral to basic struc-
tural forms, archeforms, from which architectural
design and construction can derive. The Dutch
architect, Aldo van Eyck, is often cited as a main
representative, although structural ideas have
also been expressed by early Le Corbusier, by
Louis Kahn, and by others.

structural lighting element A lighting ele-
ment that is built into a structure or that uses the
structure as a part of the luminaire.

structural lightweight concrete Structural
concrete made with lightweight aggregate; usually
weighs 90 to 115 lb per cu ft (1,440 to 1,840 kg
per cu m).

structural lumber Lumber consisting of the
following classifications: 1. Beams and stringers:
Lumber of rectangular cross section, 5 in. or
more thick and 8 in. or more wide; graded with
respect to its strength in bending when loaded
on the narrow face. 2. Joists and planks: Lumber
of rectangular cross section, 2 in. to (but not
including) 5 in. thick, and 4 in. or more wide;
graded with respect to its strength in bending
when loaded either on the narrow face as a joist
or on the wide face as a plank. 3. Posts and tim-
bers: Lumber of square or approximately square
cross section 5 in. by 5 in. and larger; graded pri-
marily for use as posts or columns carrying longi-
tudinal load but adapted for miscellaneous uses
in which strength in bending is not especially
important.

structural sealant A sealant capable of trans-
ferring either dynamic or static loads (or both)
across joint members exposed to the service
environments which are typical for the structure
involved.

structural shape A hot-rolled steel beam of
standardized cross section, temper, size, and
alloy; includes angle irons, channels, tees, I-
beams, and H-sections; commonly used for
structural purposes.

structural steel Steel, rolled in a variety of
shapes (such as beams, angles, bars, plates,
sheets, strips, etc.) and fabricated for use as load-
bearing structural members or elements.

structural steel fastener A fastener for con-
necting or attaching structural steel members to

other structural steel members, to supporting
elements, or to a concrete member forming a
composite section.

structural stonework Heavy load-bearing
masonry that supports weight in addition to
its own weight; contrasts with a masonry cur-
tain wall, 1 which does not support additional
weight.

structural tee A standard structural hot-rolled
steel member shaped like the letter T and
formed from cutting an I-beam in half.

structural terra cotta See structural clay tile.
structural timber connector See timber
connector.

structural timbers Structural lumber of

approximately square cross section that is 5 in.

(12.7 cm) on a side or larger; used primarily for

posts and columns.
structural wall A wall capable of supporting

an imposed load.

structura reticulata Same as opus reticulatum.

structure l.A combination of units con-
structed and so interconnected, in an organized
way, as to provide rigidity between its elements.
2. Any edifice.

structure-borne sound Sound that reaches a
point in a building, over at least part of its path,
by solid-borne transmission through the build-
ing structure.

structure height l.The vertical distance from
grade to the highest point of a structure; the over-
all height. 2. For a roof structure, the mean level
of the roof to the highest point of such a structure.

strut A brace or any piece of a frame which
resists thrusts in the direction of its own length;
may be upright, diagonal, or horizontal.

strutbeam Same as collar beam.

strut guide In a doorframe, a metal piece
within the throat opening of the frame; serves as
a guide for the ceiling strut.

strutting 1. Diagonal braces between joists to
prevent side deflection. 2. See cross bridging.

strutting beam Same as collar beam.

strutting piece Same as straining beam.

Stuart architecture English architecture of the
late Reniassance from about 1603 to 1688, espe-
cially during the period of the Stuart dynasty.

958

stud opening

stub A piece or part of something sticking out,

as the nib on a tile.
stub mortise A mortise which does not pass

through the entire thickness of the timber in

which it is made; a blind mortise.

M T

stub mortise (M); stub tenon (T)

stub mortise and tenon Same as blind mor-
tise and tenon joint.

stub pile A short, thick pile, 1.

stub tenon A short tenon which does not pass
completely through the material in which the
mortise is cut; fits into a stub mortise.

stub wall A low wall, monolithically placed
with a concrete floor (or other members) so as to
provide for the control and attachment of wall
forms.

stuc Plaster applied to form an imitation stone.

stucco 1 . An exterior finish, composed of some
combination of portland cement, lime, and
sand, which are mixed with water, which dries to
a very hard textured surface. 2. A synthetic exte-
rior finish such as an exterior insulation and fin-
ishing system, containing materials other than
stucco, 1, for example, containing an epoxy as a
binder. 3. A fine plaster used for decorative
work, moldings, or cornices. 4. A partially or
fully calcined gypsum that has not yet been
processed into a finished product.

stucco marble An imitation marble (faux
marbre) made of stucco; occasionally used in
European church architecture of the Baroque
period (17th and 18th centuries). Various colors
of stucco were allowed to run together when wet
so as to achieve a desired visual effect.

stucco mesh A lightweight galvanized wire
netting usually having a hexagonal mesh; some-
times used in stucco work.

stuck molding See struck molding.

stud 1. An upright post or support, esp. one of a
series of vertical structural members which act as
the supporting elements in a wall or partition. 2.
A cylindrical rod of moderate length, threaded
on one or both ends or throughout its entire
length.

stud, 1

flHDWH)

i£ innn

stud, 2

stud anchor An anchor used in a wall built

with steel or wood studs.
stud and mud Same as wattle and daub.
stud bolt A stud, 2.

studding 1. Same as stud. 2. The material from
which wood studs are cut.

stud driver A device for driving a hardened
steel nail (a stud) into concrete or other hard
material; the driver, containing a stud, is held
against the concrete; then a blow on the head of
the driver forces the stud into the concrete.

stud fixing Same as stud anchor.

stud gun A stud driver in which the impact is
provided by the firing of a blank cartridge.

studio 1 . The working room of an artist or a
place where an art form is pursued. 2. A room
equipped for the recording of music or the trans-
mission of radio or television broadcasts.

studio apartment 1 . An apartment consist-
ing of a single, multifunctional room which
serves as a living room, dining room, and bed-
room and which contains kitchen facilities;
has a separate bathroom. 2. An apartment,
with large windows and high ceilings, used as
an artist's studio.

stud opening A rough opening in a wood
framework.

959

stud partition

stud partition A partition using studs, 1 as the

vertical structural members; usually faced with
wallboard.

stud partition

stud shooting 1 . Inserting studs by means of a
stud gun. 2. Driving a hardened steel nail or bolt
into concrete by means of a stud gun.

Stud wall See stud partition.

stud welding An arc-welding process in which
coalescence is produced by heating with an arc
between a metal stud and the other work part
until the surfaces to be joined are properly heated;
then they are brought together under pressure.

studwork 1. Brickwork interspaced with studs.
2. A construction with alternating bricks and
studs.

study 1. A room or alcove of a house or apart-
ment used primarily as a place for reading, writ-
ing, and study. It often embodies the features of
a private office and private library. 2. A prelimi-
nary sketch or drawing to facilitate the develop-
ment of a design.

stuff l.Sawn timber; stock lumber. 2. See fine
stuff.

stuffers See carpet staffers.

stuffing box A packing gland surrounding a
shaft to prevent leakage; commonly used on
water pumps.

stugging Same as dabbing.

stumper An attachment on a bulldozer, used in
the removal of tree stumps.

stump tenon A stub tenon which is nonuni-
form in thickness, being wider at the root for
additional strength.

stump tracery Tracery, late German Gothic,
whose interpenetrating bars are cut off like
stumps.

stump tenon

stump veneer See butt veneer.
stumpwood See buttwood.

stunning The deep scoring or bruising of build-
ing stone, esp. by careless cutting.

stupa, tope A Buddhist memorial mound,
erected to enshrine a relic or to commemorate a
sacred site; consists of an artificial mound, raised
on a platform and surrounded by an outer ambu-
latory with a stone railing and four gateways,
crowned by a multiple sunshade.

stupa topped by a chattravali

ST W On drawings, abbr. for storm water.

style See architectural style.

Style Moderne See Art Moderne and Art

Deco.
Style Rayonnant See Rayonnant Style.
stylobate 1. Strictly, the single top course of

the three steps of the crepidoma upon which the

960

subfeeder

stylobate

columns rest directly. 2. Any continuous base,
plinth, or pedestal, upon which a row of columns
is set. Also see stereobate.

stylolite A jointed or irregular columnar struc-
ture occasionally found in beds of limestone,
uniting the adjoining surfaces of two layers of
rock.

styrene-butadiene rubber A widely used
synthetic rubber made by copolymerizing
styrene and butadiene monomers.

SUB On drawings, abbr. for "substitute."

subarch One of two or more minor arches
beneath and enclosed by an outer arch.

subarcuation Window tracery having subordi-
nate arches.

subbase The lowest projection of a base mold-
ing or baseboard with more than one horizontal
subdivision.

subbase course For the support of paving
materials, a layer of granular material applied to
the subgrade in a predetermined depth; pro-
vides underpavement drainage and reduces frost
damage.

subbasement The level, or levels, of a building
below the basement.

subbidder One who tenders to a bidder on a
prime contract a proposal to provide materials
and/or labor.

sub-buck Asubframe, 1.

subbuilding drainage system A building-
drainage system which cannot drain by gravity
into the sewer.

subcasing, blind casing 1. A rough buck. 2.
A subframe.

subcellar The level, or levels, of a building
below the cellar.

subcompartment One of the areas into
which a building can be divided to provide
protection against fire and smoke; the avail-
ability of such areas reduces the distance that
must be travelled to a place of safety in the
event of fire.

subcontract An agreement between a prime or
general contractor and a subcontractor for the
execution of a portion of the contractual obliga-
tion of the prime contractor to the owner.

subcontractor A person or organization who
has a direct contract with a prime contractor to
perform a portion of the work at the site.

subcontractor bond A performance bond
given by a subcontractor to the general contrac-
tor which guarantees performance of a contract
and the payment of bills for labor and material.

subcrust See cushion course.

subdiagonal In a truss, an intermediate diago-
nal of a web, 1 joining a chord with a main
diagonal.

subdivided truss Any truss having a sec-
ondary framework placed in one or more panels,
7 to shorten the effective length of the panels.

subdivision A tract of land divided into resi-
dential lots.

subdivision regulations Local ordinances
which specify the standards and conditions under
which a tract of land can be subdivided. Origi-
nally directed at street layout and construction
specifications, many regulations now stipulate the
general design of street lighting and signs, side-
walks, sewage disposal, and water-supply systems;
others require the dedication of land for schools,
parks, and other community facilities within the
subdivision.

subdrain See building subdrain.

subfeeder In electric wiring, a feeder which
originates at a distribution center other than the
main distribution center and supplies one or
more branch-circuit distribution centers.

961

subfloor

subfloor, blind floor, counterfloor A

rough floor, laid on joists, which serves as a base
for the finished floor; is used as a working plat-
form during construction, may act as a structural
diaphragm to resist lateral stresses.
subflooring The material used in constructing
the subfloor; usually plywood sheets or an infe-
rior grade of soft lumber.

subflooring

subframe, rough buck, sub-buck l.A

secondary frame, usually formed of wood mem-
bers or channel-shaped metal members, which
supports the finish frame of a door or window;
attached to the wall in which the finished frame,
knocked-down frame, door casing, or door lin-
ing is set; a buck frame. 2. A frame which sup-
ports a panel used as a wall finish.

subgrade l.The soil prepared and compacted
to support a structure or a pavement system; the
base portion of any surfaced area, the elevation
of which is lower than that of the finished grade.
2. The elevation of the bottom of a trench in
which a sewer or pipeline is laid.

subgrade modulus Same as coefficient of
subgrade reaction.

subgrade reaction Same as contact pressure.

subheading A subdivision of a heading used
in the filing system (Part Two of the uniform
system).

subhouse drainage system Same as sub-
building drainage system.

subjective brightness See brightness.

subject to mortgage A conveyance of prop-
erty will be subject to an existing mortgage if the

purchaser has actual or constructive notice of it,
e.g., if a mortgage of real property has been
recorded in the land records. If there is a default
in mortgage payments, the mortgagee may fore-
close. The new owner usually keeps up the mort-
gage payments in order to preserve his interest in
the property. But if he decides not to do so (if, for
example, the property's value drops below that
of the amount still unpaid on the mortgage), he
is not personally liable to make the mortgage
payments unless he has agreed to do so. See
assumption of mortgage.

sublease A lease by a tenant to a subtenant of

part or all of the premises leased by him, for part

or all of the term of his lease.
sublica In ancient construction, a pile driven

into the earth, or into ground covered by water,

to support a structure.

sublight A small sash or light (usually fixed) at
the bottom of a window.

submerged arc welding An arc-welding
process resulting from heat from an arc drawn
between a bare metal electrode and the work;
the arc is shielded by a blanket of granular,
fusible metal on the work; pressure is not used.

submersible pump A type of pump designed
with an integral motor and liquid-handling sec-
tion in a watertight casing that can be lowered
directly into the liquid to be pumped.

submittals Materials such as samples or manu-
facturers' data that are submitted to the archi-
tect for approval; usually a requirement of the
contract documents.

suborder A secondary architectural order,
introduced chiefly for decoration, as distin-
guished from a main order of a structure.

subordinate lien Any subsequent (second,
third, fourth, etc.) mortgage lien. In the event of
foreclosure, holders of such liens may resort to
the property for payment only to the extent of
any surplus after prior liens have been paid off.
Priority is usually determined by the chronolog-
ical sequence in which the mortgages were cre-
ated, but may be varied by agreement among the
parties.

subparagraph In the AIA documents, the first
subdivision of a paragraph, identified by three
numerals, e.g., 3.3.3; may be subdivided into
clauses.

962

subsystem

subplatform In metal stair construction, the
metal subfloor over which a fill is placed to pro-
vide a platform.

subplinth A secondary plinth sometimes
placed under the usual one in column and
pedestal bases.

subpost, car frame An elevator car frame all
of whose members are located below the car
platform.

subpurlin A light member of an intermediate
system of beams which rests on and usually runs
at right angles to purlins in a roof structure.

subrail, shoe On a staircase, a member which
is fixed to the upper edge of a close string to
receive the balusters.

subrogation The substitution of one person for
another with respect to legal rights such as a
right of recovery; occurs when a third person,
such as an insurance company, has paid a debt of
another or claim against another and succeeds to
all legal rights which the debtor or person
against whom the claim was asserted may have
against other persons.

subsealing The placing of a waterproof mate-
rial under an existing pavement, or the like, to
prevent the flow of water through the pavement
and to fill the voids under the pavement.

subsellium Same as miserere.

subsidence A sinking of an entire area, in con-
trast to the settlement of an individual structure.

subsill 1 . A subsidiary sill member fitted to a
window frame; serves as a stop for screens;
causes water to drip farther away from the wall
surface; also called a sill drip molding. 2. A sub-
sidiary doorsill which is fixed to the groundsill.

subsoil The bed or stratum of earth which lies
immediately below the surface soil.

subsoil drain A drain installed for collecting

subsurface or seepage water and conveying it to a

place of disposal.
subsoil water Water which has accumulated

in the stratum of earth immediately below the

surface soil.
substantial completion See certificate of

substantial completion.
substantial improvement Any alteration,

improvement, reconstruction, or repair of a

building, the cost of which equals or exceeds a

code-specified percentage of its market value:
(a) either before the work is started, or (b) if the
building has been damaged and is being restored,
before such damage occurred.

substation The electrical equipment (e.g., cir-
cuit breakers, switches, transformers, and busses)
associated with the service entrance or other
major transformation and distribution equip-
ment concentrated in one location in areas of
building complexes or on floors of high-rise
buildings.

substitution A material or process offered in
lieu of, and as being equivalent to, a specified
material or process.

substrate 1 . The underlying material to which
a finish is applied, or by which it is supported.
2. A material upon which an adhesive, film,
coating, etc., is applied.

substrate failure At a joint in a concrete wall,
a failure that occurs where the concrete surface
is weak; caused by a sealant of high tensile
strength which tears off concrete or mortar from
the face of the joint.

substructure The foundation or understruc-
ture of a building; supports the superstructure.

sub- subcontractor A person or organization
who has a direct or indirect contract with a sub-
contractor to perform a portion of the work at
the site.

subsurface course The top course of pave-
ment providing a surface which is resistant to
traffic abrasion.

subsurface investigation Same as geotech-
nical investigation.

subsurface sand filter A wide bed, consist-
ing of a number of lines of perforated pipe or
drain tile surrounded by clean coarse aggre-
gate, containing an intermediate layer of sand
as filtering material, and provided with a sys-
tem of underdrains for carrying off the filtered
sewage.

subsurface sewage disposal system A sys-
tem for the treatment and disposal of domestic
sewage by means of a septic tank and a soil
absorption system.

subsurface utility Any public utility which is

underground.

subsystem See building subsystem.

963

suburb

suburb An outlying area, in or near a city, of
predominantly residential land use.

subvertical The upright member in a subdi-
vided panel of a truss running from midpanel
point to the chord.

subway l.(US) An underground, intraurban
passenger railway. 2. (Brit.) An underground
pedestrian passageway sometimes containing
building maintenance and service elements.

successful bidder Same as selected bidder.

sucker A shoot rising from a subterranean root
or stem of a plant.

suction l.In plastering, the absorption of
water from a plaster finish coat by the base coat
(or the base, such as block or gypsum lath), thus
providing a better bond and causing it to adhere
to the base coat. 2. The adhesion of mortar to
bricks.

suction head The energy per unit weight of
fluid on the suction side of a pump.

suction lift Same as suction head.

suction pump A pump which raises water, or
draws water in plumbing, by producing a partial
vacuum within a pipe.

suction rate For bricks, same as absorption rate.

sudatorium In an ancient Roman bath, a hot
room for inducing sweat, used by athletes.

Suffolk latch A type of thumb latch for doors;
originally fabricated of iron wrought by hand in
England. Attractive in appearance and available
in many different designs; unlike the Norfolk
latch, it has no plate behind the thumb latch to
protect the door finish.

sugarhouse A building or shed, usually located
in a grove of sugar maple trees, in which maple
sugar is made by boiling the sap of the trees to
evaporate its water content.

sugar pine A durable, moderately even-
grained wood, widely used as factory lumber, esp.
for doors and frames.

suite A connected group of rooms arranged or
designed to be used as a unit.

sulfate attack A chemical or physical reac-
tion, or both, between sulfates (in ground
water or in the soil) and concrete or mortar;
primarily damaging to the cement paste
matrix; reduced in concrete made with sulfate-
resistant cement.

sulfate plaster Same as gypsum plaster.

sulfate resistance The ability of concrete or
mortar to withstand sulfate attack.

sulfate-resistant cement A portland cement
which is low in tricalcium aluminate; has a
reduced susceptibility to attack by dissolved sul-
fates in water or soils; type V portland cement.

sulfide staining The formation of dark stains in
a paint film, as a result of the reaction of atmos-
pheric hydrogen sulfide with metallic compounds
such as lead, mercury, or copper in the paint.

sulfoaluminate cement See expansive ce-
ment.

sulfur cement A cement of clay or other tena-
cious infusible substance, usually with additives
such as sulfur, metallic oxides, silica, or carbon;
used for sealing joints and seams and high-tem-
perature coatings or coverings; also called lute.

sullage 1. Drainage, sewage, or waste. 2. Sedi-
ment or silt which is carried and deposited by
flowing water.

Sullivanesque A term descriptive of the archi-
tectural style and decorative designs of Louis H.
Sullivan (1856-1924), an important figure in
the development of modern functional architec-
ture. He is known for his famous statement that
"Form ever follows function," and is especially
noted for his tripartite scheme for the design of
tall buildings. This term is also applied to his
continuous foliated motifs, which are somewhat
Art Nouveau in character.

Sumerian architecture A monumental
architecture developed by the Sumerians, who
dominated southern Mesopotamia from the end
of the 4th to the end of the 3rd millennium B.C.
This architecture made use of locally available
building materials: tall rushes and clay, tied bun-
dles of reeds, and wattle and daub. To give char-
acter and structural strength to the mud-brick
walls, the walls were articulated by buttresses or
built with alternating pilasters and recesses.

summer 1 . A horizontal beam supporting the
ends of floor joists or resting on posts and sup-
porting the wall above; also called a sum-
mertree. 2. Any large timber or beam which
serves as a bearing surface. 3. The lintel of a door
or window; a breastsummer. 4. A stone laid on a
column and serving as a support for construction
above, as in the construction of an arch.

964

sunken pit

the normal grade of the building gravity
drainage system so the discharge in the pit space
must be emptied by means of a sump pump,
sump pump, ejector A pump used to remove
the accumulated waste in a sump.

summer, 4: S

summerbeam l.A massive horizontal beam
in the ceiling of an early timber-framed house;
usually joined at their ends to girts and support-
ing the floor above, or acting as a binding beam
running in a transverse direction, connecting
one post to another. After about 1750, they were
replaced by a number of heavier floor joists, thus
making it possible to plaster the entire ceiling as
a single horizontal surface. Also called a summer
or summertree. See illustration under timber-
framed house. 2. Same as breastsummer. 3.
Same as fireplace lintel or manteltree.

summer house 1 . A home in the country used
as a summer residence. 2. A garden house of
light airy design used in the summer for protec-
tion from the sun.

summer kitchen A supplementary kitchen
located near, but detached from, a large home;
especially used during hot weather to avoid
overheating the house.

summer piece A fireboard.

summer stone Same as summer, 4.

summertree See summer, 1.

summerwood Wood which is formed during
the later part of the growing season; character-
ized by compact, thick-walled cells; denser than
spring wood.

sump l.A pit, tank, basin, or receptacle which
receives sewage or liquid waste, located below
the normal grade of the gravity system, and
which must be emptied by mechanical means. 2.
A reservoir sometimes forming part of a roof
drain. 3. A depression in a roof deck where the
roof drain is located.

sump pit A pit or tank that receives clear liquid
wastes not containing organic material or com-
pounds subject to decomposition; located below

sump pump

sump vent A vent from a pneumatic sewage

ejector which terminates in the open air.
sunblind Same as shade screen.
sunburst light A fanlight.

Sunday house A small house, usually consist-
ing of a single room with a fireplace, commonly
built near a house of religious worship for use
one night a week. A farmer or rancher who lived
some distance away would trade or sell produce
on Saturday, stay overnight in the house, attend
church services on Sunday, and then return
home; also see Sabbath house.

sun deck A roof area, balcony, open porch,
etc., which is exposed to the sun.

sun disk A disk with wings, emblematic of the
sun, used in Egyptian Revival architecture.

sunk chamfer Same as hollow chamfer.

sunk draft A margin around a building stone
which is sunk below the face of the stone to give
it a raised appearance.

sunken garden A garden, sometimes geomet-
rically planned, at a level below prevailing
grade, or surrounded by raised terraces.

sunken joint A type of defect in a veneer
panel; a surface depression which develops
above a joint in the core construction below.

sunken pit A pit which is lower (on all sides)
than the surrounding area.

965

sunk face

sunk face A building stone having a face from
which material has been removed to give the
stone the appearance of a sunken panel.

sunk fence A ha-ha.

sunk fillet A fillet formed by a groove in a
plane surface.

sunk fillet

sunk gutter A concealed gutter.

sunk molding A molding slightly recessed

behind the surface on which it is located.
sunk panel A panel recessed below the surface

of its surrounding framing or carved into solid

masonry or timber.
sunk relief A carving or other type of relief

that does not project beyond the flat surface on

which it is cut; also called cavo-relievo.

sunk shelf A narrow shelf serving as a plate rail.

sunk weathered Descriptive of a weathered, 2
surface which is sunk below the original surface
of the member.

sun-porch See solarium.

sun room Same as solarium.

sun screen See shade screen.

SUP On drawings, abbr. for "supply."

superabacus An impost block.

superblock A larger than usual residential
block, having no through traffic.

supercapital An impost block.

supercilium l.The fillet above the upper-
most molding or cyma of a cornice. 2. The
small fillet on either side of the scotia of an
Ionic base.

supercolumniation The placing of one order
above another.

sunk relief

supercolumniation: Ionic pillars on Doric

superficial measure See face measure, 1.

super foot A square foot (0.0929 sq m).

superheated steam Steam at a temperature
higher than the saturation temperature corre-
sponding to the pressure.

superheater A heat exchanger for heating
steam above 212°F (100°C) at atmospheric
pressure.

966

supply grille

superimposed drainage l.A naturally
evolved drainage system having little relation to
present geological structure because of erosion
occurring after the system's development. 2. A
drainage system purposely designed against
existing geological structure.

superimposed load The live load which is
imposed on a structure.

superintendence The work of the contrac-
tor's representative at a construction site.

superintendent At a construction site, the con-
tractor's representative who is responsible for con-
tinuous field supervision, coordination, and
completion of the work and, unless another per-
son is designated in writing by the contractor to
the owner and the architect, for the prevention of
accidents.

supermarket A large, self-service, retail mar-
ket which sells food, household goods, and
household merchandise.

supernatant liquid In a paint can, the liq-
uid layer which rests upon a layer of heavier
pigments and other matter in the bottom of
the can.

superplasticizer An additive that increases
the workability of a concrete mixture or a mortar
mixture.

superposition Same as supercolumniation.

superstructure l.That part of a building or
structure which is above the level of the adjoin-
ing ground or the level of the foundation. 2.
Any structure built on something else, as a
building on its foundation; that part of a struc-
ture which receives the live load directly.

supersulfated cement A hydraulic cement
made by intimately intergrinding a mixture of
granulated blast-furnace slag, calcium sulfate,
and a small amount of lime, cement, or cement
clinker; the content of sulfate exceeds that for
Portland blast-furnace slag cement.

supervision The observation and inspection of
construction work in order to ensure conformity
with the contract documents; direction of the
work, 1 by contractor's personnel. Supervision is
neither a duty nor a responsibility of the archi-
tect as part of his basic professional services.

supervisory device In a fire sprinkler sys-
tem, a device which supervises its condition of
operation.

supplemental conditions Same as supple-
mentary conditions.

supplemental general conditions Written
modifications to the general conditions of the
contract documents which become part of the
documents.

supplemental instruction A change in a
contract made for purposes of clarification;
does not alter the cost or schedule of the
contract.

supplemental instructions to bidders

Written modifications to the instructions to
bidders that become part of the bidding require-
ments.

supplemental vertical exit An enclosed
stair, ramp, or escalator providing means of
egress to an area of refuge at another area near
the street floor.

supplementary conditions A part of the
contract documents which supplements and may
also modify provisions of the general conditions.
Also see conditions of the contract.

supplementary lighting Lighting used to
provide an additional quantity and quality of
illumination, not obtained by the general light-
ing system; usually provides for specific work
requirements.

supplier Any commercial firm that supplies
components, fixtures, materials, or parts used on
a construction project.

supply air In an air-conditioning system, the
air which is delivered to the conditioned space
or spaces.

supply bond A bond which guarantees that
materials delivered comply with contract docu-
ments.

supply fan A fan that delivers supply air.

supply fixture unit A measure of the proba-
ble demand on the water supply by various
types of plumbing fixtures; for a particular
fixture the value of the supply fixture unit
depends on its volume rate of supply, on the
time duration of a single supply operation, and
on the average time between successive
operations.

supply grille A grille, 2 through which air is
supplied to an air-conditioned space. (See illus-
tration p. 968.)

967

supply mains

supply grille

supply mains The pipes through which the
heating or cooling medium of a system flows
from the source of heat or refrigeration to the
runouts and risers leading to the heating or cool-
ing units.

supply opening, supply outlet Same as air
outlet.

supply pipe See service pipe, 1.

supply system An assembly of connected
ducts, air passages or plenums, and fittings
through which air, heated in a heat exchanger, is
conducted from the heat exchanger to the space
or spaces to be heated.

supporting clamp A clamp used to support
vertical pipes, particularly where they penetrate
a building slab or are in a pipe chase.

Floor

stab

is)

SUPSD On drawings, abbr. for "supersede."
SUPT On drawings, abbr. for "superintendent."
SUPV On drawings, abbr. for "supervise."
SUR On drawings, abbr. for "surface."

surbase 1 . The crowning moldings or cornice of
a pedestal. 2. A border or molding above a base
or dado. 3. The molding at the top of a base-
board.

surbase, 1 a

surbased arch An arch whose rise is less than

half the span.
surcharge The vertical load applied at the

ground surface or above the level of the bottom

of a footing.
surcharged earth Earth which is above the

level of the top of a retaining wall.

Surcharged
earth

**• *•% .\.-\\

surcharged earth

surcharged wall A retaining wall carrying
surcharged earth.

sure post A vertical timber that provides
added support for a load imposed from above;
for example, a vertical timber placed below a
beam or sill.

968

surface-mounted luminaire

surety A person or organization who, for a con-
sideration, promises in writing to make good the
debt or default of another.

surety bond A legal instrument under which
one party agrees to answer to another party for
the debt, default, or failure to perform of a third
party.

surface-active agent l.In unhardened mix-
tures of concrete, an additive which has the
ability to modify the surface tension of the mix-
ing water, thereby facilitating the wetting and
penetrating action of the water, and/or assisting
the emulsifying, dispersing, solubilizing, foam-
ing, or frothing of other additives. 2. Same as
surfactant.

surface arcade Same as blind arcade.

surface astragal A surface-mounted astragal.

surface bolt A rod or bolt mounted on the face
of the inactive door of a pair, to lock it to the
frame and/or sill; operated manually by means of
a small knob.

surface bonding The bonding of dry-laid
masonry by a thin layer of fiber-reinforced
mortar.

surface burning characteristic See flame-
spread index.

surface check A check, 1 near the surface of a
piece of lumber.

surface condensation The formation of
water on the exterior surface of cold pipes (or
the like) when the temperature of the air falls
below its dew point (i.e., the temperature at
which the air is fully saturated).

surface course The exposed surface of paving
designed to withstand wear by traffic.

surfaced lumber Same as dressed lumber.

surface drying See skin drying.

surface flame spread The propagation of
flame across the surface of a material away from
its source of ignition; see flame spread index.

surface hardware preparation The rein-
forcement of a metal door or frame to receive
surface -mounted hardware which is applied after
the door is mounted.

surface hinge A hinge, often ornamental,
which is applied to the face of a door, as distin-
guished from one which is mounted on the edge
of a door.

surface latch A latch which is applied to the

face of a door.
surface measure See face measure, 1.

surface metal raceway A raceway which
consists of a surface-mounted assembly of metal
backing (providing mechanical support) and
capping (providing a protective covering); used
for electric wiring for branch circuits or feeder
conductors.

Base

detail of surface metal raceway

surface metal raceway: 90° bend

surface moisture, free water, surface
■water Water retained on surfaces of aggregate
particles and considered to be part of the mixing
water in concrete, as distinguished from
absorbed moisture within the permeable voids
of the aggregate particles.

surface-mounted astragal An astragal, 3

which is mounted on the surface of a pair of
doors along the joint between the meeting stiles.
(See illustration p . 970.)
surface-mounted luminaire A luminaire

that is mounted directly on the ceiling.

969

surface planer

surface-mounted astragal

surface planer A machine which is used to
dress or plane the surface of a material such as
metal, stone, or wood.

surface polishing The additional polishing of
plate glass necessary to remove slight defects.

surface retarder A retarder applied to the
surface of newly placed concrete or to form-
work; used to (a) delay setting of the cement,
(b) facilitate the production of exposed aggre-
gate finish, or (c) facilitate construction joint
cleanup.

surfacer 1. A paint containing a high percent-
age of pigment; used as an intermediate coat to
provide a smooth, uniform substrate for applica-
tion of finish coats. 2. A surface planer for tim-
ber. 3. A machine for polishing stone surfaces;
also called a dunter machine.

surface rib A decorative rib on the soffit of a
vault.

surface sash center A sash center designed
for surface mounting on the sash.

surface scaling See scaling.

surface sealer See sealer.

surface spread of flame See flame spread
index.

surface texture The degree of roughness of
the exterior surfaces of hardened concrete or of
aggregate particles.

surface void A cavity which is visible on the
surface of a solid.

surface water 1 . See surface moisture. 2. Rain-
fall which runs over the surface of the ground. 3.
Water carried by an aggregate except that held
by absorption within the aggregate particles
themselves.

surface-water drain A storm drain.

surface waterproofer See waterproofing.

surface wetting and adhesion The mutual
affinity of (and bonding between) a finish and
the surface to which it is applied.

surface wiring switch A switch mechanism
which is designed for mounting on a surface,
such as a wall, with all or almost all of the switch
body extending beyond the surface on which it
is mounted.

surface wiring switch

surfacing l.The material used as a protective
covering or coating as on the top side of a built-
up roof, a floor, an outdoor tennis court, etc.
2. In welding, same as cladding, 3.

surfacing weld A weld which consists of one
or more stringer beads or weave beads deposited
on an unbroken surface in order to establish
desired dimensions or properties.

surfactant A chemical wetting agent; added to
water to improve its penetration into a material;
often useful in reducing the amount of water
required in removing a material from the surface
on which it has been applied.

surform tool A cutting tool used for shaping
and trimming wood; shaped either like a large,
coarse, flat file or like a large, coarse, round file;
has hundreds of sharp cutting teeth, pitched at
an angle of about 45°, which take off wood like
a plane, the chips passing through holes in the
top of the tool.

surge A sudden voltage rise and/or fall in an
electrical current.

surge arrester A protective device that limits
surge currents through electrical equipment.

surge drum, surge header An accumu-
lator, 1 .

surge tank In a water-supply system, a reserve
tank which supplies some of the water when
there is a sudden drop in pressure, helping to
maintain a more uniform flow.

Surinam mahogany See carapa.

surmounted arch A semicircular stilted arch.

970

suspended ceiling

surround A decorative element or structure
around a doorway, fireplace, or window; for
example, see arch surround, banded surround,
door surround, fireplace surround, Gibbs sur-
round, window surround.

surround curtain In a theater, a curtain hung
in such a manner that it envelops an area of a
stage.

survey 1 . A boundary and/or topographic map-
ping of a site. 2. A compilation of the measure-
ments of an existing building. 3. An analysis of a
building for use of space. 4. A determination of
the owner's requirements for a project. 5. An
investigation and report of required data for a
project. 6. The process of determining data
relating to the physical or chemical characteris-
tics of the earth, such as a land survey or topo-
graphic survey.

surveying That branch of engineering con-
cerned with a determination of the earth's sur-
face features in relation to each other, as the
relative position of points, a determination of
areas, etc., and their recording on a map.

surveyor One whose occupation is surveying,
or who is otherwise skilled in the art.

surveyor's arrow See chaining pin.

surveyor's compass An instrument used by
surveyors for measuring horizontal angles and
for determining the magnetic bearing of a line
of sight; consists of a pivoted magnetic needle,
a graduated horizontal circle, and a sighting
device.

surveyor's level Same as level, 1.

surveyor's level

survey station Same as station, 1.

survey traverse In surveying, a sequence of
lengths and directions of lines between points
on the earth, obtained by or from field measure-
ments and used in determining positions of the
points.

suspended absorber A sound-absorptive ma-
terial, formed as a discrete structure; designed for
overhead suspension within a room.

suspended acoustical ceiling An acoustical
ceiling which is suspended from the building
structure above; usually the acoustical material
itself forms a suspended ceiling, but it also may
be secured to a backing.

suspended ceiling, dropped ceiling A non-
structural ceiling suspended below the overhead

surveyor s compass

suspended ceiling

971

suspended floor

structural slab or from the structural elements of

a building and not bearing on the walls.
suspended floor A floor which spans the

entire distance between end supports without

additional support in the middle.
suspended formwork Any formwork which

is supported on hangers.
suspended metal lath A system of metal lath

suspended by wire hangers from furring channels

and framing channels; the metal lath is used as a

base for a plaster ceiling.

suspended metal lath

suspended scaffold A scaffold consisting of a
number of outriggers, 2 from which wire ropes
are wound on hand-operated winches on the
scaffold platform.

suspended slab A concrete slab that spans the
space between columns, posts, or walls, in con-
trast to the concrete slab in a floating floor that
is mechanically isolated from, and supported by,
the structural slab.

suspended span A span, 3 which is supported
between two cantilevers.

suspended-type furnace A self-contained
warm-air furnace designed to be suspended from
the ceiling to supply heated air through ducts to
spaces other than the room in which the furnace
is located.

suspending agent A material, used in a paint to
improve its resistance to the settling of pigments.

suspension roof A roof whose load is carried
by a number of cables.

suspensura A horizontal slab which was raised
above ground level and supported by arches,
piles, or pillars so that it could be heated from
below, thereby providing for the possibility of
radiant heating; once used as flooring of ancient
Roman baths.

Sussex bond Same as Flemish garden wall
bond.

sustaining wall A structural wall, such as a
bearing wall or retaining wall.

SW On drawings, abbr. for switch.

swag A festoon.

swage 1. A tool or die used to shape metal. 2. A
tool for setting the teeth on a saw by bending
one tooth at a time to the proper angle. 3. To
shape metal by the use of a swage, 1 .

swage block A heavy block of iron or steel,
perforated with holes of different sizes and
shapes and variously grooved on the sides; used
to swage objects of larger size or to head bolts.

swage bolt, swedge bolt An anchor bolt, 1

whose shank has been deformed by swaging to

increase its resistance to being pulled out.
swage pile A pipe pile, having a thin wall; the

bottom of the pipe is closed with a precast point.
swale 1. A tract of low, usually wet land. 2. A

depression in a stretch of otherwise flat land.
swallow hole A term occasionally used as a

synonym for owl hole although swallow holes

are usually smaller.

swallow tail Same as dovetail.

swan»neck 1 . The curved portion of a handrail
of stairs which joins the newel-post. The mem-
ber's upper part is convex on the top; the lower
part is concave on the top. 2. A downspout con-
nector between a gutter and the downpipe,
where the eaves overhang.

swanneck chisel l.A long, curved mortise
chisel. 2. A corner chisel.

swan's-neck pediment A broken pediment
having a sloping double S-shaped decorative ele-
ment on each side of the pediment; said to be
suggestive of the necks of a pair of swans facing
each other.

sward Turf, or ground covered with turf.

swatch A representative patch or sample of
material, as a small piece of carpet or a sample
of veneer.

sway In thatched roof construction, one of the
small willow or hazelwood rods laid at right
angles to the thatching to hold it down.

sway brace Same as wind brace.

SWBD On drawings, abbr. for switchboard.

972

sweep tee

swan's-neck pediment

sweated joint A gastight, metal pipe joint
which is either soldered or brazed.

sweathouse, sweat lodge 1 . A structure used
for sweating of tobacco. 2. An American Indian
structure heated by steam produced by pouring
water on hot stones, and used for therapeutic
sweating or ritual.

sweating 1 . On a paint or varnish film, the
development of gloss on a dull or matte finish;
caused by rubbing the film. 2. The joining of
metal surfaces by heating and pressing them
together, usually with solder between. 3. The
collecting of moisture on a surface which is
below the dewpoint temperature, as a result of
condensation of moisture from the air. 4. See
surface condensation.

sweat-out A soft, damp area occurring in plas-
terwork; usually caused by insufficient ventila-
tion and very slow drying; plaster thus affected
does not develop good strength.

Sweet's Catalog A comprehensive series of
commercial catalogs of building materials and
equipment used in building technology; this
indexed reference source is organized according
to the 1 6 divisions illustrated under contract doc-
ument. Its Web site is www.sweetsconstruction.
com.

swedge Same as swage.

swedge bolt See swage bolt.

Swedish gambrel roof A roof having two flat
surfaces on each side of the central ridge of the

roof; similar to a New England gambrel roof or a
Dutch gambrel roof, except that the upper surface
is shorter and has little slope, and the lower sur-
face is longer and has a much steeper slope than
either the New England or Dutch gambrel roofs.

sweep 1 . Said of any large form or mass that
curves; for example, the sweep of a curved wall.
2. A long pole, pivoted on a vertical post, to
which a bucket is attached at one end; used to
raise water from a well.

sweep fitting Any fitting which has a large
radius of curvature.

- i

90° sweep fitting

sweep lock A sash fast, usually placed on the
meeting rails of a window to secure the window;
controlled by the action of a lever which rotates
to a position where it is secured by a catch.

sweep lock

sweep strip, door sweep A flexible weather
stripping used at the top and bottom edges of a
revolving door.

sweep tee A pipe tee in which each of the two
branches gradually curves away from the main
run of pipe instead of turning at a right angle.

973

sweet gum

sweet gum Same as gum, 1.

Sweitzer barn A Swiss barn; see German barn.

swellage See swelling.

swell box In a pipe organ, the chamber in
which the pipes of the swell organ are placed,
the front being made with movable slats which
can be opened or shut by means of a pedal.

swelled chamfer See wave molding.

swell factor Of a material such as soil, the ratio
of the weight of a loose cubic yard (or meter) to
the weight of a bank cubic yard (or meter).

swelling The volume increase caused by wetting,
absorption of moisture, or chemical changes.

swept valley On a roof, a valley formed of
shingles, slates, or tiles; "tile-and-a-half" units
are cut with a taper, eliminating the need for a
metal valley and giving the appearance of a con-
tinuous course.

S.W.G. Abbr. for Brit, standard wire gauge.

swift In prestressing, the reel or turntable on
which the tendons are placed for convenience in
handling and placement.

swimming pool Any basin or tank containing
an artificial body of water sufficiently deep for
swimming.

swimming pool paint Specially formulated
water-impermeable paint having good wet adhe-
sion; used to decorate and protect interior sur-
faces of swimming pools.

swing The action of a door's movement, usually
on hinges or pivots, about a hanging stile.

swing check valve A type of check valve
having a hinged gate which permits fluid to pass
through the valve only in one direction; esp.
used where fluid velocities are low.

ANGLE
PLUG

DISK NUT

HINGE
' PIN

swinging door See double-acting door.

swinging latch bolt A latch bolt that is
hinged to a lock front and is retracted with a
swinging rather than a sliding action.

swinging post See hanging post.

swinging scaffold, swinging stage A scaf-
fold which is suspended by ropes or cables from a
block and tackle attached by roof hooks; can be
raised or lowered to any height.

GUARDRAIL

swinging scaffold

swing joint A type of joint used with threaded
pipe which permits motion to occur when
the pipes are heated or cooled, without bending
of the pipes; esp. used in riser and radiator
connections.

ARM DISK

swing check valve

swing joint

974

swivel spindle

swing loader A tractor loader which digs at it
its front end, but which may dump its load on
the side of the tractor.

swing leaf 1. An active leaf in a double door.
2. A hinged sash (ventilator, 2) in a casement
window.

swing offset In surveying, the perpendicular
distance from a point to a survey line found by
swinging a tape about the point as a center and
measuring the minimum distance from the point
to the line.

Swiss Cottage architecture

TRANSIT
LINE

SWING OFFSET

swing offset

swing saw, pendulum saw A power-oper-
ated circular saw suspended from above and piv-
oted on a long arm.

swing scaffold, swing stage Same as swing-
ing scaffold.

swing-up door Same as swing-up garage door.

swing-up garage door A rigid overhead door
which opens as an entire unit.

swipe card reader A security device for pro-
viding access to a locked door. The person seek-
ing entry is required to move a card (having a
coated magnetic strip on one side) rapidly
through an open-ended slot.

swirl The irregular wood grain pattern that sur-
rounds knots or crotches, esp. found in veneer.

swirl finish A nonskid texture imparted to a
concrete surface during final troweling by keep-
ing the trowel flat and using a rotary motion.

Swiss barn See German barn.

Swiss Cottage architecture, Swiss Chalet
architecture A domestic picturesque archi-
tecture patterned after its chalet prototype in

Switzerland; usually a two-story house built of
rough-cut lumber to enhance its rustic appear-
ance; often a front-gabled, shingled roof of mod-
erate pitch, occasionally a jerkinhead roof;
bracketed eaves having a significant overhang;
exposed rafters; often, walls of board-and-batten
construction; porches typically have flat balus-
ters with cut-outs or stickwork. Occasionally
called Swiss Cottage style or Chalet Gothic.

switch A device used to open or close an elec-
tric circuit or to change the connection of a cir-
cuit.

switchboard A large single electric control
panel, frame, or assembly of panels on which
are mounted (either on the back or on the
face, or both) switches, overcurrent and other
protective devices, buses, and usually instru-
ments; not intended for installation in a cabi-
net but may be completely enclosed in metal;
usually is accessible from both the front and
rear.

switchgear Any switching and interrupting
devices in combination with their associated
control, regulating, metering, and protective
devices.

switch mat A floor mat containing thin metal
blades laminated in plastic sheets. When an
intruder steps on the mat, the blades make con-
tact and an alarm is activated.

switch plate A flush plate for an electric switch.

switch-start fluorescent lamp See preheat
fluorescent lamp.

swivel joint Same as swing joint.

swivel spindle In door hardware, a spindle, 1
having a joint midway along its length which per-
mits the knob at one end to be held fixed by the
stop works, while the other end is free to operate.

975

swp

swp Abbr. for "steam working pressure."

sycamore A tough, yellowish wood having a
close, firm texture; takes a fine polish; used for
flooring and veneer.

SYM On drawings, abbr. for "symmetrical."

Symmetrical Victorian style A term once
occasionally used to describe a style of Ginger-
bread Folk architecture.

SYN On drawings, abbr. for "synthetic."

Synadicum marble Same as pavonazzo, 2.

synagogue A place of assembly for Jewish wor-
ship.

synchronous motor A motor which rotates
at a constant speed, at a number of revolutions
equal to the frequency of the supply voltage
divided by one -half its number of poles or wind-
ings.

synergizing agent In water conditioning, a
substance which increases the effectiveness of a
scale or corrosion inhibitor.

synodal hall A hall in which the clergy of a
whole diocese meet.

synthetic paint A paint made with syntheti-
cally manufactured resins rather than with natu-
rally occurring oils or gums.

synthetic resin Any of a large number of
resin-like products made either by polymeriza-
tion or condensation, or by modifying a natural
material.

synthetic rubber An elastomer manufactured
by a chemical process, as distinguished from nat-
ural rubber obtained from trees; rubberlike with
respect to its degree of elasticity.

synthetic rubber-base paint Same as latex
paint.

synthetic silica Same as silica gel.

synthetic stone Same as artificial stone.

Syrian arch On a classical facade, an arched
entablature over the central intercolumniation.

Syrian arch

syrinx In ancient Egypt, a narrow and deep
rock-cut channel or tunnel forming a character-
istic feature of Egyptian tombs of the New
Empire.

SYS On drawings, abbr. for "system."

system In building construction, prefabricated
assemblies, components, and parts which are
combined into single integrated units utilizing
industrialized production techniques.

Systeme International d'Unites See Inter-
national System of Units.

system riser In a fire sprinkler system, the
aboveground supply pipe which is directly con-
nected to the water supply.

systems building See prefabricated construc-
tion and industrialized building.

systyle See intercolumniation.

976

T On drawings, abbr. for tee.
T&G Abbr. for tongue-and-groove.
T&G joint See tongue-and-groove joint.

tab 1. A small, narrow drop curtain in a theater

used to mask from view a portion of the stage. 2.

A tableau curtain. 3. The lower end of a shingle;

the visible portion of a roof shingle that remains

uncovered.
tabby A mixture of lime and water with shells,

gravel, or stones; when dry, forms a mass as hard

as rock; used as a building material.
taberna In ancient Rome, a booth, shop, or stall.
tabernacle 1 . A decorative niche often topped

with a canopy and housing a statue. 2. A church

for a large Protestant congregation.

tabernacle, 1

tabernacle frame The frame for a door, win-
dow, or other opening that is treated as part of a
complete design with columns or pilasters and
an entablature.

tabernacle work A highly decorated arcade
with canopies and sculpture.

tabia A rammed earth mixed with lime and
pebbles.

tabla house A primitive one-room house of
wood-frame construction sheathed with vertical
cypress rough-hewn planks (tablets), used by early
Spanish colonists in Florida in the 16th century.
Typically, had a gable roof thatched with palm
leaves, a hole in the roof at the ridge to permit
smoke to escape from the fireplace below, and a
battened door.

tablas In Hispanic architecture and derivatives,
long, square-sawn timbers.

tablature 1. A tabular surface or structure. 2. A
painting or design on a part of an extended sur-
face, as a ceiling.

table 1. A stringcourse or other horizontal band
of some size and weight; a horizontal molding on
the exterior or interior face of a wall. 2. A flat
surface fomring a distinct feature in a wall, gener-
ally rectangular and ornamented. 3. In medieval
architecture, the frontal on the face of the altar.
4. A slab set horizontally and carried on supports.

table, 2

table- base Same as base molding, 2.

tableau curtain A curtain on the stage of a
theater which pulls back as it rises, creating a
single festoon on each side, giving a draped
effect; may function as the act curtain.

977

tabled joint

tabled joint In cut stonework, a bed joint
formed by a broad, shallow channel in the sur-
face of one stone which fits a corresponding pro-
jection of the stone above or below.

table saw A circular saw which is set below the
surface of a table having a slot through which
the saw blade protrudes.

table stone Same as dolmen.

tablet 1. A regularly shaped, separate panel, or a
representation thereof, often bearing an inscrip-
tion or image. 2. A coping stone, set flat; also
called tabling. 3. A plaque, often inscribed and
carved, usually affixed to a wall surface or set
into the surface; sometimes used to serve as a
memorial or to commemorate a special event.

tablet flower In Decorated Gothic architec-
ture, a variation of the ballflower, having the
form of an open flower with four petals.

tabling Same as tablet, 2.

tablinum In ancient Roman architecture, a
large open room or apartment for family records
and hereditary statues; situated at the end of the
atrium farthest from the main entrance.

tabularium See archivium.

tacheometer See tachymeter.

tachometer See tachymeter.

tachymeter, tacheometer, tachometer A

surveying instrument designed for use in the
rapid determination of distance, direction, and
difference of elevation from a single observation,
using a short base which may be an integral part
of the instrument.
tack 1 . A strip of metal, usually lead or copper,
used as a clip to secure the edges of metal items in
roof construction, such as flashings. 2. A short,
sharp-pointed nail. 3. The property of an adhe-
sive that enables it to form a bond of measurable
strength immediately after the adhesive and
adherend are brought into contact under low
pressure. 4. To glue, weld, or otherwise fasten in
spots rather than in a continuous line.

tack coat See asphalt tack coat.

tack dry Descriptive of the stage in the drying

of an adhesive at which it will adhere to itself on

contact, although it seems dry to the touch.
tack-free dry Descriptive of the stage in the

drying of a paint or varnish film at which it no

longer feels sticky to the touch.

tack»free time The time period during which
a sealant that is molded in the field remains
tacky and is not yet fully serviceable.

tackle A mechanism for shifting, raising, or lower-
ing objects or materials, such as a rope and pulley
block or an assembly of ropes and pulley blocks.

tackle

tackless strip A metal strip, beneath the edge
of carpeting, which is fastened to the floor, to a
stair, etc.; the strip has many small hooks which
point upward and slightly toward the edge; the
carpeting is stretched beyond the metal strip,
allowing the hooks to secure the carpet backing
and hold the carpeting in place.

UNDERLAY

tackless strip

tack rag A rag impregnated with a slow-drying
or nondrying varnish or resin; used to wipe dust,
lint, and dirt from an article before it is painted.

tack range The period of time during which an
adhesive remains in the tacky dry condition
after application to an adherend.

978

take-up block

tack rivet A rivet, usually temporary, to hold
work during riveting; not intended as a load-
carrying rivet.

tack room A room for holding bridles, saddles,

and harnesses; usually in a stable.
tack strip A variant term for tackless strip.

tack weld 1 . A weld used for holding metal parts
in position temporarily. 2. One of a series of welds
applied where a continuous weld is unnecessary.

tacky dry, tacky 1 . That stage in the drying of
an adhesive at which the volatile constituents
have evaporated or been absorbed sufficiently so
as to leave the adhesive in a desired condition of
tackiness. 2. That stage in the drying of a paint
at which the film appears sticky when lightly
touched with the finger.

taenia, tenia A narrow raised band or fillet,
particularly the topmost member of the Doric
architrave. Also see order.

Cymatiaift

Taenia -C

framed floor or roof, a bay, 1 which is next to the
end wall; one end of its joists rests on the end
wall, the other on a girder.

tail beam See tail piece, 1.

tail cut l.A cut in the lower end of a rafter
where it overhangs the wall; sometimes ornamen-
tal. 2. The seat cut at the lower end of a rafter.

tailing l.That portion of a projecting stone or
series of stones, as in a cornice, which is built
into a wall. 2. See tailings.

tailing in 1. Securing one end or edge of a pro-
jecting masonry unit, as a cornice. 2. To fasten
one end of a timber, as a floor joist at a wall.

tailing iron A steel member, built into a wall,
to take the upward thrust of a cantilevered mem-
ber, directly below it, projecting from the wall.

tailings 1. Stones which do not pass through
the largest openings of a screen used to separate
sizes (as after a crushing operation). 2. The
residue or leavings of any product.

tail joist See tailpiece, 1.

tailpiece l.A short beam, joist, or rafter, which is
supported by a header joist at one end and a wall at
the other; also called a tail beam or tail joist. 2. An
extension to centering, where there is a projection
from an impost; can be removed easily. 3. A look-
out. 4. A pipe tee used with a sink drain.

tafy joint A connection between two sections
of lead pipe; the straight spigot end of one sec-
tion is inserted in the flared-out end of the
adjoining section; the joint is then sealed with
solder.

tag l.In roofing, a sheet-metal strip which is
folded over and used as a wedge for holding
metallic sheeting in a masonry joint. 2. A tem-
porary sign, usually attached to a piece of equip-
ment or part of a structure, to warn of existing or
potential hazards.

tagger A sheet of tinplate, or the like, which is
of less than standard thickness.

t'ai Chinese tower structure, rectangular in plan
with several receding stories. Watchtower in the
Han period; earlier, a hunting or pleasure tower.

tail 1. Exposed lower portion of a slate shingle.
2. Tailing. 3. See rafter tail. 4. See lookout.

tail bay 1. In a framed floor, the space between
a wall and the nearest girder of the floor. 2. In a

HEADER

TAILPIECE

tailpiece, 1

tail trimmer A trimmer placed next to a wall,
into which the ends of the joists are fastened
instead of supporting them on the wall.

takeoff Same as quantity survey.

take-up Any device or mechanism for taking
up slack.

take-up block A guided pulley block, rigged
so that its weight or spring loading prevents
slack from occurring in lines passing through it.

979

taking

taking Of property, a government action that
substantially disturbs or interferes with an
owner's use and enjoyment of the property.

T&P valve See temperature and pressure
relief valve.

takspan A Swedish pine shingle for roofing.

talc A soft mineral composed of hydrous magne-
sium silicate; a major ingredient of soapstone;
used on roll roofing to prevent sticking in the roll.

tallboy A chimney pot of long and slender
form, intended to improve the draft.

tallus See talus.

tallut, tallet, tallot (Brit. ) A loft or attic.

talon molding An ogee, 2.

talus, tallus l.The slope or inclination of any
work, as a talus wall. 2. Coarse rock fragments,
mixed with soil, at the foot of a cliff or natural
slope.

talus wall A wall having an inclined face; a
battered wall.

tamarack See larch.

tambour l.A column drum. 2. Any generally
drum-shaped member.

tamo See Japanese ash.

tamp To compact a material or surface, such as
earth or freshly placed concrete, by repeated
blows.

tamper A compaction device for consolidating
a granular material such as soil, backfill, or
unformed concrete; usually powered by a motor.
Also see jitterbug.

tamper

tamping rod A straight steel rod, having a
rounded tip at one end.

tamping roller See sheepsfoot roller.

tampion A cone-shaped hardwood tool used by
plumbers; forced into the end of a lead pipe to
increase its diameter.

T and G Abbr. for tongue and groove.

tanalized lumber Sometimes said of lumber
that has been treated with a preservative.

tang The slender projecting tongue, or prong,
forming part of one object that serves to secure it
to another, as the projecting tongue on a chisel
that secures it to a handle.

tang

tangent Of lines, curves, and surfaces: meeting
at a single point and having, at that point, the
same direction.

tangential flow filtration Same as crossflow
filtration.

tangential shrinkage The shrinkage across
the width of plain-sawn lumber.

tangential stress A shear stress.
tangent-sawn Same as plain-sawn.

tanguile, tangile A hardwood which resembles
true mahogany, but shrinks and swells to a greater
extent when exposed to moisture; the sapwood is
light red, and the heartwood is brownish red.

tanking (Brit.) A waterproof lining for a base-
ment floor and walls.

tankless heater A hot-water heater having a
metal coil, through which an electric current flows,
which is immersed in a boiler; especially used in
homes. Also see instantaneous-type water heater.

tap l.A connection to a water supply main. 2.
A faucet. 3. A tool used for cutting internal
threads, as in a pipe.

tap bolt A machine bolt, threaded relatively
close to the head, which is screwed into a hole in
a material without the use of a nut.

tap bolt

tap borer A hand tool used by plumbers for
boring tapered holes, as in a lead pipe when
making a connection to it.

980

tapping machine

tape 1. See joint tape. 2. See taping strip.
3. See tape measure. 4. See friction tape.
5. See thermoplastic insulating tape. 6. See ther-
moplastic protective tape.

tape balance A sash balance in which the weight
of the sash is counterbalanced by the force supplied
by a metal tape coiled on a spring-loaded reel.

tape correction A correction applied to a dis-
tance measured with a tape to eliminate errors
caused by the physical condition of the tape or
by the way the tape was used.

tapeista In Spanish Colonial architecture, a
crude rooflike structure supported by four posts;
used as a somewhat protected open-storage area
for cornstalks, hay, or the like; also see jacal, 1.

tape joint A flat joint, sealed with a joint com-
pound and covered with a reinforcing tape
which provides added strength.

tape measure, tapeline A steel ribbon used
for the measurement of distances; in the US,
surveyor's and engineer's tapes usually are accu-
rately graduated in feet, tenths, and hundredths
of a foot; builder's tapes are graduated in feet,
inches, and fractions of an inch; also called a
steel measuring tape.

©lEE^

tape measure

taper A gradual diminution of thickness in an
elongated object, as in a spire.

tapered edge strip In built-up roofing, a
tapered strip of insulation used to raise the roof-
ing at its perimeter, where there are penetrations
through the roofing.

tapered-roll pantile A roofing pantile having
a roll that has a slight increase in width from the
head to the tail of the tile.

tapered tenon A tenon which decreases in
width from the root toward the end.

tapered tread The horizontal surface of a step
that is wider at the outer end than at the inner
end, as in a spiral stair.

tapered valley In roofing, a valley, formed
between shingles, slates, or tiles, which is wider
at the bottom than the top.

taper pin A headless , solid pin having controlled
diameter, length, and taper, with crowned ends.

taper pin

taper pipe See diminishing pipe.

taper thread A screw thread which is formed
on a cone or the frustum of a cone; used on some
types of fasteners; used in plumbing on pipes and
fittings, 1 to ensure a gastight joint.

tapestry A fabric, worked on a warp by hand,
the designs employed usually being pictorial;
used for wall hangings or the like.

tapestry brick Same as rustic brick.

tapia An adobe-like building material consist-
ing mainly of earth or clay in which small peb-
bles was imbedded; this term is also occasionally
applied to puddled adobe.

taping Measuring distance on the ground with a
tape or chain.

taping arrow See chaining pin.

taping compound A compound that is specifi-
cally formulated and manufactured for embedding
a joint reinforcing tape at a gypsum board joint.

taping pin See chaining pin.

taping strip 1. A strip of roofing felt laid over
the joints between adjacent precast concrete
roof slabs; prevents bitumen which is applied
subsequently from dripping into the space below.
2. A strip used to cover the joint between adja-
cent roof insulation boards.

tapped fitting Any pipe fitting, 1 having a
tapped internal thread to receive a threaded
pipe.

tapped tee In plumbing, a bell-end tee which
has a branch that is tapped to receive a threaded
pipe fitting or a threaded pipe.

tapping machine A machine designed to pro-
duce a sequence of uniform impacts on a floor
surface; used to measure impact sound transmis-
sion of a floor-ceiling assembly.

981

tapping screw

tapping screw See sheet-metal screw.

tapping screw

tar See coal-tar pitch.

tar-and-gravel roofing A built-up roofing

which has a surfacing material consisting of
gravel in a heavy coat of coal-tar pitch.
tar cement Heavier grades of asphalt cement
which are prepared for direct use in construction
and maintenance of bituminous pavements.

tar concrete See asphaltic concrete.

target In surveying, see leveling rod.

target leveling rod A type of leveling rod car-
rying a target, which is moved into position
according to signals given by the instrument
man; when the target is bisected by the line of
collimation of the instrument, it is read and
recorded by the rod man.

target rod See leveling rod.

tarmac, tarmacadam See macadam.

tarnish An oxide layer on a metal surface that
causes it to dull, often discoloring it.

tar paper See asphalt prepared roofing.

tarpaulin A waterproof cloth, esp. one used in
large sheets for covering anything exposed to the
weather.

tarred felt Same as asphaltic felt.
tarsia Same as inlay.

tas»de-charge l.The lowest voussoir or vous-
soirs of an arch or vault with the joints horizon-
tal instead of radial. 2. In vaulting, that section
of a group of vault ribs between the line where
they spring and the line where they separate.

task lighting Lighting that is directed to a spe-
cific area to provide illumination for the perfor-
mance of a visual task.

tasolera In Spanish Colonial architecture, a barn
to house animals or to store agricultural produce.

tatami A thick straw mat serving as floor cover-
ing in the Japanese house. Used as standard unit
of floor area, approx. 3 ft by 6 ft (1 m by 2 m).

tauriform See bull's head.

tavern See inn, 1.

tax abatement The reduction of real estate
taxes on a property; usually accomplished by
means of a reduction in its assessed value.

taxamanil Thatched roofing.

tax exemption The release of a property from
the obligation to pay real estate taxes.

taxpayer A building, often temporary, which
yields a minimal return on investment, usually
little more than real estate taxes.

TB Abbr. for through bolt.

T»bar In a perforated-metal-pan acoustical ceiling
assembly, a metal suspension member designed to
support the metal pan by engaging its flanges.

T»beam A reinforced concrete beam or rolled
metal shape having a cross section resembling
the letter T

FLANGE

STEM

T-be

T»bevel Same as bevel square.

TC On drawings, abbr. for terra-cotta.

tchahar taq Square open pavilion in Sassanian
architecture (a.D. 224-651), composed of four
columns with four arches supporting a dome,
mostly over an altar.

tea garden 1. A Japanese garden next to a tea-
house, usually small and serene. 2. An outdoor
tearoom in a public garden, serving refresh-
ments, including tea.

teagle A hoist.

teagle post In timber framing, a post support-
ing one end of a tie beam.

teahouse A Japanese garden house used for
the tea ceremony.

teak A dark golden yellow or brown wood with
a greenish or black cast, found in southeastern
Asia, India, and Burma; moderately hard,
coarse-grained, very durable; oil which it con-
tains gives it a greasy feeling and makes it
immune to the attack of insects; used for exterior
construction, plywood, and decorative paneling;
also called Indian oak.

982

telephone booth

tear See run, 5.

tearing A defect in the surface of porcelain
enamel, characterized by crackle or short breaks
which have been healed.

tear strength A material's resistance against
being pulled apart.

tease To work out a surface defect, as on a var-
nished surface.

teaser A horizontal curtain or canvas-covered
framework, behind and across the top of the
proscenium arch of a theater; used to conceal
the flies and, together with the tormentors along
the sides, to frame the opening of the stage.

tease tenon See teaze tenon.

teaze tenon, tease tenon A tenon, having a
stepped outline, on the top of a post; esp. cut to
receive two horizontal pieces of timber that cross
each other (at right angles) at the post.

tebam The reader's platform in a synagogue.

tectiform Like a roof in form or use.

tectonic Of or pertaining to building or con-
struction; architectural.

tectorial Covering, forming a roof-like structure.

tectorium opus See opus tectorium.

tee 1 . A finial in the form of a conventionalized
umbrella, used on stupas, topes, and pagodas. 2.
Same as pipe tee. 3. A metal member having a
constant T-shaped cross section.

tee, 1:

s the finial of a pagoda

tee beam See T-beam.

tee bevel Same as bevel square.

tee handle A T-shaped handle for actuating the
bolt of a lock on a door; used in place of a knob.
tee head See T-head.
tee hinge See T-hinge.

tee iron 1 . A flat T-shaped piece of heavy sheet
metal having predrilled, countersunk holes;
screwed to a joint in wood construction in order
to provide reinforcement. 2. A section of steel
T-beam.

tee joint A joint between two members which
are located approximately at right angles to each
other in the form of the letter T

tee, 2: copper-to-copper pipe tee

welded tee joint

teepee Same as tipi.
tee square See T-square.

Teflon The proprietary name for polytetra-

fluoroethylene .

tegula A tile, esp. one of unusual shape or
material.

tegular Relating to, or arranged like, a tile.

tegurium A roof over a sarcophagus, usually
double-sloped and supported by narrow columns.

teja In Spanish Colonial architecture, a burnt-
clay roof tile, semicircular in cross section, and
usually tapered.

TEL On drawings, abbr. for "telephone."

telamon (pi. telamones) A sculptured male
human figure used in place of a column to sup-
port an entablature; also called an atlas. (See
illustration p . 984.)

telecommunications The transmission and
reception of signals (such as electrical or optical)
by wire, optical fiber, or electromagnetic means.

telegraphing, show-through On a decora-
tive material covering a wall, etc., irregularities,
imperfections, or patterns of an inner layer
which are transmitted to the surface so that they
become visible.

telephone booth An enclosure for a telephone
in a public area.

983

telephone station

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telamones at Agrigentum

telephone station A shelf unit for a telephone
in a public area.

telescope house A house comprised of several
units, each of descending height, giving the
building the appearance of fitting together like
the components of a collapsible telescope; com-
pare with continuous house.

telltale Any device designed to indicate move-
ment of formwork.

temenos A sacred enclosure surrounding a
temple or other holy spot.

TEMP On drawings, abbr. for "temperature."

temper l.To mix lime, sand, and water in
such proportions as to make mortar for masonry
or plastering. 2. To moisten and mix clay to
proper consistency to form bricks, etc., prior to
hardening by fire. 3. To bring to a proper degree
of hardness and elasticity for use, as steel or
other metal, by heat treatment. 4. To impreg-
nate wood fibers or composition board with a
drying oil or other oxidizing resin and subse-
quently to cure with heat so as to improve the
strength, hardness, water resistance, and dura-
bility of the board.

tempera A rapidly drying paint consisting of
egg white (or egg yolk, or a mixture of egg white
and yolk), gum, pigment, and water; esp. used in
painting murals.

temperature and pressure relief valve

A valve that combines the functions of a pres-
sure relief valve and a temperature relief valve.
temperature controller See thermostat.

temperature cracking The cracking of a
concrete member due to tensile failure caused by
a temperature drop (if member is subjected to
external restraints) or caused by a temperature
differential (if member is subjected to internal
restraints).

temperature reinforcement In reinforced
concrete, reinforcement that is designed to
resist tensile stresses resulting from changes in
temperature.

temperature relay A relay that operates at a
predetermined temperature in the apparatus
which it protects.

temperature relief valve A temperature-
actuated safety valve designed to open automat-
ically when the temperature of the water being
heated exceeds a preset value.

temperature rise In cement, the increase in
temperature resulting from the absorption of
heat or from the internally generated heat, as by
the hydration of cement in concrete.

temperature steel Steel reinforcement which
is placed in a concrete slab, or the like, to mini-
mize the possibility of developing cracks as a
result of temperature changes.

temperature stress See thermal stress.

temperature stress rod In reinforced con-
crete, one of a number of steel rods laid perpen-
dicular to the reinforcing bars or rods to prevent
cracks from forming parallel to the reinforce-
ment, as a result of stresses from drying or from
thermal stresses; a type of temperature rein-
forcement.

tempered board A durable wood fiber or com-
position board; also see temper, 4.

tempered glass (US), toughened glass (Brit.)
Glass having two to five times the strength of ordi-
nary glass as a result of having been prestressed by
heating and then suddenly quenched; the rapid
cooling produces a compressively-stressed surface
layer.

tempered steel Steel that has been heated to a
high temperature and then quenched, usually a

984

tenon

number of times, a process that significantly
hardens it; also called case-hardened steel.

tempered water Water in the temperature
range from 85°F (29°C) to 110°F (43°C).

tempietto A small temple, especially one of
ornamental character, during the Renaissance
or later; many such structures were con-
structed in the gardens of imposing country
houses.

template, templet l.A pattern, usually of
sheet material, used as a guide for setting out
work and in repeating dimensions. 2. A piece of
stone, metal, or timber placed in a wall to
receive the impost of a beam, girders, etc., and to
distribute its load. 3. A beam or plate spanning a
door or window space to sustain joists and trans-
fer their load to piers. 4. One of the wedges in a
building block.

template hardware Hardware that exactly
matches a master template drawing, as to spac-
ing of all holes and dimensions.

temple 1. An impressive edifice for a particular
public use. 2. A Classical edifice dedicated to the
service of an ancient deity, usually connected with
a system of worship. 3. A structure specifically
used for worship, for example, a synagogue or a
Buddhist temple.

temple, 1 : at Agrigentum

templet Same as template.

temple tower A ziggurat.

templon A trabeated colonnade which closes
off the bema of a Byzantine church.

temporary (electrical) service Electrical
service used for a limited time during construc-
tion, exhibits, or similar temporary purposes.

temporary shoring Shoring installed during
construction, to support a member or a portion
of the structure; removed prior to the comple-
tion of construction.

temporary stress In a precast concrete mem-
ber or in a component thereof, a stress which
may occur during fabrication, erection, con-
struction, or test loading.

temse Same as screen, 3.

tenancy Occupation by one with less than a fee
interest in property, e.g., a tenancy for life, or a
tenancy for a term of years. The latter type of
tenancy usually is created by lease.

tenancy in common Ownership of property
by two or more persons, each of whom may
freely transfer his interest; the death of one ten-
ant does not transfer his rights to the other or
others.

tenant A person or firm using a building, or part
of a building, as a lessee or owner-occupant.

tenant's improvement Improvements on real
property made by a tenant at his own expense.
Unless otherwise agreed, they become part of the
property and may not be removed by the tenant
at the end of his term.

tender A proposal or bid for a contract to per-
form work, often on a form, completed by a con-
tractor, giving estimated price and time to
complete a contract.

tendon In prestressed concrete, a steel element
such as a wire, cable, bar, rod, or strand used to
impart prestress to the concrete when the ele-
ment is placed under tension.

tendon profile In prestressed concrete, the
trajectory of a prestressing tendon.

tenement A building having multiple housing
units for rent; often, ill-maintained, over-
crowded units that may barely meet minimum
code requirements for safety and sanitation; usu-
ally built many years earlier and found in poorer
sections of a city.

tenia See taenia.

tenon The projecting end of a piece of wood, or
other material, which is reduced in cross section,

985

tenon-and-slot mortise

so that it may be inserted in a corresponding cav-
ity (mortise) in another piece in order to form a
secure joint. Also see mortise-and-tenon joint.

tenon-and-slot mortise A wood joint formed
by a tenon and a slot mortise, usually at right
angles to each other.

tenon saw A saw having a metal strip along the
back to stiffen it; has many small teeth; used for
fine, accurate sawing, as in forming tenons,
dovetails, and miters. Also called a miter saw.

tenon saw

tensile-frame construction See bent-frame

construction.
tensile modulus The ratio of the tensile stress

to the tensile strain over the range for which this

ratio is constant.

tensile strain The elongation of a material
which is subject to tension.

tensile strength The resistance of a material to
rupture when subject to tension; the maximum
tensile stress which the material can sustain.

tensile stress The stress per square unit area of
the original cross section of a material which
resists its elongation.

tension The state or condition of being pulled
or stretched.

tension bar A metal bar by means of which a

tensile strain is applied or resisted.
tension failure See primary tension failure.

tension member A structural member sub-
jected to tension; a tie.

tension pile Same as anchor pile.

tension reinforcement Reinforcement de-
signed to carry tensile stresses such as those in
the bottom of a simple beam.

tension ring A circular structural element
intended to resist the outward thrust of a dome.

tension rod A rod in a truss or structure which
connects opposite parts and prevents them from
spreading.

tension 'wood Abnormal wood found on the
upper side of hardwood branches and leaning
trunks; characterized by abnormally high longi-
tudinal shrinking, causing warping and splitting.

tent ceiling See comb ceiling.

tepee Same as tipi.

tepidarium In ancient Roman baths, a room of
moderately warm temperature.

TER On drawings, abbr. for terrazzo.

term Same as terminal figure.

terminal l.An electrically conductive ele-
ment, attached to the end of a conductor or
piece of equipment for connection to an exter-
nal conductor. 2. The ornamental finish, deco-
rative element, or termination of an object, item
of construction, or structural part.

terminal box On a piece of electric equipment
(such as a motor), a box within which the leads
from the piece of equipment are connected to
the leads supplying the equipment with power;
usually provided with a removable cover plate
for access.

terminal expense An expense incurred in
connection with the termination of a contract.

terminal figure, terminal statue A decora-
tive figure in which a head, or a head and bust,
or the human figure to the waist and including
the arms, is incorporated with (as if it were
springing out of) a pillar which serves as its
pedestal.

terminal pedestal A pedestal prepared for a
bust, so that the two together comprise a termi-
nal figure.

terminal reheat system An air-conditioning
system in which a reheat coil is provided for
each individually controlled zone, regulating the
temperature of the air being furnished.

986

termite shield

terminal pedestal

terminal stopping device A limit switch for

an elevator car.

terminal unit In an air-conditioning system, a
unit at the end of a branch duct through which
air is transferred or delivered to the conditioned
space.

terminal velocity In an air-conditioning sys-
tem, the average velocity of an airstream at the
end of its throw; one of the indicators of drafty
conditions and comfort level.

terminal window In a church, a window that
is at the end of an aisle or transept.

terminated stop, hospital stop, sanitary
stop A stop, 1 that terminates above the floor
line and is closed with a 45° or 90° angle.

terminating enclosure A type of enclosure
(approved by the utility company) which is
installed at the point of service for the load-end
termination of the utility company's service
cables where they join the customer's service
entrance conductors; includes concrete subway-
type pull boxes, manholes, wall-mounted pull
boxes, and switchboard pull sections.

terminating facility Any type of electrical
terminating enclosure or transformer enclosure.

termination An ornamental element which
finishes off an architectural feature such as
a dripstone.

terminus A bust or figure of the upper part of
the human body terminated in a plain block of
rectangular form; a terminal figure.

(a) Norman

(b) Early English style

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termite shield A shield of noncorroding metal
or inorganic material, used as protection against
the infiltration of termites in a building; so placed
as to prevent their passage, usually as a projecting
shield on a masonry foundation or pier (or under
a wood sill or beam which it supports), or around
pipes which enter the building.

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FLOOR JOIST

termite shield

987

terne metal

terne metal An alloy of lead, containing up to
20% tin.

terneplate Sheet steel which is coated with
terne metal; widely used for roofing and con-
struction work.

terra alba A pure white uncalcined gypsum
which is used as a filler in paints.

terrace l.An embankment with level top,
often paved, planted, and adorned for leisure
use. 2. A flat roof or a raised space or platform
adjoining a building, paved or planted, esp. one
used for leisure enjoyment.

terrace door A glass door which has one leaf
fixed and the other leaf hinged to the fixed leaf.

terrace house One of a row of houses situated
on a terrace, or similar site.

terrace roof See cut roof.

terra-cotta Clay that has been molded in shape
and then treated in a kiln at a high temperature;
typically reddish-brown in color when unglazed;
when glazed, usually colored and used for orna-
mental work, such as architectural terra-cotta,
and for floor tile and roof tile.

terrado In Hispanic architecture, a flat roof
made of compacted earth that is sealed with a
layer of plaster.

terras Same as trass.

terrazzo, terrazzo concrete Marble-aggregate
concrete that is cast in place or precast and
ground smooth; used as a decorative surfacing on
floors and walls.

terreplein An earth embankment, flattened at
the top.

Territorial Revival An architectural mode
of limited popularity in the southwestern
United States, particularly New Mexico, after
about 1920; basically a modification of Territo-
rial style.

Territorial style An architectural style in New
Mexico from the time it became a territory of the
United States in 1848 until about 1900; typi-
cally, a one-story house usually having a flat roof
with parapets, exterior walls of adobe coated with
adobe plaster or stucco; an entry door commonly
flanked with sidelights; brick trim around doors
and windows with pedimented lintels above,
sometimes with wood decorative trim suggestive
of the Greek Revival style. Such houses were
sometimes built around an enclosed courtyard

with rooms opening onto a covered walkway
around the perimeter of the courtyard.

terrone A building material cut into rect-
angular units of sod from a river bottom or
swamp, and then sun-baked; similar to adobe
but stronger when dry because of the added
strength provided by the sod roots; used in the
form of building blocks.

tertiary beam Any beam which transfers its
load to a secondary beam, at either one end or
both ends.

tessellated Formed of small square pieces of
marble, stone, glass, or the like, in the manner
of an ornamental mosaic.

tessellated 'work Inlay work composed of
tesserae.

tessera A small squarish piece of colored mar-
ble, glass, or tile, used to make mosaic patterns,
either geometric or figurative.

tesserae: shown separately and combined in a mosaic

tesseris structum Same as opus tessellatum.

test A check on the performance characteristics
of a building component, device, material, piece
of equipment, or system to determine its confor-
mity with performance criteria and standards.
Tests may be performed in the prototype stage,
during manufacture, at the site during and after
installation, after the project's completion, or at
any combination of these times.

testaceum Same as opus testaceum.

test code A measurement standard that is pri-
marily applicable to a specific class or type of
machinery or equipment.

test cylinder A cylinder of concrete 6 in. ( 1 5 cm )
in diameter and 12 in. (30 cm) high; cast from a
representative sample of the plastic concrete in any
pour and cured under controlled conditions; used

988

textile

to determine its compressive strength after a speci-
fied time interval.

tester 1. A flat canopy, as over a bed, throne, pul-
pit, or tomb. 2. In a church, the same as sounding
board.

testing machine Any device or machine used
to measure accurately the properties of a mate-
rial, product, assembly, etc., under controlled
conditions.

test method The technical procedures and
actions that are required to determine whether
or not a particular product conforms with a rele-
vant standard.

test pile A pile, 1 used to determine the load
that it can support without settling; this determi-
nation usually is made by placing heavy weights
on a platform mounted on the top of the pile.

test pit An excavation made to examine an
existing foundation, or to determine whether an
area is suitable for building construction;
includes the taking of soil samples and the deter-
mining of the depth of groundwater.

test plug In a drainage system, a plug which is
installed in the system being tested for leaks.
The test plug is connected to an air compressor
(through a valve) that is used to inflate it and
seal the drain.

*- Test plug

* JIM* SHiADU

test plug

test pressure In plumbing, the water pressure
or air pressure to which the pipes and fittings, 1
are subjected when they are tested for water-
tightness and strength.

test tee In plumbing, a special pipe tee which is
inserted in a drainage system; provided with a
mechanism for producing water test pressure to
check the system for leaks.

testudinate Having a ridge roof.

testudo In Roman architecture, an arched vault
or ceiling, esp. when surbased or flattened.

tetraprostyle Said of a classical temple having a
portico of four columns in front of the cella or naos.

tetraprostyle: temple on the llissus, Athens (449 B.C.)

tetrapylon A structure characterized by having

four gateways as an architectural feature.
tetrastoon A courtyard with porticoes or open

colonnades on each of its four sides.
tetrastyle Having four columns in the front or

end row; consisting of a row or rows of four

columns.
textile A material, woven or knitted, that is

made from fiber or yarn.

989

textile mill

textile mill A factory in which woven fabrics
are manufactured. Many early mills were located
near a source of water power for operating the
machinery; most were of timber construction
and in constant danger of being consumed by
fire. In 1832, a significant advance in fire safety
occurred with the construction of a mill in
Rhode Island that was especially designed to
resist fire (and to burn slowly if ignited) by using
thick floor planking, by minimizing the number
of timber beams, and by maximizing the cross-
sectional area of each beam. These design crite-
ria, widely applied, greatly improved fire safety
in the mills.

texture The tactile and visual quality of a sur-
face or substance other than its color.

texture brick A rustic brick.

textured paint See plastic paint.

texture-finished paint See plastic paint.

TG&B Abbr. for "tongued, grooved, and
beaded."

thalamus, thalamium In early Greek archi-
tecture, an inner room or chamber, esp. the
women's apartment.

thatch The covering of a roof, or the like, usu-
ally made of straw, reed, or similar materials fas-
tened together to shed water and sometimes to
provide thermal insulation; in tropical countries
palm leaves are widely used.

thatched hut See palma hut.

T»head l.In precast framing, a segment of
girder crossing the top of an interior column. 2.
The top of a shore formed with a braced hori-
zontal member which projects on two sides,
forming a T-shaped assembly. 3. In plumbing,
same as curb cock.

theater A building or outdoor structure provid-
ing a stage (and associated equipment) for the
presentation of dramatic performances and seat-
ing for spectators.

theater-in-the-round An arena theater; also

see arena, 2.
theater seating Same as auditorium seating.

theatrical gauze A stiff gauze, 1, usually of
cotton or linen; used on the stage of a theater for
curtains or scenery.

theodolite A precision instrument used in sur-
veying; consists of an alidade which is equipped

Shakespearian theater: Fortune Theater, London,
mid- 17th cent.

with a telescope, a leveling device, and an accu-
rately graduated horizontal circle; also may carry
an accurately graduated vertical circle.

theologeion, theologium A small upper
stage or balcony in the stage structure of the
ancient theater, on which persons representing
divinities sometimes appeared and spoke.

therm A quantity of heat equivalent to 100,000
Btu.

thermae See bath, 3.

thermal barrier See thermal break.

thermal bath See bath, 3.

thermal break, thermal barrier An ele-
ment of low heat conductivity placed in an
assembly to reduce or prevent the flow of heat
between highly conductive materials; used in
some metal window or curtain wall designs
intended for installation in cold climates.

thermal bridge Same as cold bridge.
thermal capacity See heat capacity.

thermal conductance The time rate of flow
of heat through a unit area of material from one
of the faces of the material to the other, for a
unit temperature difference between the two
faces, under steady-state conditions.

thermal conduction The process of heat
transfer through a material medium in which
kinetic energy is transmitted by particles of the
material from particle to particle without gross
displacement of the particles.

990

thermal stress

thermal conductivity The rate of transfer of
heat by conduction; the amount of heat per unit
of time per unit area that is conducted through a
slab of unit thickness of a material if the differ-
ence in temperature between opposite faces is
one degree of temperature; a property of the
material itself, usually represented by the letter k
and called k factor.

thermal conductor A material which readily
transmits heat by means of thermal conduction.

thermal cutout An overcurrent protective
device in an electric circuit; contains a heater
element and a renewable fusible member which
opens when the current is so great as to produce
sufficient heat to melt it; not designed to inter-
rupt short-circuit currents.

thermal diffusivity The thermal conductivity
divided by the product of the specific heat and
unit weight; an index of the ease with which a
material undergoes a change in temperature.

thermal emissivity The ratio of the rate of
radiant heat energy emitted by a body at a given
temperature to the rate of radiant heat energy
emitted by a blackbody, 1 at the same tempera-
ture, in the same surroundings.

thermal endurance A measure of the capa-
bility of glass to withstand thermal shock.

thermal expansion The change in length or
volume which a material or body undergoes on
being heated.

thermal finish Same as flamed finish.

thermal-fusion joint Same as heat-fusion
joint.

thermal insulating cement A prepared
composition, in dry form, comprising granular,
flaky, fibrous, or powdery materials; when mixed
with a suitable proportion of water, it develops a
plastic consistency, and if applied to a surface,
dries in place and forms a covering that provides
thermal insulation.

thermal insulation, heat insulation A
material providing high resistance to heat flow;
usually made of mineral wool, cork, asbestos,
foam glass, foamed plastic, diatomaceous earth,
etc.; fabricated in the form of batts, blankets,
blocks, boards, granular fill, and loose fill.

thermal insulation board A preformed rigid
or semirigid material in board or block form,
which provides resistance to heat flow.

thermal insulation for covering a pipe

thermal load A load on a structure which is
induced by changes in temperature.

thermal mass Any material or wall that can
absorb heat or cold and release it at a later time.
Also see roof pond, rock storage, and Trombe
wall.

thermal movement Changes in dimension of
concrete or masonry as a result of temperature
changes.

thermal protector For a motor or motor-com-
pressor, a protective device which protects the
motor against dangerous overheating, due either
to failure to start or to overload.

thermal radiation The transmission of heat
from a hot surface to a cooler one in the form
of invisible electromagnetic waves, which, on
being absorbed by the cooler surface, raise the
temperature of that surface without warming
the space between.

thermal resistance The reciprocal of thermal

conductance.
thermal resistivity An index of a material's

resistance to the transmission of heat; the recip-
rocal of thermal conductivity.
thermal shock The sudden stress produced in

a body or in a material as a result of a sudden

temperature change.
thermal storage The means by which solar

energy is collected for re-radiation at a later

time.
thermal storage roof In a passive solar

energy system, a roof that provides thermal

mass; also see roof pond.
thermal storage wall In a passive solar energy

system, a wall acting as a thermal mass; located

between the collector and the space to be heated;

see Trombe wall.

thermal stress, temperature stress Stress intro-
duced by uniform or nonuniform temperature

991

thermal stress cracking

change in a structure or material which is con-
strained against expansion or contraction.
thermal stress cracking The crazing of some
thermoplastics as a result of overexposure to
high temperature.

thermal transference The steady-state flow
of heat from a body, through applied thermal
insulation, to the external surroundings, i.e.,
the time rate of heat flow per unit area of the
body surface per unit temperature difference
between the body surface and the external sur-
roundings.

thermal transmittance, U-value The time
rate of heat flow per unit area under steady con-
ditions from the fluid on the warm side of a
barrier to the fluid on the cold side, per unit
temperature difference between the two fluids.

thermal unit A unit of heat energy, such as the
British thermal unit (Btu) in the English system,
or the calorie in the metric system.

thermal valve A valve whose action is con-
trolled by a thermally responsive element.

thermite welding A welding process in which
the joining of the parts is produced by heating
with superheated liquid metal and slag resulting
from the ignition of a mixture of ferric oxide and
finely-divided aluminum particles; pressure may
be applied.

thermal window See insulating glass.

THERMO On drawings, abbr. for thermostat.

thermocouple A device consisting of two
junctions of two dissimilar metals, in an electric
circuit; when the two junctions are at different
temperatures, a voltage is generated by the
device; used for measuring temperature.

thermoforming The forming of thermoplastics
as a result of the application of heat that softens
the material.

thermometer A device for measuring temper-
ature.

thermometer well A specially designed
enclosure which is connected into a piping sys-
tem and into which a thermometer may be
inserted to measure fluid temperature.

Thermopane™ A proprietary name for a heat-
insulating glass.

thermoplastic A material which becomes soft
and pliable when heated (without change in its

other properties) and hard and rigid when
cooled again.

thermoplastic insulating tape A tape com-
posed of a thermoplastic compound; used to pro-
vide insulation at joints in an electric conductor.

thermoplastic protective tape A tape
which is composed of a thermoplastic compound
that provides a protective covering for electrical
insulation.

thermosetting Descriptive of a material such
as synthetic resin which hardens when heated or
cured, and does not soften when reheated.

thermosetting resin A synthetic resin which
assumes a permanent set under heat; cannot be
remolded once the set has taken place.

thermosiphoning A method of cooling a
house in which hot air rises to the upper part of
the house where an attic fan blows it to the exte-
rior; cooler exterior air at a lower height is then
drawn into the house.

thermosiphon solar energy system A
solar energy system in which the heat transfer
fluid circulates by convection as the less dense,
warm fluid (air) rises and is displaced by the
denser, cooler fluid (air).

thermostat An instrument which responds to
changes in temperature, and directly or indi-
rectly controls temperature.

thermostatic expansion valve A control-
ling device for regulating the flow of volatile
refrigerant into a cooling unit, actuated by
changes in cooling unit pressure and superheat
of the refrigerant leaving the cooling unit.

thermostatic mixer Same as shower mixer.

thermostatic switch A type of switch
installed inside security cabinets, vaults, etc. If
the temperature within the cabinet or vault rises
significantly above its normal value, the thermo-
static switch closes, thereby activating an alarm.

thermostatic trap A steam trap utilizing a
thermally actuated device to expand and close
the discharge port when steam flows through it,
and to contract and allow steam condensate to
flow through when the temperature of the fluid
drops to a predetermined value; usually used for
small steam loads such as radiators.

therm window Same as Venetian window.

thesaurus In ancient Greece, a treasury house.

thickness gauge Same as feeler gauge.

992

thread

thickness molding Same as bed molding.

thick set Said of a ceramic tile that has been set
in a thick bed of mortar.

thief-resistant lock A mechanical device
that is especially effective in preventing unau-
thorized entry.

thimble 1. A protective sleeve of metal which
passes through the wall of a chimney to hold the
end of a stovepipe or smoke pipe. 2. The socket
or bearing attached to an escutcheon plate in
which the end of the knob shank rotates.

thimble, 1

T-hinge, tee hinge A surface-mounted door

hinge in the shape of the letter T, of which one

leaf, the strap, is fastened to the door, and the

other (short and wide) is fixed to the doorpost.
thinner, dilutent, solvent A volatile liquid

used to dilute and lower the viscosity of paints,

adhesives, etc.
thinning ratio The amount of thinner that is

recommended for a given quantity of paint.
thin»set Said of a ceramic tile that has been set

in a thin layer of mortar.
thin»set terrazzo Same as special matrix ter-

razzo.
thin-shell concrete Thin reinforced concrete

in the shape of a large shell, 1 or section thereof.
thin-shell precast Precast concrete which is

characterized by relatively thin slabs and web

sections.
thin stone Stone that is less than 2 in. (5 cm)

thick.
thin-wall conduit Electric conduit which has a

wall thickness insufficient for providing threads;

the ends are joined by couplings which slip over

the ends and which are held in place by setscrews.
thixotropic That property of certain gels of

becoming liquid when shaken or stirred.
THK On drawings, abbr. for "thick."

thole 1. Same as tholos. 2. A niche or recess in
which votive offerings were made. 3. A knot or
escutcheon at the apex of a timber vault.

tholobate The circular substructure of a dome.

tholos l.In Greek architecture, any round
building. 2. The corbeled, domed tombs of the
Mycenaean period. 3. A domed rotunda.

tholos, 1 at Epidaurus, plan

tholos tomb See beehive tomb.
tholus Same as tholos.

thread The prominent spiral part of a screw; a
ridge of uniform section in the form of a helix on

thread: terminology

993

threaded anchorage

the external or internal surface of a cylinder.

Also see taper thread.
threaded anchorage In posttensioning, a

device used for anchorage; has threads to attach

the jacking device more easily and to effect the

anchorage.
threaded joint A mechanical joint between

threaded pipes or between a threaded pipe and

threaded fitting.

m-msm

MLTX

threaded joint

thread escutcheon A small metal plate
placed around any small opening, as a keyhole.

three-bay threshing barn, three-bay barn

Same as Yankee barn.

three-centered arch An arch whose inner
curved surface is struck from three centers,
resulting in a shape approximating one -half an
ellipse. Compare with two-centered arch.

three-coat 'work In plastering, the application
of three successive coats: scratch coat, brown
coat, and finish coat.

three-decker A pulpit for a meetinghouse
with the clerk's desk at the bottom, the reader's
desk above it, and the pulpit on top.

three-ended barn See straw shed.

three-hinged arch An arch with hinges at the
two supports and at the crown.

three-hole basin A wash basin provided with
two openings, one each for the control of the
flow of hot and cold water, and a third opening
for a faucet.

three-light window l.A window with three
panes. 2. A window which is three panes high or
three panes wide.

three-part window l.A window having
three sashes of the same height and in the same
plane; there is a wide rectangular sash at its cen-
ter and a narrower sash on each side; essentially
the same as a Palladian window with the
rounded head of the center sash lopped off at the
top. 2. Same as treble sash.

three-pinned arch Same as three-hinged arch.

three-ply Consisting of three layers, thick-
nesses, laminations, etc., as veneers in plywood;
where the layers have a grain or orientation, usu-
ally the grain in adjacent layers is opposite.

three-pointed arch See equilateral arch.

three-point lock A device which locks the
active leaf of a pair of doors at three points;
sometimes required on doors having a 3-hr fire
rating.

three-quarter bat Same as three-quarter brick.

three-quarter brick A brick which is equal to
three-quarters of the length of a full-sized brick.

s 1

S |

f * / s

- J

•

s
i /

/
I •

three-quarter brick

three-quarter Cape house A Cape Cod
house that has two double-hung windows on
one side of the front door and only one on the
other side of the door.

three-quarter Cape house

three-quarter closer Same as king closer.

three-quarter closer

994

through stone

three-quarter header A header whose length is
equal to three-fourths of the thickness of the wall.

three-quarter house A Cape Cod house or
saltbox having two windows on one side of the
front door and one window on the other side.

three-quarter-turn Descriptive of a stair which,
in its progress from top to bottom, turns 270°.

three-quarter view A view of an object which
is midway between a front and a side view.

three-room plan A once-popular plan con-
sisting of a parlor, hall, and kitchen lined up
along the front of the house. The entry door,
which was not centered on the facade, usually
opened directly into the kitchen.

three-way strap A steel strap which is shaped
to fit and join three members of a wood truss;
fastened with bolts or screws.

three-way switch An electric switch, used in
conjunction with a similar switch, to control
lights from two different points, as from two dif-
ferent ends of a hallway.

three-wire system An electric wiring system
which utilizes three conductors; one of the wires
(the "neutral wire") is maintained at a potential
midway between the potentials of the other two.

threshing barn Same as Yankee barn.

threshing floor The section of a barn where
wheat is separated from the chaff and also where
hay is stored. In some early barns, the threshing
process took up an entire floor.

threshold l.A strip fastened to the floor
beneath a door, usually required to cover the
joint where two types of floor material meet;
may provide weather protection at exterior
doors. Also see doorsill. 2. In illumination engi-
neering, the value of physical stimulus which
permits an object to be seen a specified percent-
age of the time with specified accuracy.

throat 1 . A groove that is cut along the under-
side of a projecting member (for example, under
a belt course) to prevent rainwater from running
back across it toward the wall; also called a drip
molding. 2. Same as chimney throat.

throated sill The lowest horizontal member of
a window frame; a groove cut along the under-
side of the frame retards the flow of rainwater
back toward the wall.

throating l.A drip or drip mold. 2. See throat.
3. A chimney throat.

throat opening In a steel doorframe, the open-
ing between the backbends of the frame.

throttling valve In a piping system, an orifice
designed to control the rate of flow through it.

through-and-through-sawn Same as plain-
sawn.

through arch Any arch which is set in a thick,
heavy wall.

through bolt A bolt which passes completely
through the members it connects.

through bond In a masonry wall, the trans-
verse bond formed by stone units or bricks
extending through the wall.

through check In a timber, a check which
extends from one surface through to the oppo-
site side.

through dovetail See common dovetail.

through gutter A gutter having parallel sides.

through lintel A lintel whose thickness is that
of the wall in which it is placed.

through lot A lot, other than a corner lot,
having frontage on two public streets or high-
ways.

through penetration An opening that passes
through both sides of a fire-resistive construction.

through shake In timber, a shake which extends
between any two faces.

through stone A stone that is set with its
longest dimension perpendicular to the face of a
wall and whose length is equal to the thickness
of the wall.

through stones

(indicated by arrows)

995

through tenon

through tenon A tenon that extends com-
pletely through the piece into which its corre-
sponding mortise is cut.

through-the-cornice wall dormer See wall
dormer.

through-wall flashing A flashing which ex-
tends through a wall, from one side to the other.

through-wall flashing

throw 1 . The horizontal or vertical axial distance
an airstream travels after leaving an air outlet to
the point where the airstream velocity is reduced
to a specific value; also called blow. 2. The effec-
tive distance between a lighting fixture and the
area being lighted. 3. The maximum distance
that a bolt projects when it is fully extended.

THRU On drawings, abbr. for "through."

thrust 1 . The amount of push or force exerted
by or on a structure. 2. In an arch, the resultant
force normal to any cross section of the arch.

thrust bearing A support for a shaft designed
to take up its end thrust.

thrust line In an arched structure, the line of
action of the resultant compressive force.

thrust stage A stage in a theater that does not
have a proscenium; the stage is surrounded on
three sides by the audience.

thuja Same as thuya.

thumbat In roofing, a hook for fastening sheet
lead.

thumb knob Same as turn knob.

thumb latch A lift latch for securing a door in
a closed position, usually by means of a flat bar
that falls into a catch when pressed by the
thumb; for example, see Norfolk latch and Suf-
folk latch.

thumb molding A narrow convex molding
which is flattened in cross section.

In medieval pointed vaulting, a section taken

at the level of the head of the flying buttress;

arrows indicate the directions of thrust

thumbnail bead A quarter-round molding cut
into the edge of a board so that it is recessed
slightly from the surface.

thumb nut Same as wing nut.

thumb piece A small pivoted part above the
grip of a door handle; pressure on this part, by
the thumb, causes the latch bolt to operate.

thumb plane A very small, narrow carpenter's
plane.

thumbscrew A screw having a broad head
that is knurled or flattened so that it may be
turned easily by the thumb and one finger.

thumb turn Same as turn knob.

thurm To work moldings, or the like, across
the grain of the wood with a saw and chisel,
producing an effect similar to turning on a
lathe.

thuya, western red cedar, Pacific red
cedar A soft, lightweight, straight coarse-
grained wood that is relatively weak; the sap-
wood is white, the heartwood is reddish; because
of its durability it is widely used for shingles,
tanks, and other exterior applications.

thymele In the orchestra of an ancient Greek
theater, a small altar dedicated to Bacchus; usually

996

tier structure

at the center of the orchestra circle and marked by
a white stone.

thyroma 1. Of an ancient house, a door which
opens on the street. 2. A large doorway in the
second story at the rear of the stage of the
ancient Roman theater.

thyrorion, thyroreum Of an ancient Greek
house, a passageway leading from the entrance
to the peristyle.

tide mill A mill, such as a gristmill or sawmill,
operated by a waterwheel powered by tidal water
confined in a reservoir after high tide. An
incoming tide opens a gate, permitting tidal
water to fill the reservoir; when the direction of
the tide changes, the gate is closed by hand, and
then the outflowing tidal water turns the mill's
waterwheel.

Tidewater cottage A one-room cottage in the
Chesapeake Bay region of Virginia, after about
1630.

tie 1 . Any unit of material which connects two
parts, as masonry to masonry. Also see wall tie.
2. A framing member which sustains only a ten-
sile load; a member in tension to prevent spread-
ing. 3. In surveying, a connection from a point of
known position to a point whose position is
desired.

METAL TIE

AIR SPACE

metal ties, 1

masonry ties, 1

tieback A tension element used to resist the
lateral force on a retaining structure.

tie bar 1. A flat bar used as a tie or a tie rod. 2.
A deformed bar, embedded in a concrete con-
struction at a joint and designed to hold abut-
ting edges together; not designed for direct-load
transfer.

tie beam l.On individual pile caps or spread
footings which are eccentrically loaded, a beam
(usually of reinforced concrete) used to distrib-
ute horizontal forces to other pile caps or foot-
ings; a strap, 2. 2. In roof framing, a horizontal
timber connecting two opposite rafters at their
lower ends to prevent them from spreading; also
see collar beam.

tied arch An arch having a tie between the
skewbacks of the arch ends in order to provide a
horizontal reaction component.

tied column A column which is reinforced lat-
erally with ties.

tie iron Same as wall tie.

tien A basic Chinese structure used for domes-
tic, public, and religious buildings; consists of a
platform supporting a structural wooden frame-
work of at least four columns and longitudinal
and transverse tie beams, on which rest the roof
trusses of the prominent, upward-curving, high-
pitched, tiled roof. Enclosures and interior parti-
tions are nonbearing screen walls.

tie piece Same as tie beam, 2.

tie plate l.Any plate used to tie together
two components or parallel parts of a built-up
structural-steel member. 2. Same as batten plate.

tie point The point of closure of a survey, either
on itself or on another survey.

tier A row, or a group of rows placed one above
the other, as rows of seats in a theater or of
beams in construction.

tier building A multistoried building, the
floors of which may or may not be partitioned.

tierceron In medieval vaulting, a secondary rib
springing from an intersection of two other ribs;
an intermediate rib that rises between the main
diagonal and transverse ribs from the impost of
the pier to the ridge rib.

tie rod A rod in tension, used to bind parts of a
structure together. (See illustration p . 998.)

tie stone A stone serving as a tie, 1 .

tier structure A multistory framed building.

997

tie wall

tie rod

tie wall A wall built at right angles to a spandrel
wall to increase its lateral stability.

tie wire An annealed iron wire, used to tie steel
reinforcing bars together in reinforcement, 1.

Tiffany glass See opalescent glass and stained
glass.

tige The shaft of a column, from the base mold-
ings to the capital.

tigerwood A grayish to dark brown wood of
western Africa; of moderate density; highly fig-
ured and with high luster; used for interior car-
pentry and plywood.

tight building A building in which air infiltra-
tion is kept to a minimum to reduce heating and
cooling costs.

tight knot See sound knot.

tight sheathing l.Tongue-and-grooved boards
or dressed-and-matched boards nailed to rafters
or studs to serve as a base for an outer covering;
may be fastened either at right angles or diagonal
to the supports. 2. Same as closed sheeting except
that the vertical sheathing planks are interlocked;
used in saturated soils; sometimes steel sheet pil-
ing is used instead of wood planking.

tight sheeting Same as closed sheeting.

tight side The side of veneer which originally
faced outward in the log or flitch when the
veneer was cut from it.

tight tolerance A tolerance in a specification
that holds the permissible deviation from the
specification to a minimum value.

tile 1. A glazed or unglazed ceramic unit for fin-
ishing a surface; usually thin in relation to the
dimensions of its face. 2. A surfacing unit of slate
or of some other impervious composition; also

see brick-tile, chimney tile, clay tile, corner tile,
crown tile, Dutch tile, encaustic tile, fireplace
tile, hollow clay tile, mission tile, pantile, ridge
tile, rounded tile, Spanish tile, structural clay tile.

tile-and-a-half tile Tile having the same
length, but 1 Vi times the width, of the tile used
elsewhere on a roof.

tile arch A floor arch, 2 made of terra cotta.

tile batten See slate batten.

tileboard 1 . A wallboard used for interior fin-
ishing; usually a base sheet material overlaid
with a hard, glossy decorative facing to simulate
tile. 2. Square or rectangular boards, usually
made of compressed wood or vegetable fibers,
often with beveled interlocking edges, used for
ceiling or wall covering.

tile creasing A weather-protective barrier at
the top of a brick wall; consists of two courses of
tiles which project beyond both faces of the wall,
so as to throw off rainwater. Also see creasing.

tile drain See drain tile.

tile field A system of distribution tile.

tile fillet Tiles cut to form a fillet, and set in
mortar against a wall adjoining a roof surface in
lieu of flashing.

tile hammer A brick hammer of reduced size;
used to cut glazed brick and tile and, in some
cases, facing brick; not used for heavy-duty
work, which is performed with a brick hammer.

tile hanging Same as weather slating.

tile listing Tile used to create a splayed fillet at
an abutment.

tile pick A sharp pointed hammer used to pick
holes in tile units.

tile pin A pin passing through a roofing tile into
the wood beneath to hold the tile in place.

tile shell In a structural clay tile, the outer shell
of the hollow unit.

tile shingle See shingle.

tile strip Same as slate batten.

tile tie A heavy braided wire used to secure tile
to a roof.

tile valley On a roof, the valley between two slop-
ing plane surfaces formed with specially made tiles.

tiling plaster See Keene's cement.

till, glacial till, boulder clay An unstrati-
fied glacial deposit which consists of pockets of
clay, gravel, sand, silt, and boulders; has not

998

timber-framed house

been subject to the sorting action of water; usu-
ally has good load-sustaining properties.

tilting concrete mixer See tilting mixer.

tilting-drum mixer Same as tilting mixer.

tilting fillet, cant strip, doubling piece, tilt-
ing piece A thin wedge-shaped strip of wood
placed under the slates or tiles of a roof to tilt the
bottom course; used where needed to shed water
more effectively. Also see arris fillet.

tilting level A level, 1 in which the final level-
ing of the instrument is obtained by small con-
trolled amounts of rotation of the telescope
about a horizontal axis.

tilting mixer A horizontal-axis cement mixer
whose drum can be tilted; the materials are fed in
when the discharge opening of the drum is raised,
and the mixture is discharged by tilting the drum.

tilting piece See tilting fillet.

tilt-up construction Construction of con-
crete wall panels which are cast horizontally,
adjacent to their final positions, and then tilted
up into a vertical position when hardened.

timber 1. Uncut trees or logs that are suitable for
conversion to lumber. 2. Wood sawn into balks,
battens, boards, etc., suitable for use in carpentry,
joinery, and general construction. 3. Square-sawn
lumber having: (US) a minimum dimension of 5
in.; (Brit.) approximately equal cross dimensions
greater than 4 in. by 4Min. (101.6 mm by 114-3
mm). 4. A heavy wooden beam used as a shoring
or bracing system member.

timber bond In masonry, a chain bond formed
by the use of timber.

timber brick Same as wood brick.

timber building Same as timber-framed building.

timber connector One of a number of metal
connectors used (with bolts) to join timber in
heavy construction; usually the connector has a
series of sharp teeth which dig into the wood as
a bolt is tightened, thereby preventing lateral
movement and decreasing the number of bolts
required; another type employs a sharp round
ring to perform this function.

timber dog A dog iron suitable for joining two
timbers.

timber-framed building A building having
timbers as its structural elements (except for the
foundation); for a description of the major indi-
vidual components used in such a structure, see

spike grid timber connector; joint employing
two timber connectors is shown below

collar beam, girt, joist, plate, purlin, rafter, sum-
merbeam, windbrace.

timber-framed house A house in which the
major structural components were huge timber

end girt

timber-framed house with terminology
for many structural members

999

timber framing

posts and beams or girts. The space between
these structural timbers was usually filled with
brick, plaster, mud, wattle-and-daub, or the
like. The exterior of the building was often
coated with hard plaster and then sheathed
with weatherboarding, or covered with slates or
shingles as protection against the penetration
of rain and to provide improved thermal insula-
tion.

timber framing See frame.

timber house A type of house, usually lofty,
found in secular Gothic architecture, especially

timber house: Market Place in Hildeshe
Lower Saxony, Germany

in Central Europe; characterized by a lower story
of masonry which supports the timber construc-
tion above, usually with richly carved gables.

timbering Any temporary work in timber, as
formwork for concrete, shoring, etc.

timber joint connector Same as timber con-
nector.

timber stresses In stress-graded lumber, the
stresses which conform to recognized values.

time Time limits or periods stated in the con-
tract. A provision in a construction contract
that "time is of the essence of the contract" sig-
nifies that the parties consider that punctual
performance within the time limits or periods in
the contract is a vital part of the performance
and that failure to perform on time is a breach
for which the injured party is entitled to dam-
ages in the amount of loss sustained, or is
excused from any obligation of further perfor-
mance, or both.

time and materials (T&M) The time and
total cost of all materials required to complete a
construction job; often used where the cost of
the job is otherwise difficult to estimate.

time-delay fuse Any fuse in an electric circuit
that takes more than 12 seconds to open at a
200% load.

timely completion Completion of the work, 1
or designated portion thereof on or before the
date required.

time of completion The date established in
the contract, by name or by number of days, for
substantial completion of the work. Also see
completion date and contract time.

time of concentration In a storm-water
drainage system, the time required for storm
water to travel from the most remote portion of
the tributary area to an inlet or drain.

time of haul In production of ready-mixed
concrete, the period from first contact between
mixing water and cement to the discharge from
the mixer of the freshly mixed concrete.

time of set See initial setting time, final setting
time.

time system A system of clocks and control
devices, with or without a master timepiece,
which will indicate time at various remote loca-
tions; the master timepiece may have additional
facilities to program other systems, such as bells.

1000

tobacco barn

tin 1. A lustrous white, soft, and malleable metal
having a low melting point; relatively unaffected
by exposure to air; used for making alloys and
solder and in coating sheet metal. 2. To coat
with a layer of tin.

tin-canning See oil-canning.

tin cap A small flat metal washer used under
roofing nails.

tin ceiling See metal ceiling and pressed-metal
ceiling.

tin-clad fire door A door of two- or three-ply
wood-core construction, which is covered with
No. 30 gauge galvanized steel or terneplate
or No. 24 gauge galvanized steel sheets.

tinfoil A very thin sheet of tin, now replaced by
other foils such as aluminum.

t'ing A four-sided, open, wooden pavilion of
Chinese origin; consists of uprights supporting
an upward-curving roof by means of tie beams
and brackets.

tingle 1 . A support which reduces the sag in a
long line used in laying brick. 2. A flexible metal
clip used to hold a sheet of glass, metal, etc.

tinning, precoating Coating a metal with sol-
der or tin alloy, prior to soldering or brazing it.

tinplate Thin iron or steel sheets which have
been plated with tin as a protection against oxi-
dation.

tin roofing A roof covering of flexible tin-plate
or terneplate metal.

tin saw A saw used for cutting kerfs in bricks.

tin snips Shears with a blunt nose; used for cut-
ting thin sheet metal.

tint A light color made by mixing a small amount
of the pure color with a large amount of white.

tinted glass Glass which has been tinted, usually
to filter out near-infrared solar energy, thereby
reducing the solar heat gain through the glass and
reducing the load on the air-conditioning system.

tinter See stainer.

tinting strength, staining power The abil-
ity of a pigment to modify the color of a standard
white or colored paint.

tipi A relatively lightweight, transportable, con-
ically shaped dwelling primarily of American
Indians of the Great Plains; its base was gener-
ally egglike in plan, with the narrower end of the
base at the entrance. The framework consisted

of heavy wood poles, fixed in the ground at their
lower ends and lashed together at the top. This
framework was covered with decorated water-
proof animal skins, sewn together with sinew
and secured to the ground by pegs driven
through loops at the base of the cover. Another
type of tipi, used by tribes in the eastern regions
of America, had a domed rather than a conical
framework consisting of branches bent over, tied
together, and covered by bark or animal skins
sewn together with sinew to provide a water-
proof covering. Also spelled tepee or teepee.

tirant 1. A tie beam. 2. A tie rod.

T-iron See tee iron.

titanium dioxide A white pigment having a
very high opacity; used in paints; occurs in two
crystalline forms, anatase and rutile, of which
the latter has higher opacity.

titanium 'white A pigment consisting primar-
ily of titanium dioxide; bright white in color; has
high hiding power and good permanence.

tithe barn A barn once used by farmers to hold
their contributions to the church in the amount
of one-tenth of their harvested crops.

title A legal right to the ownership of property.
Also see abstract of tide.

title insurance Insurance, offered by a com-
pany, that the title to property is clear or that it
may be cleared by curing specified defects.

title search An inquiry into the historical own-
ership record of a property in order to ascertain
its true ownership and the possible existence of
any liens or easements on the property which
might affect its sale.

tjandi A Hindu sepulchral monument, preva-
lent in Java from the 8th to 14th cent. A.D., con-
sisting of a square base, a cella-like temple, and a
prominent pyramidal roof structure; a small
room in the base contained the urn with the
ashes of the prince in whose memory the struc-
ture was erected.

T-joint See tee joint.

TL Abbr. for transmission loss.

TMA Abbr. for "Tile Manufacturers Association."

tobacco barn A barn used for curing tobacco
leaves, with or without the addition of heat, by
hanging them from a series of horizontal poles
within the barn; occasionally called a tobacco
house. Three common types of tobacco barns are

1001

toe

designated by the curing process employed: air-
cured, fire-cured, and flue-cured.

toe 1 . A projection from the foot or foot piece of
any object or construction to give it broader
bearing and greater stability. 2. That part of the
base of a concrete retaining wall which projects
in front of the face of the wall, away from the
retained material. 3. That portion of sheeting
below the excavation subgrade. 4. On a door,
the lower portion of the lock stile. 5. Of a weld,
the junction between the base metal and the
face of a weld. 6. To drive a nail at an oblique
angle.

toeboard 1. A board placed around a platform
or on a sloping roof to prevent workmen or
materials from falling. 2. A member that forms
the lowest vertical face of a kitchen cabinet, or
the like, at toe level.

toe crack A crack, at the toe of a weld, in the
base metal.

toed In carpentry, said of a board, strut, etc.,
having the end secured by nails driven obliquely.

toehold A batten or board which is nailed, tem-
porarily, to a sloping roof to act as a footing for
workmen.

toe in The small reduction in the outside diam-
eter of a plastic pipe at its cut end.

toe joint A joint formed between a horizontal
timber and another at some vertical angle with
it, as between a rafter and a wall plate.

toenailing, skew nailing, tusk nailing
Nailing obliquely to the surfaces being joined;
alternate nails may be driven at opposite angles
to provide increased holding power.

toenailing wood-strip flooring

toe piece Same as ledger, 2.

toeplate 1. Same as kickplate, 2. 2. A flat metal
bar attached to the outer edge of a metal grating
or to the rear edge of a tread, and projecting

above the top surface of the grating or tread so as
to form a lip or curb.

toe wall At the bottom of an embankment, a
low wall built to prevent the earth from slipping
or spreading.

toggle bolt A bolt having a nut with pivoted,
flanged wings that close against a spring when it is
pushed through a hole, and open after emerging
from the hole; used to fasten objects to a hollow wall
or to a wall which is accessible only from one side.

wood

block

toggle
bolt

toggle bolts

toggle switch A lever-actuated snap switch.

flush-mounted toggle switch

toilet 1. A water closet; W.C. 2. The room con-
taining the water closet.

toilet enclosure In a toilet room having a
number of water closets, one of the compart-
ments which provides individual privacy.

1002

tooled finish

toilet partition One of the panels forming a
toilet enclosure.

toilet room An enclosed space containing one
or more water closets, lavatories, toilet enclo-
sures, urinals, and other plumbing fixtures; also
see bathroom.

tokonoma In the Japanese house, an alcove,
raised above the floor, for displaying a hanging
scroll and a flower arrangement.

TOL On drawings, abbr. for tolerance.

tolerance The permissible deviation in a speci-
fied size or dimension.

tollhouse 1. A house near a tollgate of a high-
way or bridge, serving as the residence of the
keeper. 2. A tollbooth.

Toltec architecture An austere geometric
Mesoamerican architecture, ca. 1000 A.D., which
formed the basis for Aztec architecture and other
architecture of Mesoamerica.

torn Same as shore.

tomb In architecture, a memorial structure over
or beside a grave.

tomb chest A stone coffin-like box.

ton l.The equivalent of 2,000 lb (907.2 kg).
Also see metric ton. 2. A unit of refrigeration
capacity equal to 200 Btu per minute, the equiv-
alent cooling provided by the melting of one ton
of ice in one hour.

tondino 1 . A small tondo. 2 . A circular molding.

tondo A circular plaque or medallion.

toner An undiluted organic pigment; contains
little or no inert matter.

tongue A projecting member, either as a contin-
uous ridge along the edge of a board or plank, or
as a tenon on the end of a wood member;
intended to be fitted into a corresponding groove
or opening in another member to form a joint.

tongue-and-dart molding A decorative
molding consisting of a tonguelike ornament
alternating with a dartlike ornament.

and egg-shaped ornaments. Compare with egg

and dart,
tongue-and-groove boards See dressed-

and-matched boards.
tongue-and-groove joint, T and G joint A

joint formed by the insertion of the tongue of one

member into the corresponding groove of another.

tongue-and-dart molding

tongue and egg molding A decorative
molding consisting of alternating tongue-like

TONGUE

tongue-and-groove joint

tongue-and-groove material See dressed-
and-matched-boards.

tongue-and-lip joint A type of tongue-and-
groove joint in which the joint is concealed by a
flush bead on the board with the tongue.

tongued miter A miter joint which incorpo-
rates a tongue.

tongue joint A split joint formed by inserting a
tongue or wedge-shaped piece into a corre-
spondingly grooved piece in another member; if
metal, such a joint may be welded.

tonk strip A steel adjustable support for a shelf.

tonne A metric ton; a unit of mass equal to
1000 kilograms (approximately 2205 pounds).

ton of refrigeration A refrigerating effect
equal to 12,000 Btu (3,024 cal) per hour.

ton slate Random-sized slate which is pur-
chased by weight.

tooled ashlar Stonework having a tooled
finish.

tooled border A tooled, ashlar surface having
a decorative border consisting of double alter-
nating squares.

tooled finish, tooled surface In stonework,
a fluted, flat surface that usually carries 2 to 12
concave grooves per inch (5 to 30 per centime-
ter); also called tooling.

1003

tooled joint

tooled joint Any masonry joint that has been
prepared with a tool before the mortar in the
joint has set rigidly.

tooled joint

tooled surface A tooled finish.
tooled work See batted work.

tooling 1. Compressing and shaping the face of
a mortar joint. 2. See tooled finish. 3. See batted
work. 4. Compacting and contouring a sealant
in a joint.

tooling time After the application of a sealant
in a joint, the time interval during which tool-
ing, 3 is possible.

tool pad A tool, consisting of handle and clamp
or chuck, for holding small tool bits, such as
awls, screwdriver blades, etc.

tooth 1. In a paint film, a fine texture imparted
either by pigments or by the abrasives used in
sanding; this texture provides a good base for
the adhesion of a subsequent coat of paint. 2. A
dogtooth, 2.

tooth chiseling Cutting parallel stripes on the
surface of a stone slab with a stonecutter's chisel.

toothed plate, bulldog plate A toothed
metal plate that serves as a timber connector.

toothed plate

toothed ring A metal ring with toothed edges

which serves as a timber connector.
toother Same as dogtooth, 2.

toothing Cutting out alternate courses in old
work to provide a bond for new work.

toothing plane A carpenter's plane, the cut-
ting edge of which is formed into a series of small
teeth, usually to roughen a surface.

tooth ornament, dogtooth A decoration,
generally in the hollow of a Gothic molding,
consisting of four-leaved flowers, the centers of
which project in a point.

tooth ornament

top-and-bottom cap One of the horizontal
metal channels, attached at the jobsite to the top
and to the bottom of a hollow-metal door which
does not have an integral flush top or bottom.

top beam A collar beam.

top car clearance The shortest vertical dis-
tance between the top of an elevator car (or
crosshead, if provided on the car) and the near-
est overhead obstruction when the car floor is
level with the top terminal landing.

topcoat The final coat of paint applied to a sur-
face; usually applied over a primer and/or one or
more undercoats or surfacers.

top-course tile The uppermost course of tile,
laid along the ridge of a roof; usually shorter
than the others.

top cut The vertical cut at the upper end of a
rafter.

top dressing A layer, usually thin, of manure,
humus, loam, etc., to improve soil conditions in
planted areas.

tope See stupa.

top form A concrete form required on the upper
or outer surfaces of a sloping slab, a thin shell, etc.

top-hinged in-swinging window A win-
dow having a sash (ventilator, 2) which is
hinged at the top and swings in at the bottom.

top-hung window A casement window hung
by a hinge running along its upper edge.

topiary work The clipping or trimming of
plants, trees, and shrubs, usually evergreens, into
ornamental and fantastic shapes.

top lap In shingle roofing, the shortest distance
between (a) the lower edge of an overlapping

1004

torana

shingle and (b) the upper edge of the lapped unit
in the course directly below.

toplighting Lighting from above.

top mop See pour coat.

topographic survey The configuration of a
surface including its relief and the locations of
its natural and man-made features, usually
recorded on a drawing showing surface varia-
tions by means of contour lines indicating
height above or below a fixed datum.

top out To complete the uppermost course or

the highest structural member in a construction.

topping 1 . A layer of high-quality concrete or
mortar placed to form a floor surface on a con-
crete base. 2. The mixture of marble chips and
matrix which, when properly processed, pro-
duces a terrazzo surface.

topping coat A floated coat.

topping compound Same as finishing com-
pound.

topping joint In a topping, 1, a joint which is
directly over an expansion joint in the concrete
base.

topping out The placing of a flag or banner
(sometimes a tree — especially at Christmas
time) at the highest point of the framework of a
building when it is completed.

top plate l.The top horizontal member of a
frame building to which the rafters are fastened.

TOP

PLATES

1st FLOOR
STUD

top plate, 2

2 nd FLOOR
JOISTS

2. The horizontal member at the top of the par-
tition studs.
top rail l.The top horizontal structural mem-
ber of any piece of framing, as a door or sash.
2. A rail which is the top member of a railing
system.

top rail of a door

.TOP RAIL

top rail of a sash

topsoil l.The surface of upper layer of soil, as
distinct from the subsoil; usually contains
organic matter. 2. See loam.

torana, toran A monumental and richly deco-
rated gateway in the enclosure of a Buddhist
stupa in Indian architecture.

1005

torch brazing

torch brazing A brazing process in which the
required heat is furnished by a gas flame.

torchere l.An indirect floor lamp which sends
all or nearly all of its light upward. 2. An ornamen-
tal support for a flambeau or other source of light.

torching The application of a lime mortar
under the top edges of roof tiles or slates; in full
torching the mortar is applied beneath the
entire underside of slates between battens.

torch soldering A soldering process in which
the required heat is furnished by a gas flame.

tore Same as torus.

torii A monumental, freestanding gateway to a
Shinto shrine, consisting of two pillars with a
straight crosspiece at the top and lintel above it,
usually curving upward.

torii at Nikko, Japan

tormentor In a theater, one of a pair of curtains
or a rigid framed structure running parallel to
the front of the stage, just behind the prosce-
nium; used to frame the sides of the inner
proscenium opening and to conceal the offstage
wings from the audience.

torn grain A fuzzy or whiskered appearance in
the face of a wood shake, usually caused by cut-
ting the shake with a dull saw.

torque That which tends to produce rotation;
the product of a force and a lever arm which
tends to twist a body, as the action of a wrench
turning a nut on a bolt.

torque viscometer An apparatus for measur-
ing the viscosity of slurries.

torque wrench A wrench that incorporates a
gauge, such as a dial, that provides a numerical
indication of the torque that has been applied to
a shaft.

torreon A defensive tower used for protection
against enemy attack; a fortification once found
in some Spanish Colonial communities.

torsade, cable molding, rope molding 1.

A twisted or spiral molding. 2. Any ornamental
twist.

torsel A piece of timber, steel, or stone which
supports one end of a beam or joist and distrib-
utes its load.

torsion The twisting of a structural member
about its longitudinal axis by two equal and
opposite torques, one at one end and the other
at the opposite end.

torsional strength The resistance of a mate-
rial to being twisted about an axis.

torsional stress The shear stress on a trans-
verse cross section which results from the action
of a twist.

torso A spiral column, in Medieval and Renais-
sance architecture.

torus A bold projecting molding, convex in
shape, generally forming the lowest member of a
base over the plinth.

Torus

f-Cirjckire

Phnfh

torus molding

torus roll In sheet-metal or lead roofing, a
joint made at the intersection of two planes
having different slopes; allows for differential
movement.

toshnailing Nailing at an angle so the nail-
heads are not visible.

TOT. On drawings, abbr. for "total."

1006

trabeated

total float In CPM terminology, the difference
between the amount of time available to accom-
plish an activity and the time required.

total load See service load.

tot lot An outdoor playground for very young
children.

touch catch A door catch which releases auto-
matically if the closed door is pushed.

touch dry A stage during the drying of a paint
film when it can be touched lightly without the
paint's adhering and lifting when the finger is
removed.

toughened glass British term for tempered
glass.

toughness l.The ability of a structural mate-
rial to resist shock or impact; its ability to absorb
energy before fracture. 2. The ability of a
cladding, coating, or paint film to resist abra-
sion, chipping, or cracking.

tough-rubber sheath (Brit.) An abrasion-
resistant, corrosion-resistant, waterproof, pro-
tective covering for an insulated electric cable.

tourelle A turret.

tourist cabin One of a number of small sepa-
rate units, each providing overnight accommo-
dation for travelers; usually consisting of a
bedroom and bathroom, grouped in what was
once called a tourist court; found along well-
traveled highways during the first half of the
20th century; now replaced by motels.

tourist house A house used by travelers as a
lodging, often available with or without meals;
the total number of individuals that can be
accommodated is usually specified by the applic-
able local code.

towed grader See grader.

tower A structure or building characterized by
its relatively great height as compared with its
horizontal dimensions; also see shot tower and
torreon.

tower bolt Same as barrel bolt.

tower crane A type of crane consisting of a
fixed vertical mast which is topped by a rotating
boom, equipped with a winch for hoisting and
lowering loads and placing them at any location
within the diameter of the boom.

tower hoist In concrete handling in tall build-
ing construction, usually a tower, elevator

tower crane

bucket, and a movable receiving hopper set at
the level where the concrete is placed; the
bucket may be hoisted within the well of the
tower frame or external to it.

tower house 1 . A small castle consisting primar-
ily or entirely of a single tower. 2. Same as keep.

tower keep See keep.

town hall A public hall or building, belonging
to a town, where public offices are established,
the town council meets, the people assemble in
town meetings, etc.

town house l.A comfortable-to- luxurious
dwelling in an urban environment. 2. One of a
series of houses constructed in an unbroken row,
separated by party walls, often with a relatively
flat roof. 3. An upscale row house.

town plan A large-scale, comprehensive map
of a town or city that delineates its streets,
important buildings, and other urban features in
a detail compatible with the scale of the map;
also see city plan.

town planning See city planning and commu-
nity planning.

townscape 1 . A view of a town or city from a
single vantage point. 2. The planning and con-
struction of buildings within a town or city with
the objective of achieving overall aesthetically
pleasing relationships.

T»plan The basic floor plan of a building having
the shape of a capital letter T.

T»plate A flat metal plate in the shape of a T;
used to join two timbers, one of which butts
against the other, or to strengthen a joint.

trabeated 1. Descriptive of construction using
beams or lintels, following the principle of post

1007

trabeated system

and lintel construction, as distinguished from
construction using arches and vaults. 2. Fur-
nished with an entablature.

trabeated system A system of building con-
struction using beams or lintels to support the
weight over an opening.

trabeation Construction using beams and posts;
lintel construction.

trabes, trabs In ancient Rome, a beam, esp. a
long beam supporting the joists of a ceiling.

tracery The curvilinear openwork shapes of
stone or wood creating a pattern within the upper
part of a Gothic window, or an opening of similar
character, in the form of mullions which are usu-
ally so treated as to be ornamental. By extension,
similar patterns applied to walls or panels. See bar
tracery, branch tracery, fan tracery, etc.

car through friction between the sheave and the
wire ropes (cables) that hoist the car.
tractor A powerful engine-driven vehicle, on
wheels or on tracks, used for pushing or pulling
attachments or tools.

crawler tractor

tracery

trachelium In classical architecture, any mem-
ber (usually part of the necking) which comes
between the hypotrachelium and the capital.

tracing cloth A smooth linen fabric, coated
with size to make it transparent and suitable for
tracing.

tracing paper A transparent paper used for

tracing and original drawings.
track A U-shaped member, attached to the

floor and/or ceiling; used to receive metal studs

for a partition, or to guide a sliding partition,

door, curtain, etc.
track lighting Lighting provided by fixtures on

a lighting track.
traction load A load on a structure exerted by

a moving vehicle in the direction of its motion,

caused by friction, tractive effort, or braking.
traction machine On elevators, a machine

having a sheave which produces motion of the

tractor loader, tractor shovel A tractor
which has a bucket for digging, elevating, and
dumping its load at truck height.

trade 1. A person's occupation or craft, usually
involving manual skill. 2. In building construc-
tion, the classifications of work, such as
masonry, carpentry, plastering, etc.

trade granite See gneiss.

trading post A store, usually found in sparsely
settled areas, where inhabitants can exchange
products they make, grow, or trap, for goods sold
by the store.

trafficable roof A flat, asphalt-prepared roof
that provides protection against heavy foot traffic.

traffic board A board that protects a roof
surface from damage caused by people walking
on it.

traffic deck surfacing See topping.

traffic paint Paint specially formulated to with-
stand wear of vehicular traffic and to be highly
visible at night; used to mark center lines on
roadways, traffic lanes, crosswalks, etc.

traffic topping See topping.

trammel 1. In a fireplace, an adjustable hook for
suspending a cooking pot from a pivoted wrought-
iron horizontal bar attached to one of the fireplace
walls. 2. An instrument for drawing ellipses.

trammel point One of the two metal points on
a beam compass.

TRANS On drawings, abbr. for transformer.

1008

transit

transducer A device which converts power in
one kind of system to power in another form,
e.g., a loudspeaker which converts electric
power to acoustic power.

transenna Latticework of marble or metal
enclosing a shrine.

^■ : -*1^3&S33ess2&f£-:- ■

transenna: church at entrance of the Catacomhs
of St. Alexander, Rome

transept The transverse portion of a church
crossing the main axis at a right angle and pro-
ducing a cruciform plan.

transept aisle An aisle on the side of a transept.

transept chapel A chapel entered from a
transept, usually on its east side.

transfer In pre tensioning, the act of conveying
the stress in the prestressing tendons from the
jacks (or pretensioning bed) to the concrete
member.

transfer beam A beam that distributes the
load from the structure above it to that part of
the structure directly below it.

transfer bond In pretensioning, the bond stress
resulting from the transfer of stress from a pre-
stressing tendon to the concrete.

transfer column A column in a multistory
framed building that is not continuous down to
the foundation, but is supported at some inter-
mediate level where the load is transferred to
adjacent columns.

transfer girder A girder supporting a transfer
column.

transfer grille In an air-conditioning system, a
grille which permits air to flow from one space to
another; may be one of a pair, installed on oppo-
site sides of a wall, door, etc.

transfer length Same as transmission length.

transfer molding An injection molding using
a thermosetting material.

transfer register A transfer grille having a
mechanism for controlling the quantity of airflow.

transfer strength In pretensioning, the strength
the concrete must attain before stress is transferred
from the stressing mechanism to the concrete.

transfer switch A device arranged to switch an
electrical conductor from one circuit to another
without interrupting the flow of current.

transformer A device with two or more cou-
pled windings, used to convert a supply of elec-
tric power at one voltage to another voltage.

transformer bank Two or more transformers
located in the same enclosure, as in a trans-
former vault.

transformer box See instrument transformer
box.

transformer room An unattended room used
to house electric transformers and their auxiliary
equipment.

transformer vault An unattended isolated
enclosure having fire-resistant walls, ceiling, and
floor, for transformers and their auxiliary equip-
ment; often located below ground.

transillumination The illumination of a
material from the rear by light which is trans-
mitted through the material.

transit A surveying instrument used for the
measurement and laying out of horizontal and
vertical angles, distances, directions, and dif-
ferences in elevation; a type of theodolite hav-
ing an alidade with a telescope which can be
reversed in direction.

transit: a, tripod stand; b, leveling plates; /, vernier;
g, compass; h, W , levels; i, vertical circle; k, telescope

1009

transit-and-stadia survey

transit-and-stadia survey A survey in which
horizontal and vertical directions or angles are
observed with a transit and distances are mea-
sured by transit and stadia rod.

transitional style An architectural mode in a

period between two different architectural styles,

as for example, between late Georgian and early
Federal style; such a transition may occur at dif-
ferent times in different parts of a country.

transitional style: capital,
Church of St. Sehaldus, Nuremberg

transit line In surveying, any line of a survey
traverse which is projected, either with or with-
out measurement, by the use of a transit or the
like.

transit mix, transit-mixed concrete,
truck-mixed concrete Concrete that has
been mixed in a revolving-drum truck mixer.

transit-mix truck Same as truck mixer.

translation A linear displacement; in kinemat-
ics, a motion of a body such that a set of rect-
angular axes, fixed in the body, remains parallel
to a set of axes fixed in space.

translucent Descriptive of a material that
transmits light but diffuses it sufficiently so that
an image cannot be seen through the material
clearly.

translucent coating A liquid formulation
(such as varnish, shellac, or lacquer) which
when dry forms a translucent film.

translucent concrete A combination of glass
and concrete in precast or prestressed panels.

transmission coefficient See thermal trans-
mittance.

transmission factor See transmittance.

transmission length At the end of a preten-
sioned tendon, the distance necessary for the
bond stress to develop the maximum tendon
stress.

transmission loss Of a partition, the number
of decibels by which sound (incident on the
partition) is reduced in transmission through it;
a measure of the sound insulation value of the
partition — the higher the number, the greater
the insulation value.

transmissivity The capacity of a material to
transmit radiant energy.

transmittance When radiant flux is incident
on a medium, the ratio of the flux which
emerges from the medium to the flux which is
incident upon it.

transom 1 . A horizontal member, usually of
wood or stone, that separates a door from
a window, fanlight, or panel above it; some-
times called a transom bar. 2. An operable
window hinged to the transom, 1 directly
above a door. 3. A crossbar in a window frame
that divides a window horizontally. Also see
operable transom.

transom bar l.An intermediate horizontal
member of a doorframe, window frame, or simi-
lar structure. 2. A horizontal member which sep-
arates a door from a window, panel, or louver
above.

transom bracket A bracket supporting
an all-glass transom over an all-glass door when
the door has no metal top rail or transom bar, 2.

transom catch A fastener applied to a tran-
som and having a ring by which the latch bolt
may be retracted by means of a hook on a long
pole.

transom chain A short chain used to limit the
opening of a transom; usually provided with a
plate for attachment at each end.

transom frame A doorframe with a transom
bar, 2 and glass, a panel, or a louver above the
door opening.

transom lift A vertically operated device
attached to a doorframe and an operable tran-
som window, 1 , by which the transom may be
opened or closed.

transom light A glazed light above the tran-
som bar, 2 of a door.

1010

transverse rib

transom lift

^m—m

i—\

i i
i

.■.,[

transom lights

transom window 1. A transom light; may be

operable. 2. Any window operated by a transom

lift. 3. Any window divided by a transom bar.
transparent coating A liquid formulation

(such as varnish, shellac, or lacquer) which

when dry forms a transparent film.
transtrum In ancient Roman construction, a

horizontal beam.
transverse See chambranle.

transverse arch The arched construction
built across a hall, the nave of a church, or the
like, either as part of the vaulting or to support
or stiffen the roof.

transverse arch

transverse load A load, 1 applied perpendicu-
larly to the plane of the longitudinal axis of a
structure, such as a wind load.

transverse prestress In a member, prestress
that is applied perpendicular to the principal axis.

transverse reinforcement Reinforcement at
right angles to the principal axis of a member.

transverse rib A rib in vaulting spanning the
nave, aisle, or transept at right angles to its lon-
gitudinal axis and dividing its length into bays or
compartments.

transverse rib

1011

transverse seam

transverse seam See cross welt.
transverse section Same as cross section.
transverse shear A shearing action parallel to

the transverse axis of a body.
transverse strength l.The breaking load

applied normal to the neutral axis of a beam. 2.

Same as modulus of rupture.
transyte See tresaunce.
trap 1 . A device to maintain a water seal against

sewer gases, air, and odors; also called a stench

trap. 2. A removable section of a theater stage

floor. 3. Same as traprock.
trapdoor A door set into a floor, ceiling, or roof.
trapdoor monitor A section of a sloping roof

which is elevated so that it is at a flatter angle

than the remainder of the roof; has the appear-
ance of a trapdoor hinged along the upper edge;

does not run the full length of the roof.
trap elevator In a theater, an elevator below

the stage floor that lifts a trap, 2.
trapeze hanger A horizontal rigid member,

suspended by rods, on which pipes are supported

and/or clamped.
traprock A dark-colored igneous rock having a

fine-grained, more or less columnar structure.
trap seal In plumbing, the vertical distance

between the crown weir and the top of the dip of

the trap.
trap vent Same as back vent.

trascoro In Spanish church architecture, a part
of the choir separated from the main choir by an
open passage at the crossing.

trash A mixture of highly combustible waste such
as paper, cardboard cartons, wood boxes, and
combustible floor sweepings; contains up to 10%
by weight of plastic bags, coated paper, laminated
paper, treated corrugated cardboard, oil rags, and
plastic or rubber scraps; contains approx. 10%
moisture, and approx. 5% incombustible solids.
Also see garbage, refuse, and rubbish.

trash chute 1 . Any vertical smooth shaft used
to conduct rubbish, trash, or garbage from the
upper floors of a building to a trash storage bin or
room at the bottom end of the chute. 2. A tem-
porary shaft erected during the construction of a
multistoried building for the removal of debris.
3. See refuse chute.

trass A natural pozzolan of volcanic origin.

Gas supply pipe

Hanger rod

Roller

Bolt roller
to angle

Lock nut

trapeze hanger with roller support

trapeze hanger

INLET

OUTLET

CROWN WEIR
TRAP SEAL

trap seal

trass mortar A mortar made of a mixture of lime
and trass, with or without the addition of sand;
the trass provides protection against moisture.

T»rated switch A switch whose rating satisfies
the requirements of the National Electrical
Code for a tungsten-filament lamp load.

1012

tredyl

travated Divided into traves.

trave 1 . A crossbeam; a beam or a timber cross-
ing a building. 2. One of the divisions or bays, as
in a ceiling, made by crossbeams.

travel, rise Of an elevator, escalator, etc., the
vertical distance between the bottom terminal
landing and the top terminal landing.

travel distance At a specified point in a build-
ing, the distance between that point and a place
of safety, in the event of fire.

traveler, traveler curtain On the stage of a
theater, a curtain that closes the proscenium
when drawn.

traveling cable A cable, made up of electric
conductors, which provides an electric connec-
tion between an elevator or dumbwaiter car and
a fixed electrical outlet in the hoistway.

traveling crane A tower crane which is
mounted on crawlers, rubber tires, or rails.

traveling form Same as slipform.

traverse l.A screen, railing, or other barrier
across an opening to allow passage from one
place to another by an official or dignitary, but
to discourage unauthorized entry. 2. Same as
survey traverse.

travertine A variety of limestone deposited by
springs; usually banded; commonly coarsely cel-
lular; used as building stone, esp. for interior fac-
ing and flooring; some varieties are sold as
marble in the building trade.

traviated Having a series of transverse divisions
or bays, as in a ceiling.

travis See trave, 2.

tray ceiling Under a gabled roof, a horizontal
ceiling constructed part of the way up toward
the ridge.

trayle See vinette.

tray rail See food tray rail.

treacle molding A rounded molding or nosing
that is deeply undercut, upward to a groove that
acts as a drip to discharge rainwater.

tread The horizontal surface of a step; often has
a rounded edge that extends beyond the upright
face of the riser below it.

treading barn A circular two-story barn once
specifically constructed for threshing grain.
Horses or oxen were led around the second story
of the barn, across layers of wheat; the grinding

action of their hooves separates the wheat from
the chaff; the grain fell through gaps between the
floorboards into the granary in the story below.

tread length The dimension of a tread mea-
sured perpendicular to the normal line of travel
on a stair.

tread plate A floor plate which is fabricated of
metal, e.g., aluminum.

tread return In an open stair, the continuation
of the horizontal rounded edge of the tread,
beyond the stair stringer.

tread return

tread run The horizontal distance between two
consecutive risers or, on an open-riser stair, the
horizontal distance between nosings or the outer
edges of successive treads, all measured perpen-
dicular to the front edges of the nosings or treads.

tread width The dimension of a tread (mea-
sured along the normal line of travel of the stair)
plus the projection of the nosing, if any.

treated lumber Lumber that has been treated
with a preservative, 1 according to standards
of the ASTM, the American Wood Preservers
Association (AWPA), or a similar organization.

treated wood l.See fire-retardant wood. 2.
Wood which has been subjected to a wood
preservative.

treble sash A window having three vertically
sliding sashes, one above the other, each of
which closes a different part of the window; once
used in large houses having very high ceilings;
compare with three-part window.

tredyl Old English term for grees.

1013

tree belt

tree belt A strip between the sidewalk and curb
of a road, planted with grass and sometimes with
shade trees.

tree»dozer An attachment for the front of a
tractor consisting of metal bars and a cutting
blade; used in clearing land of small trees,
bushes, and the like.

tree grate Surrounding a tree trunk set in pave-
ment, a metal grille which is flush with the pave-
ment.

treenail A long pin of hardwood used in timber-
framed houses to secure a joint between two
planks or timbers; also called a trenail or trunnel.

trefoil In an opening, a three-lobed pattern sep-
arated by cusps; see foil.

trefoils

trefoil arch An arch whose inner surface is
struck from three centers; the configuration of
the arch is determined by the position of the
centers of curvature and radii of curvature of the
arcs that are joined.

treillage A trellis support for vines or espaliers.

trellage Same as treillage.

trellis 1 . An open grating or latticework, of
either metal or wood. 2. An arbor or framework
for the support of vines; a treillage.

trellis

trellis molding, trellice molding An orna-
ment, used in buildings of the Norman style,
consisting of a series of overlapping zigzag lines
which produce a trellis-like appearance.

trellis window A casement window, fixed or
hinged, with glazing bars set diagonally to sug-
gest a trellis; also called a lattice window.

tremie A pipe or tube through which concrete
is deposited under water, having at its upper end
a hopper for filling and a bail by means of which
the assembly can be handled by a derrick.

STEEL PIPE

WATER

tremie used in placing concrete under water

tremie concrete Concrete placed by means of

a tremie.
tremie seal Concrete placed under water by

means of a tremie to seal a cofferdam or caisson

so that water may be pumped out.
trenail Same as treenail.
trench 1. A creep trench. 2. A housing, 1.
trench box, trench shield A heavily braced

box of wood or steel which can be moved along

a trench bottom as excavation and pipe laying

1014

triapsidal

proceed; used where the trenches are deep and
not sheathed; also used in lieu of other methods
of sheathing and shoring for shallow excavations
where the sides of the shield can extend from
the trench bottom to the ground surface.
trench brace A device, usually adjustable in
length, for supporting sheeting or other materi-
als used to prevent collapse of the sidewalls of a
ditch or trench.

trench duct A metal trough buried in a con-
crete floor and having removable cover plates
that are level with the top of the floor; used to
carry electric conductors.

trench duct

trench jack A screw jack or hydraulic jack
used as cross bracing in a trench shoring system.

trench shield A shoring system composed of
steel plates and braces which are welded or
bolted together; the shoring system supports the
walls of a trench from the ground level down to
the bottom of the trench; can be moved along as
the work progresses.

tresaunce, transyte, trisantia In medieval
architecture and derivatives, a narrow vestibule
or passageway.

tresse Flat or convex bandelets which are inter-
twined; especially such interlacing ornamenta-
tion used to adorn moldings.

trestle ladder A portable ladder which is self-
supporting, but not adjustable in length; consists
of two sections which are hinged at the top so as
to form equal angles with the base.

trevis See trave, 2.

trial batch Of concrete, a batch which is pre-
pared to establish or check the proportions of
the constituents.

trial pit A small-diameter hole in the ground,
excavated to investigate the nature of the soil
and to determine the distance to bedrock.

triangular arch l.An arch often formed by
two large diagonal stones that mutually support
each other to span an opening; also called a
miter arch. 2. A Mayan arch.

triangular arch

triangular dormer A dormer having a trian-
gularly shaped gable roof.
triangular fret molding See dovetail molding.

triangular pediment A pediment having a
horizontal cornice and slanting sides that meet
in a point at the top so as to form a triangle; also
called an angular pediment.

triangulation A method of surveying in which
the stations are points on the ground which are
located at the vertices of a chain or network of tri-
angles; the angles of the triangles are measured
instrumentally; then the sides are derived by com-
putation from selected sides which are termed
"base lines," the lengths of which are obtained
from direct measurements on the ground.

triapsidal Having three apses, either side by side
or forming a cloverleaf pattern at the sanctuary
end of a church.

1015

triaxial compression test

triaxial compression test A test subjecting a
specimen to a confined hydrostatic pressure and
then to an axial load until failure.

triaxial test A test subjecting a specimen to lat-
eral and axial loads simultaneously.

tribelon In a church, a triple arcade which con-
nects the nave with the narthex.

tribunal In an ancient Roman basilica, a raised
platform for the curule chairs of the magistrates.

tribune l.A slightly elevated platform or dais
for a speaker. 2. The apse of a church.

tricalcium silicate A compound which is a
main constituent of portland cement.

trickle irrigation In landscape architecture,
an efficient means of watering plants or trees by
supplying the water directly to their roots.

triclinium A dining room in an ancient
Roman house, furnished with a low table, sur-
rounded on three sides by couches.

triconch Having apses with semidomes on
three sides of a square chamber; some churches,
chapels, and tombs are built on this plan.

triforium In medieval church architecture, a
shallow passage above the arches of the nave
and choir and below the clerestory; characteris-
tically opened into the nave.

triga A chariot similar to a quadriga but drawn
by three horses.

trigger bolt See auxiliary dead latch.

triglyph The characteristic ornament of the
Doric frieze, consisting of slightly raised blocks of
three vertical bands separated by V-shaped
grooves. The triglyphs alternate with plain or
sculptured panels called metopes. Also see order.

trigonum A mosaic of triangular pieces of mar-
ble, terra-cotta, glass, or other material.

trilateration A surveying method in which the
lengths of all sides of a chain of triangles, poly-
gons, or quadrilaterals (or any combination of
them) are measured with an electronic instru-
ment; the angles then may be computed from
these field measurements.

trilithon Two upright monoliths spanned by a
third, as at Stonehenge.

trilobe arch Same as trefoil arch.

trim l.The visible woodwork or moldings of a
room, such as the baseboards, cornices, casings,
etc. 2. Any visible element, usually of metal or

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1016

tripartite vault

wood, which covers or protects joints, edges, or
ends of another material; the finishings around
fittings and openings, as a door trim, window
trim, etc. 3. The exposed metal appurtenances
of plumbing fixtures, such as faucets, spigots,
exposed traps. 4. The hardware applied to a
door. 5. In the theater, to adjust the vertical
position of any element of scenery or equip-
ment hung in the rigging. 6. Same as trim-
stone. 7. To adjust closely. 8. To fit up and
finish.

trim band A flat piece of metal which is welded
to a side or end of a grating panel and carries no
load; used chiefly to improve appearance.

trim block Same as corner block.

trim bronze A copper-zinc alloy having a
bright finish; usually a commercial bronze (90%
copper) or red brass (85% copper); in strip form
it is used for architectural trim.

trim hardware Decorative finish hardware,
used either to operate functional hardware or to
serve as functional hardware.

trimmed joist A joist, supported by a trimmer,
which has the same cross section as the common
joists.

trimmed opening See cased opening.

trimmed rafter A rafter, supported by a trim-
mer, which has the same cross section as the
common rafters.

trimmer 1 . A piece of timber inserted in a roof,
floor, wooden partition, or the like, to support a
header which in turn supports the ends of the
joists, rafters, studs, etc. 2. A small horizontal
beam, as in a floor, into which the ends of one or
more joists are framed; often named from the
place of use as a hearth trimmer, stair trimmer,
etc. 3. A trimmer arch. 4. Variously shaped
ceramic tile used as bases, caps, corners, mold-
ings, and angles, as necessary to complete an
installation and to satisfy sanitary and architec-
tural requirements.

trimmer arch A nearly flat arch, usually a low-
rise arch of brick; used for supporting a fireplace
hearth; also called trimmer.

trimming Trimming rafters, or trimmers and
trimming joists which form an opening.

trimming joist A joist, supporting a trimmer,
of larger cross section but of the same length as,
and parallel to, the common joists.

Trimmers

Bearing wall

False wall sili

trimming machine See bench trimmer.

trimming piece Same as camber piece.

trimming rafter A rafter, supporting a trim-
mer, of larger cross section but of the same
length as, and parallel to, the common rafters.

trimstone, trim In masonry, the stone used as
decorative members on a structure built or faced
largely with other masonry material, as brick,
tile, block, or terra-cotta; includes sills, jambs,
lintels, coping, cornices, and quoins.

tringle A small square fillet molding or ornament.

tripartite scheme A type of design for a multi-
story commercial building, often associated with
the work of Louis H. Sullivan (1856-1924). The
building's facade is characterized by three princi-
pal divisions: a base consisting of the lowest two
or three stories of the building; a cap, consisting
of one to four stories, at the top of the building,
and a shaft, consisting of the floors between the
base and the cap. Such a building has a flat roof,
projecting eaves, imposing arched or round-
topped windows, vertical strips of windows sepa-
rated by massive mullions, and massive arched
doorways. In Sullivan's designs, the decorative
elements typically consist of highly ornate
friezes with interwoven foliated designs in low
relief (particularly in terra-cotta) that usually
appear in spandrels, 1 and over entrances. See
Sullivanesque.

tripartite vault A vault, covering a triangular
space, which is formed by the intersection of

1017

tripartite window

tripartite vault

three barrel vaults or three expanding vaults;

esp. common in Romanesque buildings.
tripartite window, triple window 1.

Same as three-part window. 2. Same as treble

sash.
triple-hung window A window having three

vertically sliding sashes, each closing a different

part of the window; the weight of each sash is

counterbalanced for ease of opening and closing;

same as treble sash.
triplex cable A cable composed of three indi-
vidually insulated electric conductors, twisted

together and having a common outer protective

covering.
triplex house A house that provides living

quarters for three families, each with a separate

entrance; usually has three stories, with one

apartment on each floor.
tripteral Having three wings or three rows of

columns.
triquetra An ornament composed of three half

circles or ellipses crossed and joined together at

their ends.
trisantia See tresaunce.
tristyle in antis A Classical portico that has

three columns between antae. Compare with

distyle in antis.
tritostile In Hispanic architecture, a loophole.

triumphal arch An arch commemorating the
return of a victorious army, usually in the line of
march during its triumphal procession.

trivet A low support for a surveying instrument

where a tripod cannot be used.
trochilus A cavetto or scotia.

troffer A long recessed lighting unit, usually
installed so that its opening is flush with the
ceiling.

trolley beam An exposed steel beam, attached
to the underside of the structure above; provides
support for and acts as a track for a trolley crane.

Trombe wall A passive solar-energy thermal
storage device used in houses. Consists of a ther-
mal storage wall, usually of masonry or concrete,
8 to 16 in. (20 to 40 cm) thick, that is coated
with a dark heat-absorptive material; and a glass
skin, placed in front of the wall that leaves an air
space K in. to 6 in. (2 cm to 15 cm) between the
wall and the glass. Solar energy that strikes the
glass is absorbed by the wall during the day and
released to the house during the evening.

trompe A piece of vaulting of conical or partly
spherical shape, or resembling one corner of a
cloistered vault.

trompe l'oeil Ceiling and wall paintings that
deceive the eye, creating the illusion of three
dimensions.

trophy A sculptured composition of arms and
armor as an emblem of, or a memorial to, victo-
rious battles or triumphant military figures.

trough A channel used to carry electric con-
ductors.

trough cable tray A continuous cable tray
having slots for ventilation.

troughed roof
trough gutter
trough mixer

trough cable tray

Same as valley roof.
A box gutter.
See open-top mixer.
trough roof See M-roof.
trough urinal A long, narrow urinal designed
for use by several men at the same time;
equipped with a water supply and drain for flush-
ing away the urine.

1018

trowel A flat hand tool having a broad steel
blade; used to apply, spread, and shape plaster
or mortar or to impart a relatively smooth sur-
face to concrete floors and other unformed
concrete surfaces in the final stages of finishing
operations.

trowel

trowel finish A smooth-finished surface pro-
duced by troweling.

troweled joint A mortar joint in a masonry
wall; it is finished by removing excess mortar
with a trowel.

troweling machine A motor-driven device
that operates orbiting steel trowels on radial
arms, which rotate on a vertical shaft; used to
trowel concrete.

truck crane A materials-handling machine
consisting of a crane which is mounted on a
truck-type vehicle to provide mobility and
maneuverability.

truck-mixed concrete Concrete that has
been mixed in a revolving-drum truck mixer.

truck mixer A mobile unit for hauling and
mixing concrete in transit; consists of a rotating
drum (in which the concrete materials are
placed) that is mounted on a truck chassis.

truss chord

true bearing The bearing, 4 of a line in rela-
tion to the local geographic meridian; used in
early descriptions of land boundaries in the US

true horizontal A horizontal plane passing
through a point of vision or a perspective center.

true north The direction from an observer's
position to the geographic north pole.

true soil The upper layer of soil.

trullo A dry-walled rough stone shelter, circular
in plan, with a corbeled domical roof, resem-
bling ancient structures and still used in south-
ern Italy.

trumeau The central support of a medieval
doorway.

trumpet arch A conically shaped squinch, 2.

truncated gable Same as jerkinhead.

truncated roof A gable roof or hipped roof
whose top has been cut off, forming a flat hori-
zontal surface.

trunk lift Same as freight elevator or goods lift.

trunk sewer A sewer which receives many
tributary branches and serves as an outlet for a
large territory; also see main sewer, 2.

trunnel See treenail.

truss A structure composed of a combination
of members (such as chords, 1, diagonals, and
web members), usually in some triangular
arrangement so as to constitute a rigid frame-
work. See king-post truss, plated truss, queen-
post truss, Vierendeel truss; also see bowstring
beam.

UPPER CHORD

WEB MEMBERS

JOINT

BOTTOM
CHORD

truck mixer

truck zoning device On a freight elevator, a
device which permits the operator to move the
car within a limited distance above a landing with
the car door or gate and the hoistway door open.

truss beam Same as trussed beam,
truss blade Same as principal rafter.

truss chord A principal member of a truss,
braced by web members.

1019

truss clip

truss clip A metal component that serves as a
connection between a truss and a wall plate;
resists the forces of wind uplift.

trussed Provided with some form of truss.

trussed beam l.A beam, usually of timber,
reinforced with one or more tie rods. 2. A beam
in the form of a truss; braced by one or more ver-
tical posts supported by inclined rods attached to
the ends of the beam.

trussed joist A joist in the form of a truss, as a
bar joist.

trussed partition l.A framed partition which
is self-supporting at its ends. 2. A partition con-
sisting of a continuously supported frame with
facing or infilling.

trussed purlin A lightweight trussed beam
used as a purlin.

trussed-rafter roof A pitched roof having all
(or selected) opposite pairs of common rafters
triangularly braced.

trussed ridge roof A pitched roof having the
upper ends of its rafters supported by a single
truss, which runs along the ridge.

trussed-wall opening In a framed structure,
any opening in which the framing is trussed to
carry the load above.

truss plate Same as nail plate.

truss rod l.In a truss, a metal rod used as a
member under tension for stiffening. 2. A metal
rod used as a diagonal tie.

try square A square whose legs are fixed at 90°;
serves as a guide for marking lines at right angles
to an edge or surface, as a scale for laying out
work, and as a tool for testing the straightness
and/or squareness of edges, faces, etc.

try square

T»shore A shore having a T-head, 1 .

T-square, tee square A guide used in
mechanical and architectural drawing; consists
of two arms joined together at right angles, like
the letter T; the shorter arm slides along the edge

of the drawing table or drawing board, which
serves as a guide; the longer arm is used to draw
parallel lines or to support triangles for drawing
lines at different angles.

TUB. On drawings, abbr. for tubing.

tube l.A thin-walled pipe. 2. See lamp.

tube-and-coupler scaffold An assembly
consisting of tubing which serves as posts, bear-
ers, braces, ties, and runners, a base supporting
the posts, and special couplers which connect
the uprights and join the various members.

tubeaxial fan 1 . A fan consisting of a propeller
or disk-type wheel within a cylinder; may be
either belt-driven or connected directly to a
motor. 2. A type of axial-flow fan which is simi-
lar to a vaneaxial fan but without downstream
guide vanes. Lower in efficiency than the
vaneaxial fan, but also lower in cost.

tubeaxial fan

tube pile A pipe pile.

tubing Any material in the form of a tube.

tub mixer See open-top mixer.

tubular discharge lamp Any electric-dis-
charge lamp having a straight or curved tubular
bulb.

tubular lock A type of bored lock in which the
bolt is enclosed in a tube.

tubular saw Same as crown saw.

tubular scaffolding Scaffolding which is fab-
ricated of aluminum or galvanized steel tubing,
held together by clamps.

tubular-welded-frame scaffold A sectional
panel or frame metal scaffold substantially built
up of prefabricated welded sections which con-
sist of posts and horizontal bearer with interme-
diate members.

1020

Tudor Revival

tuck A recess in a horizontal mortar joint which
is raked out to provide for tuck pointing.

tuck and pat pointing See tuck pointing.

tuck»in The part of a counterflashing, skirting,
or roofing felt that is inserted into a chase or
reglet in a wall.

tuck pointing, tuck and pat pointing,
tuck joint pointing The finishing of old
masonry joints: the joints are first cleaned out
and then filled with fine mortar which is left
projecting slightly or with a fillet of putty or
lime; also called tuck-and-pat pointing or tuck-
joint pointing.

tuck pointing

Tudor arch A relatively flat, slightly pointed
arch whose inner surface is struck from four cen-
ters; common in the architecture of Tudor
England.

Tudor arch

Tudor architecture The final development
of Perpendicular style architecture during the
reigns of Henry VII and Henry VIII, preced-
ing Elizabethan architecture. Characterized by
Tudor arches, diaperwork, strapwork, labels and
label stops over windows with mullions, ornate
brick chimneys.

Tudor chimney A term occasionally used for
a stepped-back chimney.

Tudor flower An ornament of English Per-
pendicular Gothic buildings; a trefoil flower

Tudor architecture

developed from the upright points of the cross-
ing or the cusps of a foliated arch.
Tudor Revival, Tudor style A term de-
scriptive of a picturesque mode of domestic
architecture prevalent from about 1880 to 1940
and beyond, emulating its Tudor architecture
prototype. Homes in this style, usually asym-
metrical in plan, often were clad in brick, or
stucco in combination with wood; commonly,
false half-timbering; surface ornamentation
consisting of strapwork; steeply pitched gables
with little overhang at the eaves; bargeboards

Tudor Revival

1021

Tudor rose

on the gables; a shingled roof; tall, massive,
elaborate chimneys often with decorative chim-
ney pots atop the chimneys; tall, narrow, leaded
windows; a decorative main entry doorway,
often incorporating a Tudor arch or a round-
topped arch. Compare with Neo-Tudor archi-
tecture, Elizabethan architecture, Jacobethan
architecture.

Tudor rose A conventionalized rose pattern,
usually with five petals, a superposition of white
and red roses, the heraldic emblem of the Tudor
dynasty.

tufa A porous limestone used in masonry con-
struction.

tuff, volcanic tuff A low-density, high-poros-
ity rock; composed of volcanic particles, ranging
from ash size to small pebble size, which are
compacted or cemented together; sometimes
used as building stone or as a thermal insulation
material.

tuft bind The magnitude of the force required
to pull a tuft out of a carpet, according to an
industry-standard test procedure.

tufted carpet Carpet made by punching pile
yarn through a carpet backing material which
has been previously woven; then the pile is cut.

tufted carpet

tulipwood l.A soft, close-textured durable
wood, yellowish in color; used for millwork and
veneer. 2. A rose-colored, very hard wood from
Brazil; esp. used for inlay work.

tumbled Said of a metal surface that has been
cleaned and polished by agitation in a rotating
drum containing a polishing compound.

tumbled-in gable Same as straight-line gable.

tumble home, tumble in An inclination
inward from the greatest breadth of a structure.

tumbler In a lock, the locking mechanism
which detains the bolt until set free by a key.

tumbler switch In electric wiring, a lever-
actuated snap switch.

tumbling See barreling.

tumbling course A sloping course of bricks
that are set perpendicular to a straight-line
gable in Dutch architecture or its derivatives;
such an arrangement provides a better seal
against the penetration of moisture through
the masonry joints than one in which all
courses of bricks within the gable are laid in
horizontal courses up to the peak of the gable.
Where a sloping course of bricks intersects a
horizontal masonry course, the arrangement of
brickwork so formed is called a mouse-tooth
pattern.

tumbling in See tumbling course.

tumulus A mound of earth or stone protecting
a tomb chamber or simple grave; a barrow, 2.

tung oil A drying oil which oxidizes very rapidly,
at almost twice the rate of linseed oil; forms a
hard dry film when used in paints and varnishes;
although "China wood oil" and "wood oil" some-
times are used as synonyms, tung oil never is
extracted from wood.

tungsten-filament lamp See incandescent
lamp.

tungsten-halogen lamp A tungsten-filament
incandescent lamp which is filled with a gas
containing halogens; the envelope, made of
quartz or other material that can be subjected
to high-temperature, is small compared with
standard lamps of equivalent wattage; formerly
known as quartz-iodine lamp.

tungsten inert-gas weld To weld by means of
an electric arc struck between a nonconsumable
tungsten electrode and the workpiece; constant
current across the arc is supplied during the
welding operation.

tungsten steel Steel usually containing 5 to
10% (but sometimes as much as 24%) tungsten
and 0.4 to 2% carbon.

tunnel test An ASTM standard test of the
surface-burning characteristics of a building
material.

tunnel vault A vault having a uniform cross
section everywhere.

turbidimeter An apparatus for the measure-
ment of particle-size distribution of a finely
divided material such as portland cement, based
on successive measurements of the turbidity of a
suspension in a fluid.

1022

turns

turbidimeter fineness The fineness of a
material as measured on a turbidimeter; usually
expressed as the total surface area in square cen-
timeters per gram.

turbine mixer See open-top mixer.

turbulent flow The motion of a fluid in which
local velocities and pressures fluctuate highly
irregularly with time, in contrast to streamline
flow.

turf The upper layer of earth and vegetable mold
in which the roots of grass and other small plants
form a thick cover.

turf sprinkler system Same as lawn sprinkler
system.

turnbuckle A device for connecting and tight-
ening a line, rod, or stay; consists of a right screw
and a left screw which are coupled by means of
a link.

turn button, button A fastener for a window
or door which rotates on a pivot and is attached
to the frame.

turned bolt A machine bolt, ordinarily with a
hexagonal head, whose shank is fabricated to a
close tolerance.

turned drop A hanging wood ornament, formed
on a lathe, but sometimes hand-carved; especially
found in timber-framed early American colonial
houses, often suspended from a second-floor over-
hang, 1. either at the front corners of the facade or
adjacent to the front door. Sometimes simply
called a drop; compare with pendant.

turned work In stone and wood cutting, pieces
having a circular outline, such as columns, balus-
ters, etc.; usually cut on a lathe, although some
shapes are cut by hand.

turning The shaping of objects by means of cut-
ting tools while the material, from which the
objects are made, rotates rapidly on a lathe.

turning bar See chimney bar.

turning gouge Any one of a set of gouges hav-
ing the corners of the bit rounded off; used in
turning.

turning piece l.A piece of board cut to a
curve to guide the mason in turning any small
arch for which no centering is required. 2. Same
as camber piece.

turning vane One of a number of curved fins
which are placed in air-conditioning ductwork
at a point where the duct changes direction;

<fe

r m-

turning vanes

used to promote a more uniform airflow and to

reduce pressure drop.
turn-key job A job in which the contractor

completes all work and furnishing of a building

so that it is ready for immediate use.
turn knob A small doorknob, often oval or

crescent-shaped; used to control the door bolt

from the inside of the door.

turn piece A small doorknob, lever, or the like,
having a spindle attached; used to operate the
dead bolt or a bolt mortised in the door.

turnpike stair Same as spiral stair.

turnstile A barrier which rotates on an axis and
usually is so arranged as to allow the passage of a
person through an opening only in one direc-
tion, one person at a time.

turn tread A tread on a stair where it changes
direction.

turnup That portion of roofing material which
is turned up at any vertical surface.

turpentine, oil of turpentine A volatile liq-
uid obtained by the distillation of the exudation
from certain coniferous trees; once widely used
in paint, it is now replaced by solvents obtained
from petroleum or coal-tar stocks. Also see wood
turpentine.

turret, tourelle A diminutive tower, charac-
teristically corbeled from a corner.

turret step A stone step, triangular in section,
which forms, with other turret steps, a spiral or
solid newel stair. Turret steps are tapered and
have shaped ends which, laid upon each other,
constitute the central column or solid newel.

turriculated Describing a building in which
the characteristic feature is a row of turrets.

turris A tower of a fortification, placed at inter-
vals in the walls of an ancient city or any other
fortified enclosure.

1023

turtleback

turtleback 1. See blistering, 1. 2. In plastering,
a localized condition of checking, 3.

Tuscan order One of the five Classical orders; a
simplified version of the Roman Doric order to
which it is similar, but has fewer and bolder mold-
ings, unfluted columns, a plain frieze, and no
triglyphs; its only decorative details are moldings.

twin axial cable

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Tuscan Revival A term descriptive of late
17 -century architecture that emulates and bor-
rows features from the Tuscan order.

Tuscan Villa style A style somewhat similar
to that of villas in the Italianate style, boxlike in
shape but having a symmetrical plan rather than
an asymmetrical plan and a flat roof; frequently
a square belvedere at the center of the roof; win-
dows often round-headed.

tusk 1 . A beveled shoulder on a tenon to pro-
vide additional strength, the mortise being cut
correspondingly. 2. A stone or brick in toothing.

tusk nailing See toenailing.

tusk tenon A tenon strengthened by having
one or more steps on its lower side; the shoulder
above may be beveled.

twelve-over-twelve See pane.

twin archway An opening having two arch-
ways which are side-by-side.
twin brick Same as double-sized brick.

twin cable A cable consisting of two individu-
ally insulated electric conductors, laid parallel;
either bound together in a common outer pro-
tective covering or attached to each other by
insulation. Also see duplex cable.

twin-filament lamp An incandescent lamp
with two filaments that are wired independently.

twining stem molding A common Norman
molding consisting of a half round entwined by
a stylized tendril.

twin tenons (pi. ) Same as double tenons, 1.

twin-twisted bar reinforcement Two rein-
forcement bars having the same nominal diame-
ter, twisted together.

twist A warped board in which the four corners
of one face are not in the same plane; a spiral
distortion.

"TWIST

twist drill A drill, with one or more helical cut-
ting grooves; used for drilling holes in metal,
wood, etc.

twisted column See wreathed column.

twisted grain Same as interlocked grain.

twisted pair Two insulated electrical conductors,
twisted together without a common covering.

LAY

INSULATED
CONDUCTORS

twisted pair

1024

tympanum

two-and-one-half-story house A two-story
house in which the loft space between the ceil-
ing of the second floor and the roof above is pro-
vided with natural light and ventilation either
by dormers and/or by windows in the gable-end
walls.

two-bay cottage A Cape Cod house having a
facade with two windows on each side of the
front door; also called a full Cape house.

two-by-four A piece of timber, nominally 2 in.
(5 cm) thick by 4 in. (10 cm) wide, but actually
1% in. by 3% in. (4.13 cm by 9.21 cm).

two-centered arch A pointed arch whose
inner surface is struck from two centers; the
shape of the arch is determined by the position
of the centers of curvature and radii of curvature
of the two arcs of circles that are joined; also see
equilateral arch.

two-coat work In plastering, the application
of a first coat (the base coat) followed by a sec-
ond (the finish coat).

two-family house A two-story house having
two separate living quarters, with a separate
entrance for each.

two-hinged arch An arch with hinges at the
supports at both ends.

two-light window l.A window with two
panes. 2. A window which is two panes high or
two panes wide. 3. A gemel window.

two-over-two Descriptive of a double-hung
window having two panes in the upper sash and
two panes in the lower sash; see pane.

two-part adhesive An adhesive that requires
the addition of an accelerator to the resin, in
order to set, e.g., see epoxy.

two-point latch A type of door latching
device; sometimes used where it is necessary to
lock the inactive leaf of a pair of doors at top and
bottom.

two-point suspension scaffold Same as
swinging scaffold.

two-pour system Concrete that is poured at
two different times; compare with monolithic
pour system.

two-room plan A relatively common floor
plan for a simple two-room dwelling in colonial
architecture of New England, the mid- Atlantic
area, and the South. This plan has many varia-
tions but usually consists of an all-purpose main

room (the hall) and an adjacent room (the par'
lor) containing the best furniture and a bed for
the parents. Also see hall-and-parlor plan.

two-stage curing A process in which concrete
products are cured in low-pressure steam,
stacked, and then autoclaved. See cure; auto-
clave.

two-tiered porch A two-story porch, each of
which is virtually identical.

two-way draw Said of a drapery that parts in
the middle and can be drawn to each side.

two-way joist construction Floor or roof
construction in which two mutually perpendicu-
lar systems of parallel beams, in a horizontal
plane, are used to support the floor or roof.

two-way-reinforced footing A footing in
which the reinforcement runs in two directions,
usually perpendicular to each other.

two-way reinforcement Reinforcing bars ar-
ranged in a grid pattern, so that the sets of bars
are at right angles to each other.

two-way slab l.A concrete floor slab in
which the main reinforcement runs in two direc-
tions. 2. A rectangular, reinforced concrete slab
having a span on the long side that is less than
twice the span on the short side.

T-wrench A T-shaped wrench with a handle
having a socket (either fixed or removable)
which fits over a nut or bolt head.

tympanum l.The triangular or segmental
space enclosed between the horizontal cornice
of a pediment and the underside of the raking or
curved cornice above; sometimes decorated with
decorative elements, sculpture, or a window. 2.
Any space similarly marked off or bounded, as
between the lintel of a door and the arch above.

tympanum, 1

102S

TYP

TYP On drawings, abbr. for "typical."
type-DWV tubing A copper tubing which has
thinner walls than other types of copper tubing;
used primarily for drainage, waste, and vent lines.
type-S fuse A fuse contained in a small glass or
ceramic housing, which can be screwed into a
screw-shell socket; it has a window for observing
whether the fuse has been "blown"; available in
three, noninterchangeable sizes (15, 20, and 30
amperes).

type-X gypsum lath A gypsum lath which is
especially manufactured to provide specific fire-
resistant characteristics.

type-S fuse

type-X gypsum wallboard A gypsum wall-
board which is especially manufactured to pro-
vide specific fire-resistant characteristics.

Tyrolean finish A rough plaster finish
obtained by flinging plaster on a wall with a
hand-operated machine.

1026

UBC Abbr. for the Uniform Building Code.
U-bend A pipe expansion bend in the shape of

the letter U.
U-block See lintel block.

U-bolt A rod bent in the shape of the letter U
with threads for nuts on the ends.

U-bolt

U/E Abbr. for "unedged."
U-factor See thermal transmittance.

UFAS Abbr. For Uniform Federal Accessibility
Standards.

U-gauge Same as manometer.

uintahite See gilsonite.

UL Abbr. for Underwriters' Laboratories, Inc.

UL Certified A certificate, issued to a manu-
facturer for one of its products, which indicates
that the product has been tested in the US by
the Underwriters Laboratories, Inc. (UL) and
has met UL requirements.

UL Label An identification affixed to a build-
ing material or component, with the au-
thorization of Underwriters' Laboratories, Inc.,
indicating that the labeled product: (a) has a
rating based on the performance tests of such
products; (b) is from a production lot found by
examination to be made from materials and by
processes essentially identical to those of repre-
sentative products which have been subjected to
appropriate fire, electrical hazard, or other tests
for safety; and (c) is subject to the reexamination
service of UL.

UL Listed See UL Label.

ultimate bearing capacity The average load
per unit of area required to produce failure by
rupture of a supporting soil mass.

ultimate bearing pressure The pressure at
which a foundation sinks without a further
increase in load.

ultimate load See breaking load.

ultimate set The final degree of firmness
attained by a plastic compound after curing,
evaporation of volatile materials, and surface
polymerization.

ultimate shear strength The loading at a
section resulting from the failure of a member in
shear.

ultimate shear stress The stress at a section
which is loaded to its maximum in shear.

ultimate strain The strain at which a material
fails under test.

ultimate strength Of a material in tension,
compression, or shear: the maximum value of
tension, compression, or shear, respectively, that
the material can sustain without failure.

ultimate stress The stress at which a material
fails under test.

ultramarine A blue pigment used in paint;
once obtained from crushed lapis lazuli; now

manufactured synthetically by calcining alu-
minum silicate and sodium sulfide; has good
alkali resistance, but is sensitive to acids.

ultramarine ash The residue of lapis lazuli

after the ultramarine has been extracted; used as
a pigment in paints.

ultrasonic motion detector A motion detec-
tor employing sound waves having a frequency
usually above 20,000 Hz.

ultrasonic soldering A soldering process in
which high-frequency sound waves are transmit-
ted through molten solder to remove undesir-
able surface films from the base metal, thereby
promoting wetting of the base metal with solder;
usually accomplished without the use of flux.

1027

ultrasonic testing

ultrasonic testing A nondestructive method
of testing metal; makes use of very-high-
frequency sound waves to locate flaws in metal.

ultrasonic welding A solid-state welding
process in which the metals are joined by the
local application of high-frequency sound waves
as the work parts are held together under pres-
sure.

ultrasound Acoustic oscillations having a fre-
quency above the high-frequency limit of audi-
ble sound, i.e., above 20,000 Hz.

ultraviolet radiation Electromagnetic radia-
tion at wavelengths immediately below the visi-
ble spectrum, i.e., within the wavelength range
10 to 380 nm. May be classified as: far ultraviolet,
10 to 280 nm; middle ultraviolet, 280 to 315 nm;
near ultraviolet, 315 to 380 nm. Also may be clas-
sified as: ozone-producing, 180 to 220 nm; germi-
cidal, 220 to 300 nm; erythemal, 280 to 320 nm;
black light, 320 to 400 nm. In either method of
classification, there are no sharp demarcations
between the wavelength bands.

umber A naturally occurring brown siliceous
earth, containing hydrated iron oxide with small
amounts of manganese oxide; used as a pigment
in paint; turns red to reddish-brown when cal-
cined, and then is called burnt umber.

umbrage 1 . An open area recessed in the main
body of a building; protected by the ceiling and
floor above. 2. A sheltered, shady space in the
open air, usually relatively small.

umbral In Spanish Colonial architecture, a
lintel.

umbrella roof In French Vernacular architec-
ture of Louisiana, a roof having a single pitch on
each side of a central ridge and covering a galerie
on each side of the house.

umbrella vault A vault that has ribs which fan
out from a central support.

unbonded member A posttensioned, pre-
stressed concrete member in which tensioning
force is applied against end anchorages only, the
tendons being free to move within the element.

unbonded posttensioning In prestressed
concrete, posttensioning in which the tendons
are not grouted to the concrete after being
stressed.

unbonded tendon In prestressed concrete, a
tendon which is not bonded to the concrete.

unbraced frame A structural framework in
which the resistance to lateral load, 1 is provided
by the bending resistance of its structural mem-
bers and their connections.

unbraced length The distance between ends
of a structural member (such as a column) which
are prevented from moving normal to the axis of
the member, by bracing, by floor slabs, etc.

unburnt brick Brick, such as adobe brick, that
is sun-dried, rather than kiln-dried at an ele-
vated temperature; compare with burnt brick.

uncased Said of an arch, doorway, or other
opening that has no frame around it. Uncased
openings are especially found in Spanish Eclectic
architecture and its derivatives.

unclassified excavation An excavation in
which there is a single unit price for removal,
regardless of the proportion of common excava-
tion and rock excavation (compare with classi-
fied excavation).

unconsolidated backfill The non-compacted
material which is in place in a trench.

uncoursed Said of masonry which is not in lay-
ers with continuous horizontal joints, but is laid
irregularly.

uncoursed masonry

unctuarium Same as alipterion.
uncut modillion See modillion.
unde, undee See waved molding.

underbed The base mortar, usually horizontal,
on which a terrazzo topping is applied.

underboarding Boards that are nailed to the
exterior side of the framing of a timber-framed
house to provide a surface on which to fasten an
exterior covering such as shingles or siding.

undercloak 1. In roofing, a course of plain tiles
or slate used under the first course at the eaves.
2. Shingles installed with their thick end over-
hanging the edge of a gable to give a slope to the
tiles laid along the edge. 3. In sheet-metal

1028

underfloor raceway

roofing, that part of the lower sheet that makes up
a seam, or the like.

undercoat 1. A coat of paint applied on new
wood, or over a primer, or over a previous coat of
paint; improves the seal and serves as a base for
the topcoat, for which it provides better adhe-
sion. 2. Any paint which acts as a base for
enamel. 3. Any primer which is colored.

underconsolidated soil deposit A deposit
that is not fully consolidated under the existing
overburden pressure.

undercourse A course of shingles or tiles
which serves as an undercloak, 1,2.

BUILDING RftPER

UNDERCOURSE
^SHEATHING

undercourse

undercroft 1. A vaulted basement of a church
or secret passage, often wholly or partly below
ground level. 2. A crypt.

undercured Said of concrete, a sealant, adhe-
sive, paint, etc., which has not had sufficient
time and/or suitable physical environment to
harden properly.

undercut 1 . In stonework, to cut away a lower
part, leaving a projection above that serves the
function of a drip. 2. To rout a groove or channel
(a drip) back from the edge of an overhanging
member.

undercut door A door without louvers which
is given additional clearance at the floor line to
provide ventilation.

undercut tenon A tenon in which a shoulder
is cut at an angle to the face of the tenon in
order to ensure a tight fit.

underdrain A drain, installed in porous fill, for
drawing off surface water or water from the soil,
as under the slab of a structure.

underdrain

underdrawing Same as torching.

under-eaves course A short course of roof
tiles laid beneath the first course of tiles at the
eaves of the roof.

underfelt 1. A dry sheet of asphaltic felt. See
underlayment, 2. 2. A padding material com-
prised of hair felt, or some combination of felt
and jute, laid directly on the floor, over which
carpet is installed; a type of underlayment.

underfill A depression, on the face of a weld,
which extends below the surface of the adjacent
base metal.

underfloor Same as subfloor.

underfloor conduit system A method of dis-
tributing communications wiring within the floor
of a building. Metal pipes (for housing the wiring)
radiate out to the area served from a serving closet
(or cabinet). Such a system is suitable for installa-
tion in buildings in which the terminal equip-
ment locations are likely to remain fixed.

underfloor conduit system

underfloor heating Heating provided beneath
a finish floor, usually by hot water pipes or electric
heating cables. See radiant heating system.

underfloor raceway A raceway, for carrying
electric conductors, which is suitable for use in a
floor, as one buried within a structural concrete
floor.

1029

undergird

undergird To secure, support, or strengthen a
structure by tying together a number of individual
elements below the soffit of the structure above it.

underglaze decoration A ceramic decora-
tion applied directly on the (bisque) surface of
ceramic ware and subsequently covered with a
transparent glaze.

underground Below grade or ground level, as
underground drain lines or cables.

underground construction See earth-shel-
tered construction.

underground distribution system An
electrical supply system employing underground
structures, cables, and other equipment located
under designated areas along public ways or util-
ity easements; does not include service cables in
the customer's duct.

underground piping Piping in direct contact
with, and covered by, earth.

underground service Said of an element of
building service, such as an electrical cable or a
pipe, that is buried in the ground.

underground structure Any duct, manhole,
subway-type pull box, underground-type enclo-
sure, or vault in which cables, transformers, and
similar items of equipment are installed.

underlay l.Same as underlayment. 2. Same as
carpet underlayment. 3. A layer, such as asphaltic
felt, which isolates a roof covering from the sub-
structure; underfelt.

underlayment 1. A material such as plywood
or hardboard placed on a subfloor to provide a
smooth, even surface for applying the finish.
2. The material, usually No. 15 felt, used to cover
a roof deck before shingles are applied; also called
underfelt. 3. See carpet underlayment.

RESILIENT FLOORING

STRIP

FLOORING

UNDERLAYMENT

SUBFLOOR

underlayment, 1

underlining felt Same as underlayment, 2.

underpinning The rebuilding or deepening of
the foundation of an existing building to provide

additional or improved support, e.g., additional
support required as a result of a new excavation
in adjoining property which is deeper than the
existing foundation.

underpitch groin A groin formed by an
underpitch vault.

underpitch vault, Welsh vault A construc-
tion formed by the penetration of two vaults of
unequal size, springing from the same level.

underpitch vault

under plate See armored front.

undersanded concrete Concrete containing
an insufficient proportion of fine aggregate to
produce optimum properties in the fresh mix-
ture, esp. with respect to workability and finish-
ing characteristics.

undersealing Same as subsealing.

understating felt Same as underlayment, 2.

underslung car frame An elevator car
frame having the fastenings or sheaves for the
hoisting ropes (cables) attached at or below the
car platform.

underthroating The cove of an outside cor-
nice when treated so as to serve as a drip.

undertone 1 . A color modified by an underly-
ing color, as in the effect of glazing over a thin
film of paint. 2. A secondary color of a pigment
which appears when it is diluted with a large
amount of white.

Underwriters' Laboratories, Inc. A non-
profit nongovernment organization sponsored
by the National Board of Fire Underwriters;
classifies, tests, and inspects electric devices
to assure their compliance with the National
Electrical Code.

Underwriters' loop See Hartford loop.

undisturbed sample A sample of soil that
has been obtained by methods in which every

1030

union clip

precaution has been taken to minimize distur-
bance to the sample.
undressed lumber, rough lumber, Brit.
unwrought timber Sawn lumber that has
not been planed.

undue burden A legal term used to indicate
that in the particular case under consideration,
it would be a significantly difficult and/or expen-
sive burden to meet all aspects of the Americans
with Disabilities Act.

undulating molding See wave molding.

undulating tracery See flowing tracery.

undy molding See wave molding.

uneven grain Wood grain in which the growth
rings show an obvious difference between spring-
wood and summerwood; found in ring-porous
hardwoods (such as oak) and softwoods (such as
yellow pine) that have soft, uniform springwood
and hard, dense summerwood.

unfinished bolt A bolt fabricated of low-carbon
steel.

unfired brick A solid masonry unit that has
not been fired in a kiln at a high temperature.

unframed door A door not in a frame, as a
batten door.

ungauged lime plaster Plaster containing no
gypsum; usually composed of lime, sand, and
water.

unglazed tile A hard, dense ceramic tile for
floors or walls; of homogeneous composition
throughout, deriving its color and texture from
the materials of which the body is made and
from the method of manufacture.

unidirectional microphone A microphone
whose response is predominantly from a single
direction.

Uniform Building Code (UBC) 1. A US
national building code, prepared and issued by
the International Conference of Building Code
Officials, 5360 South Workman Mill Road,
Whittier, CA 90601-2294. Also see BOCA
National Building Code. 2. Any model code,
similar to 1, of a country other than the US.

uniform construction index An outline
of building trades and products, separated
into 16 divisions (illustrated under contract
documents), that are arranged by trade and
construction sequence.

Uniform Federal Accessibility Standards

(UFAS) A set of standards concerning acce-
ssibility for the disabled, which are available at
no charge from: US Access Board, 133 1 F Street
NW, Suite 1000, Washington, DC 20004-1 1 11.
Also see Americans with Disabilities Act.

uniform grading A particle-size distribution
of aggregate in which all pan fractions are pres-
ent without a preponderance of any one size or
group of sizes.

uniformity coefficient A coefficient related
to the size distribution of a granular material,
such as sand; obtained by dividing one size of
grain (60% of the grains are smaller than this
size, by weight) by a second size (10% of the
grains are smaller than this size, by weight).

uniform load A load, 1 uniformly distributed
over all or a portion of a structure.

uniform settlement The sinking into the
ground of various parts of a building at the same
rate.

uniform system Coordination of specification
sections, filing of technical data and product liter-
ature, and construction cost accounting, organized
in 16 divisions based on an interrelationship of
place, trade, function, or material.

uninterruptible power system An electric
power system which provides continuity of
power, to the apparatus or appliances being
served, without discernible interruption upon
failure of the normal power supply.

union A pipe fitting, 1 used to connect the ends
of two pipes, neither of which can be turned;
consists of three pieces, the two end pieces (hav-
ing inner threads), which are tightened around
the pipe ends to be joined, and a center piece,
which draws the two end pieces together as it is
rotated, effecting a seal. Also see flange union.

SHOULDER P16C6
GROUND JOINT

COLLAR
THREAD PIECE

union bend See union elbow.

union clip A fitting for interconnecting the
ends of two rainwater gutters.

1031

union elbow

union elbow A pipe elbow, 1 having a union-
type coupling on one end, so that the coupling
end may be connected to the end of a pipe with-
out turning the pipe.

union elbow

lbo

union fitting A union elbow or a union tee.

union joint A pipe joint made with a union.

union tee A pipe tee having a union-type cou-
pling on one end.

union vent Same as dual vent.

unit absorber A sound-absorptive element
which is designed for application on a wall or
ceiling as a single unit; usually part of a spaced
array of similar units.

unit air conditioner Same as room air condi-
tioner.

unitary air conditioner Equipment consist-
ing of one or more factory-fabricated assemblies
designed to perform the functions of air moving,
air cleaning, cooling, and dehumidification; the
assemblies usually include a fan, evaporator or
cooling coil, and a compressor and condenser
in combination; a heating unit also may be
included.

unit construction Same as modular construc-
tion.

unit cooler See room air conditioner.

united inches The sum of the length and
width (expressed in inches) of a rectangular
piece of glass.

United States of America Standards
Institute See American National Standards
Institute.

unit heater A direct-heating, factory-made,
encased assembly including a heating element,
fan and motor, and directional outlet.

unit lock A preassembled lock.

unit masonry See masonry unit.

unit price An amount stated in a contract as
the price per unit of measurement for materials or
services as described in the contract documents.

unit stress The value obtained by dividing the
total stress by the cross-sectional area that is
stressed.

unit substation One or more transformers
which are mechanically or electrically con-
nected to (and coordinated in design with) one
or more switchgear or motor control assemblies,
or combinations thereof.

unit system A curtain wall, 1 composed entirely
of prefabricated units attached to the building
structure.

unit-type vent An opening of relatively small
area (one of a number which are distributed
about a roof according to the occupancy require-
ments), usually having a lightweight metal
frame and housing, with hinged dampers which
may be operated manually or which open auto-
matically in the event of fire.

unit vent See dual vent.

unit ventilator An operable air-inlet damper
which furnishes outdoor air to an interior space;
may be provided with a filter and heating and/or
cooling coils.

unit water content l.The quantity of water
per unit volume of freshly mixed concrete. 2.
The quantity of water on which the water-
cement ratio is based, not including water
absorbed by the aggregate.

universal Descriptive of a door lock, a door
closer, or the like, which can be used on either a
right-hand swing door or a left-hand swing door.

universal motor A motor capable of operating
either on alternating current or on direct current.

unloader A control mechanism for an electric-
motor-driven compressor; controls the pressure
head of the compressor; permits the motor to be
started at low starting torque by removing the
load during this initial period of operation.

unprotected corner Of a slab, a corner hav-
ing no adequate provisions for transfer of load, so
that the corner must carry over 80% of the load.

unprotected metal construction Steel
frame construction in which the framing mem-
bers are not fireproofed.

unreinforced concrete See plain concrete.

unrestrained member A member that is per-
mitted to rotate freely at its points of support.

unseasoned lumber Same as green lumber.

1032

urban renewal

unsound Descriptive of a plaster, slaked lime,
cement, or other mortar which contains parti-
cles that may expand.

unsound knot, decayed knot, rotten knot

A knot that is softer than the surrounding wood.

unsound plaster Hydrated lime, plaster, or
mortar which contains unhydrated particles that
may expand and cause popping or pitting.

unsound wood Same as decayed wood.

unstable equilibrium The condition of a
structure in a state of equilibrium; when a slight
disturbance is applied to the structure and then
removed, the structure does not return to its
original equilibrium position. Compare with sta-
ble equilibrium.

unstable soil Earth material that, because of its
nature or the influence of related conditions,
cannot be depended upon to remain in place
without extra support, such as would be fur-
nished by a system of shoring.

unstiffened member A member (or part of a
member) which is subjected to compressive
forces and is not reinforced in a direction per-
pendicular to the direction along which it will
bend most easily.

unsupported length The distance between

the end supports of a beam.
unwrought timber, unwrot timber British

term for undressed lumber,
up-and-down sash An archaic term for a

rectangular window sash that moves in a vertical

plane; a double-hung window.
up-and-over door An overhead door which

is a single leaf.
UPC Abbr. for "Uniform Plumbing Code."
upfeed system A water distribution system in

which water is supplied and fed upward through

the vertical piping to the highest point of

the system that may be fed, using the available

pressure.
upheaval The upward push of a soil mass.
U-plan The basic plan of a house having a

shape similar to that of the capital letter U.

uplift 1 . The upward pressure on a structure due
to the pressure of the water below. 2. The pres-
sure acting on a material that tends to lift it off
its supports or fasteners as a result of an external
force (for example, wind) acting on it.

uplift capacity A measure of the resistance of

a pile to being pulled out of the ground.
upper capital Same as dosseret.
upping block Same as horse block.

upright l.A vertical piece of timber or stone.

2. A vertical structural member.

upset 1 . To shorten and thicken by hammering,
as a bar of heated metal struck on the end. 2. In
the region of a weld, a localized increase in vol-
ume resulting from the application of pressure.

3. A defect in timber due to a severe blow that
breaks the fibers across the grain.

upset price See guaranteed maximum cost.

upsetting The hot-forging operation by which
the cross-sectional area of a metal bar or rod is
increased locally.

upset 'welding A resistance-welding process in
which the joining of two surfaces is effected by
the heat obtained from the flow of current
through the resistance provided by the area of
contact between the surfaces to be joined; pres-
sure is employed in this process.

upside-down roof Same as inverted roof.

upstage The back part of a stage, away from the
audience.

up stairs Stairs designated to be used for going
up only, as in some schools and institutional
buildings.

upstairs The portion of a house or small build-
ing situated on the floors above the main or
entrance floor.

upstand, upturn The part of a roof covering
that turns up against a vertical surface.

upstanding beam In a concrete floor, a beam
which projects above a concrete slab rather than
below it.

upzoning A change in the zoning classification
of a property from one of lower use to one that is
of higher use; for example, a change from resi-
dential to commercial use.

UR On drawings, abbr. for urinal.

urban area An area which is within the city
limits, or closely linked to it by common use of
public utilities or services.

urban planning See city planning and com-
munity planning.

urban renewal The improvement of slum,
deteriorated, and underutilized areas of a city;

1033

urban sprawl

generally implies improvement realized through
city, state, and, particularly, federal programs,
including the clearance and redevelopment of
slums, the rehabilitation of relatively sound
structures, and conservation measures to arrest
the spread of deterioration.

urban sprawl An unplanned development of
open land, usually on the outskirts of a city.

urea-formaldehyde Same as urea resin adhe-
sive.

urea resin adhesive A dry powder which is
mixed with water before being applied; has high
early strength and good resistance to heat; not rec-
ommended for poorly fitted joints or outdoor use.

urilla Same as volute, 1.

urinal A sanitary fixture equipped with a water
supply and drain for flushing away urine.

urinal (wall hung)

usable floor area The net floor area in a
building after deducting the area occupied by
lobbies, corridors, rest rooms, cafeterias, etc.

usable life See pot life.

USASI Abbr. for American National Standards
Institute.

US Customary Units The system of units
ordinarily used in the US, for example, the unit of
length may be the inch, foot, yard, or mile.

use district An area, designated in the zoning
ordinance of a municipality, within which spec-
ified types of land use are permitted and others
forbidden.

USG On drawings, abbr. for "United States
gauge."

U»stirrup In reinforced concrete construction,
a stirrup, 2 which is U-shaped.

U»tie A U-shaped heavy wire used as a wall tie.

Utility See public utility.

utility pole An outdoor pole installed by a tele-
phone or electric utility company for the support
of conductors and other electric or telephone
equipment.

utility sheet Mill-finished metal sheeting;
available in a variety of sizes suitable for general
building construction.

utility tractor A low- to medium-horsepower
tractor; used primarily for pulling auxiliary
equipment, but also used in construction with
attachments for trenching, dozing, breaking,
etc.

utility tractor

utility vent A vent, 1 which rises well above
the highest water level of a fixture and then
turns downward before it connects to the main
vent or stack vent.

utility window A low-cost hot-rolled steel
window for use in basement areaways, garages,
shops, and the like; usually has a hopper light
over a fixed light.

utilization equipment Any equipment which
utilizes electric energy for mechanical, heating,
lighting, or similar useful purposes.

utilization factor l.The maximum demand
of a system (or part of a system) divided by its
rated capacity. 2. See coefficient of utilization.

U-trap A U-shaped running trap.

U»tube Same as manometer.

U»value See thermal transmittance.

1034

V l.Abbr. for volt. 2. On drawings, abbr. for
valve. 3. On drawings, abbr. for "vacuum."

VIS Abbr. for "vee one side."

VA Symbol for "volt-ampere."

vacuum breaker A backflow preventer which
prevents a vacuum in a water-supply system from
causing backflow.

NORMAL
FLOW

i breake

vacuum circuit breaker An electrical circuit
breaker in which the contacts that perform
switching and interrupting functions are enclosed
in a vacuum.

vacuum concrete Concrete from which
water is extracted by a vacuum process before
hardening occurs.

vacuum lifting The lifting of an object, using
a vacuum as the method of attachment.

vacuum pump A pump which produces a par-
tial vacuum in an enclosed space; may be used to
remove air or steam from a chamber or a system.

vacuum relief valve An automatic valve
that opens and closes a vent for relieving a vac-
uum within a hot water supply system.

vagina The upper part of the pedestal of a termi-
nus, from which the bust or figure seems to arise.

valance 1 . A frame at the top of a window to
conceal the tops of decorative draperies. 2. The
draperies themselves.

valance lighting, pelmet lighting Lighting
furnished by light sources that are concealed and
shielded by a panel parallel to the wall at the top

of a window; may provide lighting in the upward
and/or downward direction.

valley The trough or gutter formed by the inter-
section of two inclined planes of a roof.

valley board In roofing, the board, nailed to
the valley rafter, on which the metal gutter lies.

valley flashing The sheet metal used to line
the valley on a roof.

valley flashing

valley gutter The open gutter in a valley; has

sloping sides and is exposed to view.

valley jack A rafter, shorter than the common
rafters, one end of which is fixed to the ridge,
and the other end to a valley rafter. (See illustra-
tion p. 1036.)

valley rafter In a roof framing system, the
rafter in the line of the valley; connects the ridge
to the wall plate along the meeting line of two
inclined sides of a roof which are perpendicular
to each other. (See illustration p . 1 036.)

valley roof Any pitched roof that has one or
more valleys.

valley shingle A shingle laid next to a valley
and especially cut so that the grain is parallel to
the valley.

valley tile A special roof tile, shaped and laid
to form a valley.

vallum In medieval fortifications, a defensive
wall constructed of earth or stone; may be sur-
mounted by a palisade.

value engineering A discipline of engineering
that studies the relative monetary values of various
materials and construction techniques, including

1035

valve

RIDGE
BOARD

VALLEY
RAFTER

VALLEY
JACKS

valley jack and valley rafter

the initial cost, maintenance cost, energy usage
cost, replacement cost, and life expectancy.

valve A device which regulates or closes off the
flow of a fluid.

valve bag A paper bag for cement, or the like,
which is completely closed except for a self-sealing
paper valve through which the contents are intro-
duced.

valve motor In an air-conditioning system, a
pneumatic or electric device which is used to
control a valve from a remote location.

valve seat The stationary portion of a valve
which, when in contact with the movable por-
tion, stops flow completely.

vamure, vaimure, vauntmure 1. In fortifi-
cations, a false wall; a work raised in front of the
main wall. 2. The alure or walkway along ram-
parts behind the parapet.

vanadium steel An alloy steel containing a
small percentage of vanadium, which raises its
elastic limit and ultimate strength.

Vandyke brown, Cassel brown 1. A very
dark deep brown pigment; usually obtained from
peat or lignite. 2. A synthetic pigment of similar
color.

vane See weather vane.

vaneaxial fan l.A fan consisting of a disk-
type wheel within a cylinder, with a set of air
guide vanes located either before or after the

K VANES

AIRFLOW

vaneaxial fan

wheel; may be either belt-driven or connected
directly to a motor. 2. An axial-flow fan which
incorporates downstream guide vanes. It has a
higher efficiency than any other type of axial-
flow fans.

vaned outlet A register or grille which is
equipped with vertical and/or horizontal
adjustable vanes to regulate the direction of air-
flow.

vane ratio The ratio of the depth of a vane, 2 to
the minimum distance between adjacent vanes.

vanishing point In perspective, a point
toward which a series of parallel lines seem to
converge.

vanity In a bathroom, a combination lavatory
and base cabinet.

1036

vase

VAP On drawings, abbr. for "vapor.''
vapor barrier See vapor retarder.

MOISTURE
BARRIER

VAPOR
BARRIER

vapor barrier

vapor heating system A steam heating sys-
tem which operates at or near atmospheric pres-
sure and returns the condensate to the boiler or
receiver by gravity.

vapor lock The formation of vapor in a pipe
carrying liquids; prevents normal fluid flow.

vapor lock device Any device, such as an ori-
fice or capillary tube, which eliminates or mini-
mizes the collection of vapor in a pipe.

vapor migration The movement of water
vapor as a result of a vapor pressure differential
between a building roof or walls and the outside,
resulting in vapor penetration.

vapor permeance See permeance.

vapor pressure The component of the total
pressure which is caused by the presence of a
vapor, as, for example, by the presence of water
vapor in air.

vapor resistance The resistance to the flow of
water vapor; the reciprocal of permeance.

vapor retarder 1 . A membrane covering the
outer surface of an insulated cold water pipe that
is used to prevent moisture from penetrating the
insulation and reaching the pipe. 2. A layer of
material or laminate used to reduce, appreciably,
the flow of water vapor into a roofing system.

vapor»tight Said of a surface that is enclosed so
as to resist the passage of vapor, often including
the use of a gasket around its periphery.

vapor transmission See water vapor trans-
mission.

vapor vent, vapor relief vent Same as local

vent.
vapour See vapor.

variable air valve (VAV) In an HVAC sys-
tem, a control unit consisting of a metal box
containing damper-position control equipment,
a controller, and a sensor. The box is usually sup-
plied with "primary" air through a duct from the
main distribution system; the output delivers air
to diffusers located in the space being served.

variable-volume air system An air-condi-
tioning system in which the quantity of air sup-
plied to each controlled zone is regulated
automatically, from some preset minimum value
to a maximum value based on the load in each
zone.

variance A written authorization, from the
responsible agency, permitting construction in a
manner which is not allowed by code or other
regulations.

variation order British term for change order.

variegated Said of material or a surface which is
irregularly marked with different colors; dappled.

varnish A clear, unpigmented preparation con-
sisting of resinous matter dissolved in alcohol
(spirit varnish) or other volatile liquid, or in oil
(oil varnish); when applied as a thin coating on
a surface, it dries leaving a hard, smooth, trans-
parent, glossy protective film.

varnish drier See drier.

varnish remover A material, usually liquid,
which softens or dissolves a dry film of varnish so
that it can be removed easily.

varnish stain A varnish which is colored with
a transparent material, leaving a colored coating
on the surface; has less penetrating power than a
true stain.

varved clay Alternating thin layers of silt (or
fine sand) and clay formed by variations in sedi-
mentation during the various seasons of the year,
often exhibiting contrasting colors when par-
tially dried.

vase See bell, 1.

1037

vat

vat See wat.

VAT Abbr. for vinyl-asbestos tile.

vault l.A structure based on the principle of
the arch, often constructed of masonry; typically
consists of an arrangement of arches that cover
the space below; also see barrel vault, cradle
vault, cylindrical vault, fan vault, groined vault,
lierne vault, rampant vault, ribbed vault, seg-
mental vault, sidewalk vault, stilted vault, tun-
nel vault, wagon vault, Welsh vault. 2. A burial
chamber, especially one under a church. 3. An
underground chamber especially designed for
maintaining electrical equipment. 4. A room for
the safekeeping of valuables.

vaulting shaft A colonette in a membered pier
that appears to support a rib in a vault.

vault: 1, barrel vault; 2, intersecting vault; 3, domed vault;
4, stilted vault

vault bay An area of vaulting limited by two

transverse ribs; a severy.
vault door A factory-assembled door with a

frame and hardware which are designed to pro-

tect a storage room against fire and/or burglars.
vaulted 1. Constructed as a vault. 2. Covered

or closed by a vault.
vaulting 1. Vaulted work. 2. Vaults, collec-
tively.
vaulting boss A boss, 1 set at intervals in a

ribbed vault, at a junction between the ribs.
vaulting capital The capital of a pier or

colonette intended to support a vault or a rib

thereof.
vaulting cell One compartment of a vault

which is so planned that one part can be built at

a time.
vaulting course A horizontal course made up

of the abutments or springers of a vaulted roof.

vaulting shaft

vaulting tile A special type of hollow tile,
shaped according to the specific job; used in
vaulting to reduce the weight of the upper parts
of large masses of masonry.

vault light Same as pavement light.

vault rib An arch under the soffit of a vault

that seems to support it.
vault shell The web plates between the ribs of

the vault that are, or seem to be, supported by

them.

vault springing The point where the ribs of a
vault rise upward from an arch impost, capital, or
corbel.

V-beam sheeting Similar to corrugated sheet-
ing but formed of a series of angled flat surfaces
instead of curved surfaces.

V-brick Vertically perforated brick.

V»cut 1. Descriptive of lettering, inscribed in
stone, in which the cuts are acutely triangular.
2. Any saw cut or cut in wood which is V-shaped.

VDT Abbr. for "video display terminal."

VDU Abbr. for "visual display unit."

Vebe apparatus An apparatus for measuring
the consistency of freshly mixed concrete; deter-
mined from a measurement of the time for a
vibrated, truncated cone to be transformed into
a right cylinder.

1038

veneered wall

vee- See V-.

vee-joint See V-joint.

vegetable black Same as lampblack.

vegetable glue A water-based treated starch
which spreads easily; has low strength and poor
moisture resistance; esp. used for hanging wall-
paper.

vegetable oil An oil extracted from vegetable
matter; esp. castor, linseed, safflower, soya, and
tung oil; used in paints and plastics.

vehicle In a paint, the liquid in which the pig-
ment is dispersed.

vehicular way A route intended for vehicular
traffic, such as along a street.

vein cut Quarried stone that is cut perpendicu-
lar to its natural bedding plane.

velarium The awning sheltering the seats in an
ancient Roman theater or amphitheater from
sun and rain.

vellum glaze A semimatte glaze having a
satin-like appearance.

velocity head Of a fluid moving with a given
velocity: the equivalent height through which a
body must fall to acquire the same velocity.

velodrome A stadium or arena with a banked
track designed for bicycle or motorcycle racing.

velum Same as velarium.

velvet carpet Carpet woven on a loom in a
manner similar to cloth; the layers of pile yarn
loops are bound to a layer of jute; then the pile is
cut, forming a smooth surface.

as a facing that is bonded to a less attractive
wood, or as facing on a fire-rated material. 2. An
outside wall facing of brick, stone, etc.; provides
a decorative, durable surface but is not load-bear-
ing. 3. See brick veneer.

veneer base A type of gypsum lath sheeting,
usually 4 ft (121.9 cm) wide, available in various
thicknesses and lengths; has a gypsum core with
a special paper facing which permits veneer plas-
ter to be applied.

veneered construction A reinforced concrete
or steel framework (or wood construction) which
is faced with a thin external layer of marble, struc-
tural glass, or some other facing material.

veneered construction (two types)

veneered door A door made up of either a

solid or a hollow core and veneer faces.
veneered plywood Plywood which is faced

with a decorative wood veneer.

velvet carpet

vendor l.A person or organization who fur-
nishes materials or equipment not fabricated to a
special design for the work, 1 . Also see supplier.
2. One who sells or contracts to sell real prop-
erty. Also see purchaser.

veneer 1 . A thin sheet of wood that has been
sliced, rotary-cut, or sawn from a log; often used
as the top one of several layers of plywood serving

FACE
VENEER

CROSSBANDING
BACK VENEER

veneered plywood

veneered wall A wall of veneered construc-
tion. For example, a wall having a facing of brick
or some other weather-resistant noncombustible
material that is securely attached to the backing,
but not bonded to it.

1039

veneer plaster

veneer plaster A one-component or two-
component mill-mixed gypsum plaster; applied
to a maximum overall thickness of about ¥n in.
(0.25 cm); has good bond, high strength; is
rapidly installed.

veneer tie A wall tie designed to hold a veneer
facing to the wall construction.

veneer wall, veneered wall Any wall hav-
ing a facing which is attached, but not bonded,
to the wall. Also see brick veneer.

veneer wall tie A strip of metal used to tie a
facing veneer to the wall which it covers.

Venetian, Venetian mosaic A type of ter-
razzo topping containing large chips.

Venetian arch A pointed arch in which the
intrados and extrados are farther apart at the
peak than at the springing line.

Venetian blind 1. A blind, 1 made of thin hori-
zontal slats or louvers, so connected as to overlap
one another when closed, and to show a series of
open spaces for the admission of light and air
when open; esp. a hanging blind of which the
slats are held together by strips of webbing or
other flexible material. 2. Adjustable exterior
slatted shutters.

Venetian dentil A type of dentil; a notched
ornamentation consisting of a series of cubical
projections alternating with sloped surfaces.

Venetian door A door having a long narrow
window at each side which is similar in form to
that of a Venetian window.

Venetian Gothic Same as High Victorian
Gothic.

Venetian mosaic See Venetian.

Venetian motif See Palladian motif.

Venetian red A red pigment having a high red
iron oxide content.

Venetian window, Palladian window, Dio-
cletian window A window of large size,
characteristic of neoclassic styles, divided by
columns or piers resembling pilasters, into three
lights, the middle one of which is usually wider
than the others, and is sometimes arched.

vent 1. A pipe installed to provide a flow of air
to or from a drainage system or to provide a cir-
culation of air within such system to protect trap
seals from siphonage and back pressure. 2. A vent
connector. 3. A vent system. 4. A ventilator, 3.

5. A stack designed to allow moisture vapor or
other gas from inside a building or building sys-
tem to escape into the atmosphere. 6. See cavity
vent.
VENT. On drawings, abbr. for "ventilate."
vent cap A fitting which provides protection
for the open end of a vent stack, soil stack, or
waste stack; prevents objects from being dropped
down the stack.

vent cap

vent connector A metal pipe which connects
the exhaust of a gas appliance to a chimney.

vented form Formwork constructed to retain
the solid constituents of concrete but to permit
water and air to escape.

vented wall furnace A recessed heater; a
self-contained vented appliance designed for
incorporation in, or permanent attachment to,
the structure of a building.

vent extension A pipe from the uppermost
drainage branch connection through the roof to
the atmosphere.

vent flue Same as vent, 1.

vent header A header, 4 (i.e., a horizontal vent
pipe) that connects the tops of vent stacks or stack
vents at the header; a single vent pipe extends
from the header to the open air above the roof.

ventilated ceiling A ceiling containing a mul-
tiplicity of air outlets covering a significant part
of the ceiling area and acting as a whole (not as
individual units).

ventilating bead See draft bead.

ventilating brick A brick with holes in it to
provide for air passage.

1040

vent stack

Roof

-Vent terminal

"TT

~Vent header

^4/

Stack vents

vent header

ventilating eyebrow Same as eyebrow window.

ventilating jack A sheet-metal hood over the
inlet to a vent pipe to increase the flow of air
into the pipe.

ventilation The process of supplying or remov-
ing air, by natural or mechanical means, to or
from any space; such air may or may not have
been conditioned.

ventilation pipe Same as vent pipe.

ventilator 1. In a room or building, any device
or contrivance used to provide fresh air or expel
stale air. See ridge ventilator, roof ventilator,
and slit ventilator. 2. A framework, pivoted on
hinges, in which panes of glass are set; a pivoted
sash. 3. Same as ventlight.

ventilator frame An assembly consisting of
two rails and two stiles, designed to support the
glass of a pivoted sash (ventilator, 2).

venting The replacement of air that is carried
out from a stack into the building drain and
sewer by waste.

venting loop Same as loop vent.

ventlight, night vent, vent sash In a win-
dow, a small operable light (pane) with hinges
along its upper edge, so that it may be swung
open to provide ventilation without opening the
entire sash.

vent pipe 1. A pipe, attached to drainage pipes
near one or more traps, which leads to outside
air (e.g., a connection to a vent stack); admits

VENT PIPE
-STACK VENT

SOIL PIPE
3-

\ LAVATORY

-SOIL STACK

vent pipe, 1

vent pipe, 2

air or takes air away from the drainage pipes and
prevents the trap seals from being broken by air
pressure within the drainage pipes. 2. A pipe
connecting a space on the interior of a building
with outside air.
vent sash Same as ventlight.

vent stack, main vent A vertical vent pipe
installed primarily for the purpose of providing

r^s

VENT
STACK-

H0R1ZONTAL BRANCH

vent stack

1041

vent system

circulation of air to or from any part of the
building-drainage system, and to prevent the
water seals of the traps from being broken by
siphonage.

vent system A gas vent or chimney, together
with a vent connector, that forms a continuous
unobstructed passageway from gas-burning
equipment to the outdoor air for the purpose of
removing vent gases.

veranda, verandah An open porch or bal-
cony, usually covered, that extends along the
outside of a house or other building; sometimes
called a piazza; also see galerie and galena.

verd antique, verde antique A dark green
serpentine rock marked with white veins of cal-
cite; takes a high polish; used for decorative pur-
poses since ancient Rome; sometimes classed as
a marble.

verdigris, aerugo The greenish blue corrosion
on copper that has been exposed to air for a long
period of time; used as a pigment.

verge 1. The edge projecting over the gable of a
roof. 2. The shaft of a column; a small ornamen-
tal shaft.

vergeboard Same as bargeboard.

verge course See barge course.

verge fillet A strip of wood nailed to the roof
battens over a gable; covers the upper edges of
the gable walls.

verge rafter See barge couple, 2.

verge tile A tile at the edge of a roof, project-
ing over the gable; usually somewhat wider than
the other tiles on the roof.

vermiculated Ornamented by irregular wind-
ing, wandering, and wavy lines, as if caused by
the movement of worms.

vermiculated mosaic An ancient Roman
mosaic of the most delicate and elaborate char-
acter; the Roman opus vermiculatum; the
tesserae are arranged in curved, waving lines, as
required by the shading of the design.

vermiculated work l.A form of masonry
surface, incised with wandering, discontinuous
grooves resembling worm tracks. 2. A type of
ornamental work consisting of winding frets or
knots in mosaic pavements, resembling the
tracks of worms.

vermiculite A natural mica expanded by heat
(i.e., exfoliated) to form lightweight thermal insu-

vermiculated work

lating material, used in the expanded state alone
as loose-fill or as aggregate with other materials.

vermiculite concrete Concrete in which the
aggregate consists of exfoliated vermiculite.

vermiculite plaster A plaster using very fine
exfoliated vermiculite as the aggregate; used as a
fire-retardant covering on steel beams, concrete
slabs, etc.

vernacular architecture Architecture that
makes use of common regional forms and materi-
als at a particular place and time; sometimes
includes strong ethnic influences of an immi-
grant population; usually modest, unassuming,
and unpretentious, and often a mixture of tradi-
tional and more modern styles or a hybrid of sev-
eral styles. Houses are often owner-built by
people familiar with local materials, regional cli-
matic conditions, and local building customs and
techniques, as described under folk architecture.

vernier An auxiliary scale sliding against and
used in reading a primary scale; the total length
of a given number of divisions on a vernier is
equal to the total length of one more or one less
than the same number of divisions on the pri-
mary scale; makes it possible to read a principal
scale much closer than one division of that scale.

versurae The side wings of the stagehouse of an
ancient Roman theater.

VERT On drawings, abbr. for "vertical."

vertical l.Any upright member, as in a truss.
2. The direction of gravity, at right angles to the
horizon.

vertical angle An angle in a vertical plane.

vertical bar An upright muntin.

vertical blind A blind, 1, in a window, com-
prised of thin vertical slats that can be adjusted
to darken a room or block a view.

1042

vertical slip form

vertical bond Same as stack bond.

vertical circle A graduated disk mounted on
an instrument in such a manner that the plane
of its graduated surface can be placed in a verti-
cal plane.

vertical curve A smooth parabolic curve in
the vertical plane used to connect two grades of
different slope to avoid an abrupt transition in
passing from one to the other.

vertical cut Same as plumb cut.

vertical diaphragm Same as shear wall.

vertical exit Any path of travel such as a stair,
ramp, escalator, or fire escape, serving as an exit
from the floors above or below the street floor.

vertical-fiber brick A type of paving brick
which is cut with a wire in manufacture; laid
with wire-cut side facing up.

vertical firing In a furnace, burners (gas, oil, or
pulverized-coal) which are arranged so that the
fuel is discharged vertically — either upward from
burners below or downward from burners in the
top.

vertical-grained See edge-grained.

vertical-log cabin A log cabin whose exterior
logs are oriented vertically rather than horizon-
tally; this construction requires more time and
greater skill than if the logs are oriented hori-
zontally, as is usual. For an example of construc-
tion in which vertical logs are driven in the
ground, see poteaux-en-terre; also see poteaux-
sur-sole, a somewhat similar construction where
the vertical logs rest on a wood foundation.

vertically pivoted window, reversible
window A window having a sash (ventila-
tor, 2) which pivots (usually 360°) about a verti-
cal axis at or near its center; when opened, the

outside glass surface is conveniently accessible

for cleaning.
vertical meeting rail See meeting stile.
vertical opening An opening through a floor,

roof, or other horizontal surface.
vertical pipe Any pipe or fitting which makes

an angle of 45° or less with the vertical.

vertical plane A plane at right angles to the
horizontal plane and within which angles and
distances are observed.

vertical-plank door Same as battened door.

vertical pump A long, slender multistage

pump designed primarily to pump water from

deep wells.
vertical riser diagram Same as riser diagram.
vertical sash Same as vertical sliding window.
vertical saw A saw which operates in a vertical

plane.
vertical section A drawing depicting a view

that would be seen if a vertical plane were cut

through the object observed.
vertical siding A type of exterior wall cladding

attached to the wall in a vertical orientation;

most often consists of wide, upright boards that

have a tongue along one vertical edge and a

groove along the opposite edge; also see siding

and tongue-and-groove joint.

vertically pivoted window

vertical siding

vertical sliding window A window having
one or more sashes which move only in the ver-
tical direction; they are held in various open
positions by means of friction or a ratchet device
instead of being supported by sash balances or
counterweights.

vertical slip form A form which is jacked ver-
tically and continuously during the placing of
concrete.

1043

vertical spring-pivot hinge

vertical spring-pivot hinge A spring hinge
for a door which is mortised into the heel of the
door; the door is fastened to the floor and door
head with pivots.

vertical spring-pivot hinge

vertical tiling Tile which is hung vertically on
the face of a wall; provides protection against
moisture.

vertical transportation services Elevators,
escalators, and other mechanical devices in a
building for transporting people or goods from
one level to another.

vertical tray conveyors A vertical convey-
ing system which is capable of carrying trays or
boxes.

vertical-vision-light door Same as narrow-
light door.

very-high-output fluorescent lamp A
rapid-start fluorescent lamp designed to operate
on higher current than a high-output fluorescent
lamp, providing a corresponding increase in light
flux (lumens) per unit length of lamp.

vesica piscis A long and sometimes pointed
oval form; a mandorla.

vesica piscis

vestiary A room for the keeping of vestments,

garments, or clothes; a wardrobe.
vestibule An anteroom or small foyer leading

into a larger space.
vest-pocket park A park which is built on a

small plot of land.

vestry, revestry A chamber in a church, near
the sanctuary, for the storage of the utensils used
in a service and for the robes of the clergy and
choir.

VG Abbr. for "vertical grain."

V-groove See quirk, 2.

V-gutter A valley gutter.

via de crujia The enclosed passageway
between the high altar and choir of a Hispanic
cathedral.

vibrated concrete Concrete compacted by
vibration during and after placing.

vibrating pile driver Same as sonic pile
driver.

vibrating roller A roller which has a motor-
driven eccentric for compacting soils.

vibrating screed A machine designed to level
a freshly poured concrete slab and also to act as a
vibrator.

vibration As applied to concrete, see concrete
vibration.

vibration isolator A resilient support for ma-
chinery, piping, ductwork, etc., which may act as a
source of vibration; designed to reduce the amount
of vibration transmitted to the building structure.

vibration isolator (coil-spring type)

vibration isolator (bonded-elastomeric type)

vibration limit The time required for fresh
concrete to harden sufficiently to prevent its
becoming mobile when subjected to vibration.

vibration meter An apparatus for measuring
the displacement, velocity, or acceleration of a
vibrating body.

1044

viga

vibration mount Same as vibration isolator.

vibration service lamp An incandescent
lamp, having a tungsten filament, which is
designed to withstand mechanical vibration to a
greater degree than a general service lamp.

vibrator An oscillating, power-operated ma-
chine used to agitate fresh concrete so as to elim-
inate gross voids including entrapped air (but
not entrained air) and to produce intimate con-
tact with form surfaces and embedded materials.

vibrator

vicarage In England, the home or residence of
a vicar.

Vicat apparatus A penetration device used in
the testing of hydraulic cements and similar
materials to measure their consistency and their
initial and final setting times.

vice

see vis.

vice stair A screw stair.

Vickers number A numerical rating for the
hardness of a metal; measured by applying a
known force to an inverted pyramid-shaped dia-
mond placed on the surface of the metal, and
then measuring the area of indentation and the
depth of penetration.

Victorian architecture l.The Revival and
Eclectic architecture in 19th century Great
Britain, named after the reign of Queen Victoria
(1837-1901); also its American counterpart.
Many architectural historians avoid the term
Victorian architecture, considering the adjective
"Victorian" merely as descriptive of an age that
encompassed a number of specific exuberant,
ornate, and highly decorative architectural
styles. 2. A loose term that sometimes covers
three picturesque phases of architecture in
America: Early Victorian (1840-1860), High Vic-
torian (1860-1880), and Late Victorian (1880-
1890) and beyond; the adjective "Victorian" is
descriptive of an age that encompassed a number
of specific exuberant, ornate, and highly decora-
tive architectural styles, such as High Victorian

Italianate (1860-1885), High Victorian Gothic
(1860-1890), Second Empire style (1855-
1890), Stick style (1860-1885), Shingle style
(1880-1890), Victorian Romanesque (1870-
1900), Gingerbread Folk architecture (1870-
1910), and Queen Anne style (1870-1910).
The adjectives Victorian or High Victorian are
sometimes applied to Gothic Revival and Ital-
ianate style to indicate their later, more detailed,
and more elaborate phases.

Victorian Gothic Same as High Victorian
Gothic; also see Gothic Revival.

Victorian Queen Anne style See Queen
Anne style.

Victorian Romanesque An ornate out-
growth of the Richardsonian Romanesque style
from which it differs both in the use of color and
in the texture of masonry, and in being less exact
in adapting Romanesque style forms; popular
from about 1870 to 1900; usually characterized
by: rock-faced stone or decorative stonework,
often polychromed; brick of different colors;
panels of terra-cotta; semicircular arches or com-
pound arches similar to those in the Roman-
esque style; pilastered arcades at ground level;
steeply pitched wall gables; multicurved para-
pets; window heads framed by masonry arches;
doors set within concentric rounded masonry
arches or with voussoirs of more than one color.

Vierendeel truss, Vierendeel girder An
open-web truss having verticals which are
rigidly connected to the top and bottom chords
but without diagonals.

viga In Spanish Colonial architecture and its
derivatives, a log that has been stripped of its
bark and unhewn; used as one of a number of
roof beams spanning the width of a building
between opposite adobe walls; usually evenly

t 1

vigas

1045

vignette

spaced along the length of the walls; often round
in cross section. Typically, the vigas are overlaid
with small straight saplings that are covered by a
reed matting; this combination supports a roof of
dried mud or adobe.

vignette See vinette.

vihara A Buddhist or Jain monastery in Indian
architecture.

Viking style See Dragon style.

villa 1. In the Roman and Renaissance periods,
a country seat with its dwelling, outbuildings,
and gardens, often quite elaborate. 2. In modern
times, a detached suburban or country house of
some pretension.

village green An open space or public park,
once traditionally located at the center of a vil-
lage; still found in many towns today; also see
common.

Villa style See Italianate style.

vimana l.A Hindu temple, mainly of the
Deccan and southern India. 2. The sanctuary
in such a temple containing a cell in which a
deity is enshrined.

vine A plant whose stem is not self-supporting.

vinette, trayle, vignette An ornament of run-
ning vine scrolls with grape clusters and leafwork.

vinyl A thermoplastic compound made from
polymerized vinyl chloride, vinylide chloride, or
vinyl acetate; includes some plastics made from
styrene and other chemicals.

vinyl-asbestos tile A resilient, semiflexible
floor tile; composed of asbestos fibers, ground
limestone, plasticizers, pigments, and a poly-
vinyl chloride resin binder; has good wearing
qualities, high grease resistance, and relatively
good resilience.

vinyl composition tile A resilient floor cov-
ering which is composed of a binder (one or
more resins, such as vinyl chloride, compounded
with suitable plasticizer and stabilizers) with
fillers, and pigment.

vinyl flooring A resilient floor covering in
sheet or tile form composed of a vinyl plastic
binder, mineral fillers, and pigment.

vinyl paint A water-based paint containing
vinyl.

vinyl tile A floor tile composed principally of
polyvinyl chloride but also containing mineral
fillers, pigments, plasticizers, and stabilizers; does
not require waxing; usually set in mastic over a
wood or concrete subfloor.

Virginia house A comparatively simple tim-
ber-framed wood house used during the 17 th
century, originating in the Chesapeake Bay area
of the Commonwealth of Virginia; supported by
posts sunk in the ground rather than by a foun-
dation. The exterior walls were covered with a
wall cladding of hand-split clapboards, which
provided additional structural strength.

Virginia I-house An I-house often found in
southern US; usually has a relatively low-pitched
roof, a central dormer, and a raised foundation.

Virginia rail fence Same as zigzag fence.

vis, vice, vise A spiral staircase generally of
stone, whose steps wind around a central shaft or
newel; a screw stair.

viscometer A device for determining viscosity;
esp. used to measure the viscosity of slurries,
including fresh concrete.

viscosimeter Same as viscometer.

viscosity The internal frictional resistance
exhibited by a fluid in resisting a force which
tends to cause the liquid to flow.

viscous filter A filter for cleaning air; dirt, car-
ried by the air, impinges on a surface covered
with a viscous fluid or oil, to which the dirt par-
ticles adhere.

vise l.A gripping tool, fixed or portable, used to
hold an object firmly while work is performed on
it; has movable jaws, similar to a clamp, which are
brought together by a screw or lever. 2. See vis.

JAWS

ANVIL

si in:

SWIVEL

vise, 1

1046

V-notch

visibility l.The quality or state of being per-
ceivable by the eye. 2. The distance at which an
object out-of-doors can be just perceived by the
eye. 3. The size of a standard test object, observed
under standardized viewing conditions, which
has the same threshold as the given object.

vision cloth A curtain on the stage of a theater
which has a gauze or scrim inset; if an actor (or
scene) behind the inset is illuminated, he is vis-
ible to the audience as one appearing in a vision.

vision light 1. A window glazed with clear glass
for viewing. 2. A viewing window in a fire-rated
door; usually wire glass must be used and the
dimensions of the glass are limited by code.

vision-light door A door having one small
viewing window in the upper portion only, usu-
ally located on the vertical center line of the door.

visionproof glass See obscure glass.

visita In Spanish Colonial architecture in the
American Southwest, a chapel in which services
were conducted by a visiting padre because it
served too few people to have its own priest.

visor roof A pent roof, 1 that extends only
along one face of a building, usually the facade.

vista A usually unobstructed view into the dis-
tance; often given scale by the receding perspec-
tive of a road or a row of trees.

visual acuity A measure of the ability to dis-
tinguish fine details; the reciprocal of the angu-
lar size of critical detail which is just large
enough to be seen.

visual angle The angle which an object or
detail subtends at the point of observation; usu-
ally measured in minutes of arc.

visual field The angular extent of space which
can be perceived when the head and eyes are
kept fixed.

visual inspection Inspection by examination
without the use of testing apparatus.

visual photometer See photometer.

VIT On drawings, abbr. for "vitreous."

vitreous Descriptive of that degree of vitrifica-
tion evidenced by low water absorption; gener-
ally signifies less than 0.3% absorption (except
for floor and wall tile and low-voltage electrical
porcelain, for which it signifies less than 3.0%
absorption).

vitreous china A ceramic that is glazed, vitri-
fied, and extremely smooth.

vitreous enamel See porcelain enamel,
vitreous sand Same as smalt.
vitreous tile Same as glazed tile.

vitrification Of a clay product, the condition
resulting when kiln temperatures are sufficient
to fuse grains and close the surface pores, making
the mass impervious.

vitrified Same as vitreous.

vitrified brick Brick which has been glazed so

that it is impervious to water and has a high

resistance to chemical corrosion.

vitrified-clay pipe Pipe manufactured of an
earthenware material which is glazed so that it is
impervious to water and has a high resistance to
chemical corrosion; in the US, sometimes used for
house sewer pipes and underground drainage.

vitrified sewer pipe See vitrified-clay pipe.

Vitruvian scroll, Vitruvian wave A com-
mon motif in classical ornament: a series of
scrolls connected by a wave-like band; also
called a wave scroll or running dog.

Vitruvian scroll

vivarium An enclosure for raising animals and

keeping them under observation.
V-joint, vee-joint A recessed masonry joint,

formed in mortar by the use of a V-shaped metal

tool.
V-notch A notch, in the shape of the letter V,

cut into a log or timber near one of its ends;

V-notch

1047

void-cement ratio

forms a rigid joint when mated with another
appropriately notched log or timber in log-cabin
or log-house construction.

void-cement ratio The ratio of volume of air
plus water to the volume of cement.

void ratio In a soil mass, or the like, the ratio of
the volume of the void space to the volume of
the solid particles.

voids l.In cement paste, mortar, or concrete,
the air spaces between and within pieces of
aggregate. 2. Volumes of air not occupied by the
solid material of a soil; voids usually are partially
filled with air and water.

void- solid ratio The proportion of window
and door openings to wall surface area in the
exterior wall of a building.

VOL On drawings, abbr. for "volume."

volatile Descriptive of a substance which passes
off easily as a gas or vapor, evaporating quickly.

volatile thinner A thinner which evaporates
especially rapidly, reducing the viscosity of a
paint, adhesive, etc., without altering its other
properties.

volcanic tuff See tuff.

volt In electric systems the unit of potential dif-
ference or electromotive force; when applied
across a resistance of 1 ohm, will result in a cur-
rent flow of 1 ampere.

voltage Of an electric circuit, the greatest root-
mean-square difference of potential between any
two conductors of the circuit.

voltage drop The difference in electromo-
tive force between any two points in an electric
circuit.

voltage regulator An automatic electric con-
trol device whose output provides a constant
voltage supply, even though the line voltage at
its input may vary.

voltage-to-ground l.In a grounded electric
circuit, the voltage between the given conductor
and that point of the circuit which is grounded.
2. In an ungrounded circuit, the greatest voltage
between the given conductor and any other con-
ductor in the circuit.

voltage transformer A transformer whose
primary is connected to a medium-voltage
source and whose secondary is connected to a
load at lower voltage.

voltmeter An instrument for measuring the
voltage drop between any two points in an elec-
tric circuit.

volume batching Measuring the constituent
materials for mortar or concrete by volume,
rather than by weight.

volume method A method of estimating
probable total construction cost by multiplying
the adjusted gross building volume by a prede-
termined cost per unit volume.

volume strain See bulk strain.

volumeter l.An instrument for measuring the
volume of a gas or liquid. 2. A type of flushometer.

volumetric absorption The ratio of the vol-
ume of a liquid, that is absorbed by a mass to the
volume of the mass.

volume yield See yield, 1.

voluntary standard A standard with which
there is no obligation to comply, either legally or
de facto .

volute l.A spiral scroll, as on Ionic,
Corinthian, or Composite capitals, or on con-
soles, etc. 2. A stair crook having an easement
with a spiral section of stair rail.

volute, 1

vomitorium A vomitory in an ancient Roman

theater or amphitheater.
vomitory An entrance or opening, usually one

of a series, which pierces a bank of seats in a

theater, stadium, or the like.
voussoir A wedge-shaped masonry unit in

an arch or vault whose converging sides are

cut as radii of one of the centers of the arch or

vault.
voussoir brick Same as arch brick.
VP On drawings, abbr. for vent pipe.
V-roof A peaked roof, gable roof, or the like.
VS l.On drawings, abbr. for "versus." 2. Abbr.

for vent stack. 3. Abbr. for "vapor seal."

1048

vyse

m-x

V-shaped joint, 1

vomitories

voussoirs

V-shaped joint, V-joint, V-tooled joint 1 . A

horizontal V-shaped mortar joint made with a
steel jointing tool; very effective in resisting the

penetration of rain. 2. A joint formed by two
adjacent wood boards, in the same plane, which
have faces with chamfered edges.

V»tool A gouge with a V-shaped cutting edge;
see also parting tool.

V-tooled joint See V-shaped joint.

vug A pit-like natural cavity in stone, usually
between a small fraction of an inch and a few
inches in diameter; may be lined with crystals or
layers of mineral materials; most common in
dolomite, limestone, and marble.

vulcanization An irreversible process during
which a rubber compound, through a change in
its chemical structures, becomes less plastic,
more resistant to swelling by organic liquids,
and more elastic (or the elastic properties are
extended over a greater range of temperature).

vys See vis.

vyse See vis.

1049

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W l.Abbr. for watt. 2. On drawings, abbr. for
"west." 3. On drawings, abbr. for "width."

W/ On drawings, abbr. for "with."

WAF Abbr. for "wiring around frame."

waferboard A rigid building board made of
wood chips bonded together with an adhesive
resin.

wafer check valve (WCV) See butterfly
check valve.

waffle See dome, 2.

waffle floor See waffle slab.

■waffle slab A concrete slab which is reinforced
by ribs in two directions, forming a waffle-like
pattern.

Wagner fineness The fineness of a material,
as determined by the Wagner turbidimeter appa-
ratus and procedure; for a material such as port-
land cement, expressed as the total surface area
in square centimeters per gram.

■wagon ceiling A ceiling of semicylindrical
shape, as a barrel vault.

■wagon drill An assembly for positioning and
handling a pneumatic drill; consists of a mast
with a carrier for the drill and a wheeled carriage
for moving and positioning the unit.

wagon»headed Having a continuous round
arched vault or ceiling, as in barrel vaulting.

wagonhead vault A barrel vault.

wagon roof See barrel roof, 1.

wagon shed, wagon house A structure, sep-
arate from a main building such as a church,
once used as a temporary shelter for horse-drawn
wagons before the use of automobiles; usually
had at least one open side so that the wagons
could be driven directly into the shed without
having to open doors.

■wagon stage A stage mounted on wheels or
rollers, usually powered; moves horizontally
for the quick change of an entire theatrical
setting.

wagon vault A semicylindrical vault; a barrel

vault,
wagtail See parting slip.

wainscot A decorative or protective facing,
such as wood paneling, that is applied to the
lower portion of an interior partition or wall.
Also see falling wainscot.

wainscot cap The molding which finishes the
upper edge of a wainscot.

wainscot oak Quartersawn oak, often spe-
cially selected, used in wainscoting.

■waist The narrowest thickness of the slab in con-
crete stairs.

■waiver of lien An instrument by which a per-
son or organization who has or may have a right of
mechanic's lien against the property of another
relinquishes such right. Also see mechanic's lien
and release of lien.

wale, waler, whaler A horizontal timber or
beam used to brace or support an upright mem-
ber, as sheeting, formwork for concrete, etc. (See
illustration p. 1052.)

waling See wale.

■walk A pedestrian path or passageway.

1051

walk-in

WALES

wale

walk-in To imbed panels of insulation in hot
bitumen or adhesive by walking on them imme-
diately after application.

walk-in box A refrigerated cooler or freezer
large enough for one or more persons to enter.

walking beam pivot A type of retractable
center pivot.

walking line, line of travel The usual path
taken in climbing stairs, approximately 18 in.
(46 cm) from the center line of the handrail.

walk-out basement Same as American base-
ment.

walk»up l.An apartment building or commer-
cial building without an elevator. 2. An apartment
or office above the entry floor in such a building.

walk'Walk A passageway along the wall of a
castle; usually behind the parapet of the curtain
wall, 2.

walkway l.A passage or lane designated for
pedestrian traffic, esp. one connecting various
parts of an industrial plant or along roofing. 2. A
garden footpath.

■wall l.A structure which serves to enclose or
subdivide a building, usually presenting a contin-
uous surface except where penetrated by doors,
windows, and the like. 2. A rampart. 3. A retain-
ing wall. For specific types, see battered wall, bear-
ing wall, blank wall, blind wall, boarded wall,
board wall, breakaway wall, cavity wall, common
wall, composite wall, counterwall, curtain wall,
dead wall, dry wall, dry-stacked surface-bonded

wall, fire wall, gable-end wall, hollow wall, load-
bearing wall, masonry-bonded hollow wall, mud
wall, non-load-bearing wall, partition, party wall,
retaining wall, serpentine wall, spandrel wall,
springing wall, street wall, structural wall, sus-
taining wall, veneered wall.

■wall anchor A wrought-iron clamp, often dec-
orative, on the exterior side of a brick building
wall that is connected to the opposite wall by a
tie rod to prevent the walls from spreading apart;
same as anchor, 10.

wall arcade A blind arcade used as an orna-
mental dressing to a wall.

wall base See base, 2.

■wall beam A metal member which acts as a

beam anchor.
wall bearer See bearer.

wall-bearing partition A load-bearing parti-
tion.

wall bed, recess bed A bed which folds and
stands vertically when not in use, usually swung
into a closet or recess; esp. used in apartment
houses.

wallboard A rigid sheet composed primarily of
wood-pulp, gypsum, or other materials; may be
fastened to the frame of a building to provide an
interior surface finish; the long edges of the
board usually are tapered to provide easy treat-
ment of the joints when board is erected. Also
see dry wall.

wall box, beam box, wall frame 1 . A frame
or box which is set into a brick, masonry, or
stone wall to receive a timber beam or joist. 2. In
electrical wiring, a metal box which is set in a
wall for switches, receptacles, etc.

wall bracket l.A bracket which is fixed to a
wall and used to support a structural member.
2. A bracket used to support a scaffold. 3. A
bracket used to support piping, an electrical com-
ponent, or a lighting fixture.

wall chase See chase, 1.

■wall cladding A nonstructural material used as
the exterior covering for the walls of a building;
see cladding.

■wall clamp A brace or tie to hold together two
walls, or the two parts of a double wall.

wall cleanout A cleanout, 1 mounted on a
wall; used where a drainage line is concealed

1052

wall furring

wall bracket, 3

T\ — T

Access cover

wall cleanout

behind a partition; a removable panel provides

access to the cleanout.
■wall clip A bracket that is used to anchor a wall.
■wall column A column which is embedded, or

partially embedded, in a wall.
wall coping See coping.

■wall covering Any material or assembly which

is used as a wall facing and is not an integral part

of the wall.
■wall crane A crane having a horizontal arm

(with or without a trolley); supported from a

sidewall or line of columns of a building; has a

maximum swing of a half circle.
■wall dormer A dormer whose face is integral

with the face of the wall below, breaking the line

at the cornice of a building.

through-the-c

: wall dormer

wall flange Same as wall clip.

■wall form A concrete form which is erected to
provide the necessary shape, support, and finish
for a concrete wall.

wall frame See wall box, 1.

wall furnace A self-contained, vented fur-
nace, complete with air grilles, which is perma-
nently attached to a wall; furnishes heated air
directly to the surrounding space, either by grav-
ity or by a mechanical blower.

■wall furring Strips of wood or metal, masonry
tiles, etc., applied to the rough surface of a wall
so as to provide a flat plane upon which a surface
material, or assembly, such as lath and plaster,

1053

wall gable

wood paneling, wainscoting, etc., may be in-
stalled. Also see furring.

■wall gable A portion of a wall that projects
above the roof line in the form of a gable.

■wall garden A garden of plants set in the joints
of a stone wall, where soil pockets have previ-
ously been arranged.

■wall grille A perforated plate, casting, molding,
or framed bars or rods to cover a wall opening,
radiator enclosure, etc., restricting vision but per-
mitting the flow of air.

■wall guard A protective, resilient strip which is
applied to the surface of a wall (esp. along a cor-
ridor) to prevent its being damaged by carts,
wagons, and the like.

wall handrail A rail, 1 similar to a handrail,
but attached to a wall adjacent to a stair, paral-
leling the pitch of the flight.

wall hanger A stirrup or bracket built into a
masonry wall to carry the end of a horizontal
member.

■wall height The vertical distance to the top of a
wall, measured from the foundation wall, or from
a girder or other immediate support of such wall.

■wall hook 1. A special large nail or hook used
as a beam anchor or for holding a wall plate fixed
in position. 2. Same as wall iron.

wall-hung water closet A water closet
mounted on a wall, so that no part of it touches
the floor.

wall-hung water closet

walling 1. Walls collectively. 2. Materials for

constructing walls.
■wall iron A hook or bracket fixed to a masonry

wall to hold downspouts, lightning rods, etc.; a

wall hook, 2.

■wall joint The mortar joint between the
stretchers in a brick wall; runs at right angles to
a head joint.

■wall line A line along the exterior face of a wall.

■wall liner A sheet of fabric which is applied to a
wall to prevent cracks, small gaps, or the like from
showing through a covering such as wallpaper.

wall opening According to OSHA: an open-
ing at least 30 in. (76.2 cm) high and 18 in.
(45.8 cm) wide, in any wall or partition, through
which persons may fall, such as a chute opening.

■wall outlet An electrical receptacle, whose face
is flush with a wall, into which a plug is inserted.

wall panel A panel wall.

■wallpaper Paper, or paper-like material, usually
decorated in colors, which is pasted or otherwise
affixed to walls or ceilings of rooms.

wall piece See wall plate, 2.

■wall plate A horizontal member (such as a tim-
ber) across a timber-framed, masonry, or con-
crete wall to carry and distribute the load
imposed by members that support the roof.

CEILING BEAM

TOP WALL
PLATES

wall plate, 1

wall plug 1. Same as wall outlet. 2. A plug, 1.

wall pocket Same as wall box.

■wall post 1. A post which is next to a wall, in a
partition. 2. A post, fixed to a wall, against which
a fence terminates, or from which a gate may be
hung. 3. A post that supports a wall plate.

wall rail Same as wall handrail.

■wall rib In medieval vaulting, a longitudinal rib
against an exterior wall of a vaulting compart-
ment.

■wall shaft A colonette supported on a corbel or
bracket which appears to support a rib of vaulting.

wall siding See siding.

1054

wane

■wall sign 1. A sign mounted on, or fastened to,
a wall. 2. In some codes in the US, a sign
attached to the exterior wall of a building and
projecting not more than 15 in. therefrom.

wall socket A wall outlet.

■wall spacer A metal tie for holding a concrete
form in position until the poured concrete has set.

wall stay Same as anchor, 10.

wall string, wall stringer A stair string set
against a wall.

■wall tower A tower forming an essential part of
a defensive wall, especially one having a series of
towers to enhance its fortification.

wall string S

■wall tie In masonry, a type of anchor (usually
a metal strip) used to secure facing to a backup
wall or to connect the two withes of a cavity
wall; mortared into joints during setting. Also
see butterfly wall tie, cavity wall tie, veneer
wall tie.

wall tower

wall tracery Tracery that is false in the sense
that there is no associated openwork; instead,
the tracery is shown in relief on a solid wall.

■wall vent A ventilation device for a wall cavity,
crawl space, or attic.

wall-washing Lighting a wall by luminaires
located close to the plane of the wall.

wall-wash luminaire Any luminaire located
adjacent to a vertical surface on which its light is
principally directed.

■walnut A tough, dark brown-to-black wood
having high strength; does not split easily; has a
fine-to-coarse open grain; takes a high polish.

■wane A rounded edge or bark along an edge or
at a corner of a piece of lumber; usually caused
by sawing too near the surface of the log.

wall ties

wall tile A glazed tile, 1 used as a facing on a wall.

1055

ward

■ward 1 . A metal obstruction in a lock; intended
to prevent entrance or rotation of a key that does
not fit the lock. 2. The outer defenses of a castle.
Also see bailey. 3. A division in a hospital.

wardrobe, garderobe A room for the storage
of garments.

■warehouse A building designed for the storage
of various goods.

warehouse set The partial hydration of
cement stored for periods of time and exposed to
atmospheric moisture.

ware pipe Same as vitrified-clay pipe.

warm-air furnace A self-contained unit for
heating air which is circulated through it; the air
either is conveyed through ducts or is discharged
directly into the space being heated.

warm-air heating system A warm-air heat-
ing plant consisting of a fuel-burning furnace,
enclosed in a casing, from which the heated air
is distributed to various rooms of the building
through ducts.

warming-house Same as calefactory.

warm-setting adhesive An intermediate-
temperature-setting adhesive.

warning pipe An overlow pipe whose outlet is
conspicuous, so that discharge from it can be
observed readily.

warp 1. See carpet warp. 2. Distortion in shape
of a parallel plane surface; in lumber, usually
results from a change in moisture content.

■warped Said of thin-bedded rock, such as flag-
ging, having a natural curved or a rippled finish
similar to warped wood.

■warping The deviation of a surface from its
original or intended shape, as a concrete slab or
wall surface; esp. caused by moisture and tem-
perature differentials.

■warping joint A joint permitting warping of
pavement slabs when moisture and/or tempera-
ture differentials occur in the pavement.

■warp 'wire In wire cloth, a wire running parallel
to the length of the cloth.

warranty See guarantee.

■warranty deed A written instrument convey-
ing real property, in which the grantor makes
legally binding representations concerning the
quality of his title and its freedom from encum-
brances.

Warren truss, Warren girder A form of truss
having parallel upper and lower chords, with
connecting members which are inclined, form-
ing a series of approximately equilateral triangles.

■wash l.The sloping upper surface of a building
member, as a coping or sill, to carry away water;
said of any other member serving such a function.
See also drip cap. 2. A manner of applying water
color in a rendering. Also see wall-washing.

■washable Capable of being washed repeatedly
without significant erosion and without change
in appearance or functional characteristics.

washable distemper A distemper which con-
tains an emulsified oil, giving washable charac-
teristics to a distemper coating.

washbasin Same as lavatory, 1.

washboard Same as baseboard.

wash boring The drilling of test hole in the
ground to obtain soil samples that are brought
up along with a mixture of water.

■wash coat A very thin, semitransparent coat of
paint; applied as a preliminary coating on a sur-
face; acts as a sealer or guide coat.

washed finish See rustic finish.

■washer A flat ring, usually thin, of metal, rub-
ber, or other material, depending on its use; used
to prevent leakage, to provide insulation; used as
the bearing surface under the head of a fastener,
such as a bolt, to assure tightness, relieve fric-
tion, improve stress distribution, or span large
clearance holes.

FLAT WASHER

SHAKEPROOF
WASHER

■wash fountain A large lavatory-type vessel
which supplies tempered water for group wash-
ing of hands and faces.

wash light Same as wall-wash luminaire.

■wash primer A primer containing polyvinyl
butyral, zinc chromate, alcohol, and phosphoric
acid; applied in a thin film to bare steel, causes
etching of the metal, thereby promoting adhe-
sion of the subsequent coat.

1056

water-base paint

washroom A room providing facilities for
washing; a lavatory or toilet room.

wash water, flush water Water carried on a
truck mixer in a special tank for flushing the
interior of the concrete mixer after discharge of
the concrete.

■waste l.The discharge from any fixture, appli-
ance, area, or appurtenance which contains no
fecal matter. 2. See sanitary waste. 3. Waste mate-
rial such as garbage, refuse, rubbish, and trash.

waste branch Same as waste pipe.

waste compactor See compactor, 2.

waste-disposal unit An electric-motor-driven
device for grinding waste food and disposing of it
through the plumbing drainage pipes; may be
installed without a grease trap in a residence.

Motor

waste-disposal unit

waste-food grinder Same as waste-disposal
unit.

■waste fuel A fuel which is a waste by-product
of some industrial process.

waste-heat recovery The use of waste heat in
a building to preheat cold water before it is fed
into a hot-water heater.

waste management 1. In the public sector, a
systems approach to the efficient control of the
disposal of waste in a community or region;
requires the establishment of a policy regarding
environmental standards, the collection and
treatment of wastes, the monitoring of air, soil,

and water quality, and the enforcement of estab-
lished regulations. 2. In for-profit organizations,
the carrying out of similar functions, with the
exception of enforcement.

waste material See garbage, refuse, rubbish,
and trash.

■waste pipe A drainpipe which receives the
waterborne discharge from plumbing fixtures
other than those fixtures receiving fecal matter;
also see indirect waste pipe.

■waste plug A tapered device used to prevent
the flow of water through the drain of a wash-
basin or the like.

waster A second or cull.

■waste receptacle A container for holding or
facilitating the removal of refuse.

■waste stack A vertical pipe which conveys liq-
uid wastes which are free of fecal matter.

waste vent Same as stack vent, 1.

waste water See waste.

waste well Same as leaching cesspool.

■wasting In stonecutting, splitting off the surplus
stone with a wedge-shaped chisel (called a point),
or with a pick, so that the faces of the stone are
reduced to nearly plane surfaces; dabbing.

wat, vat Buddhist monastery in Cambodia.

watching loft l.Same as excubitorium, 1. 2. A
lookout in a tower, steeple, or other high building.

watchman's system An approved installa-
tion of equipment used to record the rounds of a
watchman.

watch turret Same as bartizan.

water absorption Of a test specimen, the
increase in weight after immersion in water for a
specified time, expressed as a percentage of its dry
weight; usually the test conditions are specified.

■water analysis A chemical analysis of the dis-
solved materials in water, including a determina-
tion of the amount of suspended solids and the
pH value.

■water back A system of pipes or a reservoir of
water at the back of a fireplace, or the like, to
utilize its heat in providing a supply of hot water.

water bar, weather bar A wood or metal
strip which is fixed to the sill of an external door
or a window to resist the penetration of water.

water-base paint A paint capable of being
thinned or diluted with water; for example, casein
paint, latex paint, vinyl paint.

1057

water blasting

■water blasting The cutting or abrading of an
exterior surface by a stream of water ejected from
a nozzle at high velocity.

waterboard An obsolete term for watertable, 1 .

waterborne preservative A water-soluble
chemical used to treat wood for protection
against decay and insects.

water cement Same as hydraulic cement.

water-cement ratio The ratio of the amount
of water, exclusive only of that absorbed by the
aggregates, to the amount of cement in a con-
crete or mortar mixture.

water channel, condensation channel A
trough-like depression in the top of the interior
sill of a glazed opening to collect and drain away
condensed moisture which forms on the interior
face of the glass.

water check Same as upstand.

water-checked casement A casement hav-
ing grooves cut under the sill and meeting stile
to prevent capillary movement of water.

water closet, W.C. 1. A plumbing fixture used
to receive human excrement and to discharge it
through a waste pipe, using water as a conveying
medium. 2. A room containing a water closet, 1.

DISCHARGE

REFILL TUBE

INTAKE
VALVE

SUPPLY
PIPE

OVERFLOW

FLOAT

WATER
LEVEL

■TANK
BALL

FLUSH
VALVE

water closet flush tank

water content Same as moisture content.

water cooler Same as drinking-water cooler.

water-cooling tower A structure, usually
on the roof of a building, over which water is
circulated, so as to cool it evaporatively by
contact with the air.

water course See damp course.

INTAKE

water-cooling tower

■water crack In plastering, a fine crack in a coat
applied before the previous coat has dried, or in
a coat having excessive water in the plaster.

water curtain A deluge sprinkler system above
a theater proscenium.

water deactivation See deactivation.

water distributing pipe A pipe, in a building,
which conveys water from the water service pipe
to plumbing fixtures or other water outlets.

■water filter A device for the removal of, or
reduction of, suspended solid contaminents in
water by passing the water through a porous
medium.

water filtration See filtration.

waterflow-alarm In a fire sprinkler system, an
alarm which is actuated when the flow through
the sprinkler system is in excess of a predeter-
mined maximum value.

water fountain l.See architectural fountain.
2. See drinking fountain. 3. See wash fountain.

water gain See bleeding, 4.

■water garden A garden making use of pools in
which aquatic and other water-loving plants are
grown.

water gauge A manometer filled with water.

water-gel explosive One of a wide variety of
materials used for blasting; contains substantial
proportions of water and a high proportion of
ammonium nitrate, some of which is in solution
in the water.

1058

waterproofing

water harvesting Any combination of tech-
niques that result in storm water being captured
on-site for later use.

water hammer l.In water lines, a loud
thumping noise that results from a sudden stop-
page of the flow. 2. In steam lines, water of con-
densation that is picked up and carried through
the steam main at high velocity; when direction
of the flow changes, the water particles hit the
pipe walls, emitting a banging noise.

water-hammer arrester A device installed
in a piping system to absorb hydraulic shock
waves and eliminate water hammer, 1 .

water-hardened Said of a metal that has been
quenched in water after being heated to a criti-
cal temperature.

■water heater A device for heating water for
domestic use, usually supplied at a temperature
in the range between 120°F and 140°F (approx.
50°C and 60°C).

■water joint l.A joint in a stone pavement
where the stones are intentionally placed
slightly higher than elsewhere; the raised surface
is intended to prevent the settling of water in
the joints. 2. A saddle joint, 1.

■water leaf 1. In early Roman and Greek orna-
mentation, a type of lotus leaf or an ivy motif.
2. Similar to water leaf, 1 but divided symmetri-
cally by a prominent rib; also called a Lesbian
leaf. 3. Late 12th cent, capital with a large leaf at
each angle, broad, smooth, curving up toward
the abacus corner and then curling inward.

close limits; use of the control makes it unneces-
sary to add large quantities of replacement water
at any one time.

■water lime Hydraulic lime or hydraulic cement;
will set under water.

waterline Inside a cistern, the highest water
level to which the ball valve should be adjusted
to shut off.

■water main A main supply pipe in a system for
conveying water for public or community use,
controlled by a public authority.

water meter A mechanical device used to
measure the volume of water passing through a
pipe or outlet.

■water mill A mill, 3 that is powered, by running
water, such as a stream; also see tidemill.

water motor alarm In a fire sprinkler system,
a hydraulically actuated device that provides a
local audible alarm when water flows through
the wet alarm valve.

■water outlet 1 . An opening for the discharge of
water that supplies a plumbing fixture, boiler, or
heating system, or any device or piece of equip-
ment which is not part of a plumbing system but
requires water to operate. 2. An opening through
which water is discharged into the atmosphere.

■waterproof In the building trades, descriptive
of any material or construction which is imper-
vious to water.

■waterproofing A material, usually a membrane
or applied compound, used to make a surface
impervious to water.

water leaf, 1: left, simple; right, enriched

water-leaf capital Same as water leaf, 3 .

■water level A simple device for establishing
two points at the same elevation; consists of a
water-filled flexible hose (from which air has
been excluded) with a piece of glass tubing at
each end; the water level is observed through
the glass tubing.

water-level control A control used to main-
tain the water level in a boiler to reasonably

MASONRY

UNIT WALL

GRAVEL

waterproofing applied to masonry wall units

1059

waterproofing compound

waterproofing compound Any applied ma-
terial which imparts the quality of waterproofing

to a surface.

■waterproof paper A water-impervious paper;
usually a synthetic resin has been added to the
pulp or mixed with the sizing.

waterproof portland cement A portland
cement interground with a water-repellent mate-
rial such a stearate (e.g., sodium or aluminum);
reduces capillary water transmission under little
or no pressure but does not completely stop
water-vapor transmission.

■water pump A device for raising fresh water
from a lower elevation where it is available, to a
higher elevation where it can be used; where
electricity is not available, pumps are often pow-
ered by windmills.

water putty A type of wood filler; a powder
which becomes putty-like when mixed with
water; used to fill small holes and cracks in
wood.

■water ramp A series of pools, arranged so that
water flows from one to another.

water-reducing admixture l.An admix-
ture which either (a) increases the slump of
freshly mixed concrete or mortar without
increasing the water content or (b) maintains
the slump with a reduced amount of water due to
factors other than air entrainment. 2. In con-
crete, an admixture which can produce a large
reduction in water or flowability without an
undue set retardation or entrainment of air.

water-reducing agent A material which
either increases workability of freshly mixed
mortar or concrete without increasing its water
content or maintains workability with a reduced
amount of water.

water repellent 1 . Said of a surface that is resis-
tant to, but not impervious to, water penetration.
2. A material used to treat a surface to increase
its resistance to the penetration of water.

water-repellent cement A hydraulic cement
having a water-repellent agent added during the
process of manufacture.

water-repellent preservative A water repel-
lent, 2 that provides moderate protection against
the deterioration of wood.

■water resistant Said of any material capable of
withstanding limited exposure to water.

water retentivity That property of a mortar
which prevents the rapid loss of water by absorp-
tion to masonry units; prevents bleeding or water
gain when mortar is in contact with relatively
impervious units.

water riser pipe See riser, 4.

■water seal The barrier to the passage of air
through a trap, 1 in a drain, which is provided by
water in the trap; a seal, 3.

■water seasoning The seasoning of lumber by
soaking it in water for a period of time prior to
air drying.

water-service pipe That part of a building
main installed by, or under the jurisdiction of, a
water department or company.

■watershed 1 . A dividing line between drainage
areas. 2. A wash, 1. 3. A water table, 1. 4. An
area from which a community or region receives
its supply of water.

watershed dormer Same as shed dormer.

■water softener An apparatus which chemi-
cally removes the calcium and magnesium salts
from a water supply, usually by ion exchange.
Also see zeolite.

water spotting, white spots White marks
which are left on a paint film when droplets
of water evaporate, or as a result of sealing in
moisture.

waterspout A duct, spout, or the like, through
which rainwater is discharged from a roof or
gutter; for examples, see gargoyle and canale.

water-spray fixed system A fire sprinkler
system that sprays water in a predetermined pat-
tern, and with a predetermined water-particle
size, velocity, and density; usually discharged
from especially designed nozzles.

■water stain 1 . Discoloration in converted tim-
ber caused by water. 2. A water-soluble dye used
as a stain for wood that is to be finished.

water standpipe system See standpipe sys-
tem.

■water stop A diaphragm used across a joint as a
sealant, usually to prevent the passage of water.

water-struck brick See soft-mud brick.

water supply fixture unit (WSFU) A factor
so chosen that the load-producing effects of dif-
ferent kinds of plumbing fixtures and their condi-
tions of service can be expressed as multiples of
that factor.

1060

wattle-and-daub

water supply stub A vertical pipe less than
one story in height supplying one or more fix-
tures.

water-supply system Of a building, the
water-service pipe, the water-distributing pipes,
and the necessary connecting pipes, fittings,
control valves, and all appurtenances in or adja-
cent to the building.

■water table 1. A horizontal exterior ledge on a
wall, pier, buttress, etc.; often sloped and pro-
vided with a drip molding to prevent water from
running down the face of the lower portion; also
called an offset, 1. Also see base course, drip
cap. 2. Same as groundwater level.

MOLDED DRIP

CAP ~~

water table, 1

■water tank An enclosed storage container, usu-
ally pumped to an elevated location, to increase
the water pressure in a water piping system.

water tap A water outlet valve; a faucet.

■water test 1 . A test to determine whether there
are leaks in a system of piping. Also see test plug
and test pressure. 2. A test of a drainage or vent
system to determine if it leaks; should not be
used in locations where the temperature during
the test may fall below the freezing point of
water. Also see air test.

■water theater A terraced structure in which
water flows from higher terraces to lower ones.

■watertight 1 . Said of an enclosure or barrier that
does not permit the passage of moisture. 2. Said of
a surface that is impermeable to water except
when exposed to a hydrostatic pressure sufficient
to produce structural discontinuity by rupture.

■water tower A tower into which water is
pumped to raise its level high enough above the
level of a water distribution system so that the
system will be supplied with adequate water
pressure.

■water valve A device in a water distribution
system to start or stop, regulate, or prevent the
reversal of flow of water in a system.

water vapor barrier See vapor barrier.

water vapor diffusion The process by which
water vapor spreads or moves through permeable
materials caused by differences in water vapor
pressure.

water vapor permeability That property of a
material which permits the passage of water
vapor through it; the time rate of water vapor
transmission through a unit area of flat material
of unit thickness induced by a unit vapor pressure
difference between two specific surfaces, under
specified temperature and humidity conditions.

water vapor retarder See vapor barrier.

water vapor transmission (WVT) The
rate of water vapor flow, under steady specified
conditions, through a unit area of material
between the two parallel surfaces (and normal to
these surfaces).

water well See well, 4.

■waterworks A complete system of pipelines,
conduits, and so forth for distributing water from
one or more reservoirs, purifying the water, and
then pumping it through a distribution system
for use by a community.

■watt A unit of power; the power required to do
work at the rate of 1 joule per second, which is
equal to the power dissipated in an electric cir-
cuit in which a potential difference of 1 volt
causes a current of 1 ampere to flow.

watt- hour A unit of work equal to 3 ,600 joules;
equivalent to the power of 1 watt operating for a
period of 1 hour.

watt-hour meter An electricity meter which
measures and registers the active power in an
electric circuit with respect to time.

■wattle A framework of interwoven rods, poles,
or branches.

wattle-and-daub A primitive form of wall
construction consisting of upright wood poles
with branches interwoven between them (wattle)
that are then covered with plaster mixed with

1061

wave front

wattle

wattle-and-daub

clay and straw (daub); often used to fill the space
between structural timbers of timber-framed
buildings in order to provide increased thermal
insulation; also see jacal, 2.

■wave front Of a sound wave, a continuous,
imaginary surface which is the locus of points
having the same phase at a given instant.

■wavelength For light waves or sound waves,
the distance between two successive points of a
periodic wave in the direction of propagation, in
which the oscillation has the same phase; the
distance the wave travels in one period. For light
waves three common units of wavelength are:
micrometer, nanometer, and angstrom.

wave molding, oundy molding, swelled
chamfer, undulating molding, undy
molding A molding decorated with a series
of stylized representations of breaking waves.

wave scroll Same as Vitruvian scroll.

■wavy grain A curly figure in wood grain, simi-
lar to fiddleback, but with more uniform ripples
and waves.

■wax A thermoplastic solid material obtained
from vegetable, mineral, and animal matter; sol-
uble in organic solvents; used in paste or liquid
form as a protective coating or polish on wood
and metal surfaces and as an additive in paints.

■waxing In a finished piece of marble intended
for interior use, the filling of cavities with mate-
rials patterned and colored to match.

■way A street, alley, or other thoroughfare or
easement permanently established for the pas-
sage of persons or vehicles.

WB Abbr. for "welded base."

WBT Abbr. for wet-bulb temperature.

W.C. Abbr. for water closet.

WCV Symbol for "butterfly (wafer) check valve."

wd Abbr. for wood.

Wdr In the lumber industry, abbr. for "wider."

■weak axis The minor principal axis of a cross
section.

weakened-plane joint Same as groove joint.

wearing surface, wearing course l.The
top layer of surfacing which carries vehicular
traffic. 2. Same as topping.

■weather That portion of a wood shingle that is
exposed to the elements.

■weather back The application of weather-
proofing to the back (inner side) of a wall.

weather bar See water bar.

weather barrier On the outer surface of ther-
mal insulation, any material which protects the
insulation from weather damage, including solar
radiation and atmospheric contamination.

weatherboard One of a number of horizontal
boards commonly used as an exterior covering
on timber-framed buildings to provide weather
protection; for example, used as exterior sheath-
ing to protect the infilling between the structural
timbers. The upper edges of weatherboards are
commonly tapered to a thinner edge than the lower
edge so they can be overlapped by the weather-
boards directly above them, or they have a
rabbeted upper edge that fits under the over-
lapping board above, to shed water. Also see
clapboards, which served the same purpose but
were usually not as thick as weatherboards; also
see siding.

weatherboarding l.A type of wood siding
commonly used in the early US as an exterior
covering on a building of frame construction;
consists of boards, each of which has parallel
faces and a rabbeted upper edge which fits under
an overlapping board above. 2. Same as clap-
board or siding.

weather check Same as throat, 2.

weathercock A weathervane in the shape of a

rooster.
weather door See storm door.

■weathered 1. Descriptive of a material or sur-
face which has been exposed to the elements for
a long period of time. 2. Having an upper sur-
face which is splayed so as to throw off water.

weathered joint See weather-struck joint.

1062

weaving

weatherboarding, 1

weathered pointing Same as weather-struck

joint.
weathered steel A high-strength steel whose

own corrosion protects it from further corrosion.

■weathered stone Stone that has been exposed
to the elements over a long period of time, often
resulting in changes in color or the development
of a patina.

weather fillet See cement fillet.

weathering 1. Changes in color, texture,
strength, chemical composition, or other prop-
erties of a natural or artificial material due to the
action of the weather. 2. See sill offset. 3. The
cover applied to a part of a structure to enable it
to shed rainwater.

weather joint See weather-struck joint.

weather molding A molding shaped and
located to discharge rainwater; same as dripmold.

weatherometer A device in which specimen
materials can be subjected to artificial and accel-
erated weathering tests, the effects of sun, rain,
and temperature changes; the simulated condi-
tions are usually obtained by the use of electric
arcs, water spray, and heating elements.

■weatherproof So constructed or protected
that exposure to the weather will not interfere
with successful operation or function.

weather resistance The ability of a material,
paint film, or the like to withstand effects of
wind, rain, sun, etc., and retain its appearance
and integrity.

weatherseal channel Of a door, a top-closing
channel which is set in mastic with its flanges
downward.

weather shingling Shingles that are hung
vertically on the face of a wall, usually attached
by nailing; provides protection against the pene-
tration of moisture through the wall.

weather slating, weather tiling Slate or tile
shingles that are hung on the face of a wall to
prevent the penetration of rainwater.

■weather strip A strip of wood, metal, neoprene,
or other material applied to an exterior door or
window so as to cover or seal the joint made by it
with the sill, casings, or threshold, in order to
exclude rain, snow, cold air, etc.

weather-struck joint, weathered joint A
horizontal masonry joint in which the mortar is
sloped outward from the upper edge of the lower
brick, so as to shed water readily; formed by
pressing the mortar inward at the upper edge of
the joint.

weather-struck joint

weathertight Sealed against the intrusion of
rain, snow, cold air, etc.

weather tiling, tile hanging Tile which is
hung vertically on the face of a wall; usually
attached by nailing; provides protection against
moisture.

weather vane A metal plate, often decorated,
or in the shape of a figure or object, which
rotates freely on a vertical spindle to indicate
wind direction; usually located atop a spire or
other elevated position on a building.

weave bead A weld bead which is made with
oscillations along the bead which are transverse
to the length of the bead.

■weaving In shingled roofing, where two adjoin-
ing surfaces meet, the alternate lapping of shin-
gles on opposite faces.

1063

weaving house

weaving house Same as spinning house.

■web 1 . The portion of a truss or girder between
the chords or flanges, whose principal function
is to resist shear on the span. 2. A core divider in
a hollow masonry unit.

web, 1

■web bar Steel reinforcement which is placed in
a concrete member to resist shear and diagonal
tension.

■web clamp A type of clamp used to hold car-
pentry work during gluing; consists of a tape of
nylon, or the like, with a metal fastener that is
tightened with a wrench or screwdriver.

web crippling The local failure of a web
plate, for example, as the result of a concen-
trated load.

■web member In a truss, any member which
joins the top and bottom chords.

WEB
MEMBER

WEB MEMBERS

web i

■web plate A steel plate which forms the web, 1
of a beam, girder, or truss.

web reinforcement 1. Steel bars, rods, etc.,
placed in a reinforced concrete member to resist
shear and diagonal tension. 2. Additional metal
plates connected to the web, 1 of a metal beam
or girder to increase the strength of the web, 1.

■web splice A splice joining two web plates.

web stiffener An angle iron which is con-
nected to the web, 1 of a beam to distribute a
load or to prevent buckling.

■wedge 1. A piece of wood, metal, or other hard
material, thick at one end and tapering to a thin
edge at the other. 2. See lead wedge.

■wedge anchor In prestressed concrete, a
device for providing the means of anchoring a
tendon by wedging.

wedge coping Same as featheredge coping.

■weepers Statues of mourners sometimes incor-
porated into tombs.

■weep hole 1. A small opening in a wall or win-
dow member, through which accumulated con-
densation or water may drain to the building
exterior, as from the base of a cavity wall, a wall
flashing, or a skylight. 2. A hole near the bottom
of a retaining wall, backfilled with gravel or
other free -draining material, to permit water to
drain to the outside of the wall, so as to prevent
the buildup of pressure behind the wall.

weep hole tile A tile, with a hole through it,
used in the first course, 2 above a gutter in the
roof. Water that passes through the hole drops
directly into the gutter. See weep hole.

weeping cross A type of preaching cross espe-
cially used for public penance.

weft See carpet weft.

weight batching Measuring the constituent
materials for mortar or concrete by weight,
rather than by volume.

weight box In a window frame, the channel in
which the sash weights move up and down.

weight pocket, weight space A weight box.

weighting network An electrical circuit that
alters the sensitivity-<us-frequency characteristic
of a sound level meter so as to improve the cor-
relation between meter readings and the subjec-
tive judgment of noise by individuals. See the
A-scale, which is the most widely used weighting

1064

weld metal

network for measuring noise levels of equip-
ment, in buildings, and in the community.

■weld To unite metals by heating them to suit-
able temperatures, with or without the applica-
tion of pressure, and with or without the use of
filler metal.

■weld axis A line through the length of a weld
that is perpendicular in its cross section.

■weld bead A weld deposit resulting from a sin-
gle longitudinal progression of a welding opera-
tion along a joint.

■weld decay Localized corrosion at or adjacent
to a weld.

welded butt splice A reinforcing bar splice
made by welding the butted ends.

welded cover plate A cover plate welded to a
beam or girder.

■welded joint A gastight joint obtained by unit-
ing metal parts, such as iron and steel that
require welding, in the plastic or molten state.

BUTT JOINT

(SSSSSS* 23

EDGE JOINT

CORNER JOINT

LAP JOINT

TEE JOINT

welded joints

welded reinforcement Reinforcement which

is joined by welding.
■welded system A piping system for conveying

fluids, in which all joints are welded, usually to

make the system leakproof.

■welded truss Any truss having its main mem-
bers joined by welding.

■welded tube Tube made from a metal plate,
sheet, or strip, with welded longitudinal or heli-
cal joint.

welded-wire fabric, welded wire mesh A
series of longitudinal and transverse wires
arranged at right angles to each other and welded
together at all points of intersection; used as rein-
forcement in reinforced concrete.

fr* '

U . — . — .

welded-wire fabric

welded-wire fabric reinforcement The use

of welded-wire fabric as reinforcement in concrete.
welded wire lath Same as wire lath.

■weld gauge An instrument for checking the

shape and size of welds.

■welding cables A pair of electric cables supply-
ing power from a welding machine to the work
being done; one lead connects the machine with
the electrode holder, the other lead connects the
machine to the work.

welding nozzle A short length of pipe which
is welded to a vessel at one end and is chamfered
at the other end for butt welding.

welding rod Filler metal, in wire or rod form,
used in gas welding and brazing processes and in
those arc-welding processes wherein the elec-
trode does not furnish the filler.

■welding screw A screw provided with lugs or
weld projections on the top or underside of the
head to facilitate attachment to a metal part by
resistance welding.

weldment Any assembly whose component
parts are joined by welding.

■weld metal The part of a weld that has been
melted during welding.

106S

weld nut

■weld nut A solid nut provided with lugs, annu-
lar rings, or embossments to facilitate its attach-
ment to a metal part by resistance welding.

well-burnt Same as hard-burnt

■well, wellhole 1. The clear vertical space about
which a stair turns; a stairwell. 2. The open verti-
cal space between walls in which a stair or eleva-
tor is constructed. 3. Any enclosed space of small
area but of considerable height, as an air shaft,
well, 4. See bored well, dug well, etc.

well, 1: W

■well curb A protective structure around the top
rim of a well, 4 to prevent objects from falling
into it; also provides a convenient mounting sur-
face for a mechanism for raising a water bucket.

well curbing Same as pit boards.

well-graded aggregate Aggregate having a
particle-size distribution which will produce
maximum density, i.e., minimum void space.

■wellhole The open vertical space between
walls in which a stair is constructed; see well, 1.

well house, wellhead A shelter over a water
well, 4.

■well point A hollow rod with a perforated
intake at its lower end, which is pointed; driven
into the ground and connected to a pump, to
remove water at an excavation site.

well-point system A number of well points con-
nected to a header, which is attached to a pump, to
lower the water table at an excavation site.

well stair A stairwell in a well, 1 .

Welsh arch Same as flat arch.

well points

HEADER PIPE

well-point system

Welsh groin A groin formed by an underpitch

vault.
Welsh vault See underpitch vault.

■welt 1 . In sheet-metal roofing, a seam which
joins two sheets; formed by folding over the
edges of the sheets, engaging the folded portions
and then dressing them down flat. 2. A strip of
wood fastened over a flush seam or joint, or an
angle, to strengthen it.

■welted drip A drip formed by roofing felt at the
eaves or the rake edge of a roof; a strip is folded
back to return on the roof, forming the drip.

welting strip In sheet-metal roofing, a strip
having one edge fixed to the roof and the other
edge bent to hold the lower edge of a vertical
sheet. Also see stripping, 3.

1066

wet stable consistency

■west end The end of a church that is opposite
the sanctuary; usually where the main doors are
located; so called because medieval churches
almost invariably had their sanctuaries at the
east end.

■west front The end wall of a medieval church,
usually opposite the sanctuary, and usually
where the main doors are located.

western frame See platform frame.

western framing A system of framing a build-
ing of wood construction in which all studs are
only one story in height; the floor joists for each
story rest on the top plates, 2 of the story below,
except for the first story, which rests on the
groundsill. The bearing walls and partitions rest
on the subfloor (i.e., on the rough floor that
serves as a base for the finish floor). Same as plat-
form framing; compare with balloon framing.

western hemlock A straight-grained, moder-
ately low-density softwood of the western US;
white to yellowish brown in color and not as
strong as Douglas fir; used for general construction
and plywood.

■western larch A moderately strong, heavy
softwood of the western US with coarse-tex-
tured reddish brown wood; used in general build-
ing construction, as timbers and flooring.

western red cedar A durable, straight-grained,
moderately low-density wood of the western US;
used extensively for construction where durability
is important, esp. for shingles and shakes. Also
called thuya.

Western Stick style A type of one-story
timber-framed house representing the finest of
the Craftsman style, developed in California
between about 1905 and the 1920s, exemplified
in the work of Greene and Greene, Architects,
who carried their architectural details to a high
art; compare with Stick style.

West Indian mahogany See carapa.

westwork At the west end of a Romanesque
church, a tower-like structure having a low
entrance hall; the room above it is open to the
nave.

wet-alarm valve A valve that (a) permits
the flow of water into a wet-pipe sprinkler sys-
tem, (b) prevents the reverse flow of water, and
(c) incorporates provisions for actuating an
alarm under specified flow conditions.

wet-bulb depression The difference between
dry-bulb and wet-bulb temperatures.

wet-bulb temperature The temperature of a
thermometer in which the bulb is enclosed in a
wick that is kept moistened.

wet-bulb thermometer In a psychrometer,
the thermometer whose bulb is kept moistened.

wet cleaning In the removal of asbestos, the
process of eliminating asbestos contamination
by using mops, cloths, and other cleaning tools
which have been wetted; these items are then
disposed of as asbestos-contaminated waste.

wet construction Any construction, e.g., a
wall, using materials (such as concrete, mortar,
plaster, etc.) which are installed or applied in
other than a dry condition.

■wet glazing A method of sealing glass in a
frame by the use of a glazing compound or
sealant which is applied with a knife or gun.

■wet hide Same as hiding power of a paint.

■wet mix Concrete containing a high propor-
tion of water, as evidenced by its runny consis-
tency when still in the unhardened state.

wet-mix shotcrete A shotcrete in which all
the ingredients (including water) are mixed
before they are fed into the delivery hose.

wet-on-wet painting A technique of spray
painting a second coat before the previous coat
has dried.

wet-pipe sprinkler system A fire sprinkler
system consisting of a network of pipes con-
taining water under pressure. Automatic
sprinklers are connected to piping so that each
sprinkler (head) protects an assigned area of
coverage; the water discharges immediately
from any sprinkler opened by the heat of a
fire.

wet riser A wet standpipe.

■wet rot The decay of timber having a high mois-
ture content, as a result of the attack of fungi.

wet screening, wet sieving Screening to
remove from fresh concrete, in the plastic state,
all aggregate particles larger than a certain size.

wet sieving See wet screening.

wet sprinkler system Same as wet-pipe sprin-
kler system.

wet stable consistency The consistency of
cement grout or mortar at which it contains the
maximum water without sloughing.

1067

wet standpipe system

wet standpipe system A standpipe system

completely filled with water at a pressure required
for immediate discharge and use.

wet storage stain Same as white rust.

■wet strength The strength of an adhesive joint
determined immediately after removal from a
liquid in which it has been immersed.

wet system See wet-pipe sprinkler system.

■wetting In soldering or brazing, the spreading of
a liquid filler metal or flux on a solid base metal.

■wetting agent A substance capable of lowering
the surface tension of liquids, facilitating the
wetting of solid surfaces, and permitting the
penetration of liquids into the capillaries.

■wet trades Those building trades which use dry
building materials that are mixed with water; for
example concrete, mortar, and plaster.

■wet-use adhesive In glue-laminated timber,
adhesives which perform satisfactorily under a
wide variety of conditions including exposure to
the weather, dry use, marine use, and pressure
treatment.

■wet vent A pipe, usually oversized, which func-
tions both as a fixture branch and as a vent, e.g.,
a soil or waste pipe that also serves as a vent.

wet wall See wet construction.

WF Abbr. for "wide flange."

WG Abbr. for "wire gauge."

WH Abbr. for water heater.

whaleback roof l.Same as ship's bottom roof.
2. Same as compass roof. 3. Same as rainbow roof.

■whale house In the early 18th century, a simple
house especially favored by whalers of Massachu-
setts. At the rear of the house there was a kitchen
with a small bedroom on each side. The kitchen
fireplace was usually on the opposite side of the
principal fireplace in the hall, 1 of the dwelling.

whaler See wale.

wheat-threshing barn See bank barn.

wheelbarrow A handcart usually fitted with
one wheel in front and two supporting legs in
back; and with two handles; used for transport-
ing materials over short distances.

wheelchair accessible A term sometimes
used in place of accessible, with regard to meet-
ing the requirements of the Americans with
Disabilities Act, in situations where the facilities
do not meet the accessibility requirements of all
aspects of the Act.

avatory

WASTE"

examples of wet vents

wheel ditcher Same as wheel trencher.
wheeler Same as winder.

wheelhouse A circular structure containing a
horse-driven threshing machine for wheat; often
attached to a barn.

wheeling step Same as winder.

wheel step, wheeling step A winder.

■wheel tracery Tracery radiating from a center,
as the spokes of a wheel.

■wheel window A large circular window on
which the radiation of tracery from the center is
suggested; a variety of rose window; a Catherine
wheel window.

■whetstone A piece of stone, natural or artifi-
cial, used to sharpen cutting tools.

Whipple truss A double-intersection Pratt
truss; has diagonal tension members and vertical
compression members.

whirley crane A large crane which can revolve
360°.

1068

wide-flange beam

wheel window

whispering gallery, whispering dome A

large dome or vault that reflects sounds (esp. high
frequencies) along a large concave surface so that
even whispers may be heard some distance away.

■white cement A pure calcite limestone cement,
similar in properties to ordinary cement, but
ground finer and of higher grade.

■white coat A gauged lime-putty, troweled,
plaster finish coat.

white deal, white fir See spruce.

white lauan See Philippine mahogany.

■white lead Basic lead carbonate, used as a
white opaque pigment in exterior house paints;
also used in ceramics and putty; available either
as a dry powder or as a mixture of turpentine and
linseed oil in paste form.

white lead putty A high-quality putty con-
taining at least 10% white lead mixed with cal-
cium carbonate and linseed oil.

white lime l.Same as high-calcium lime.
2. Same as pure lime.

white mahogany See avodire.

whitening In the grain of finished wood, a
white appearance, usually due to improper finish-
ing techniques or spotty adhesion of the coating.

■white noise Noise having a flat spectrum over
the frequency range of interest; the acoustic
power per unit-frequency is substantially inde-
pendent of frequency.

■white oak A hard, heavy, durable wood, gray to
reddish brown in color; esp. used for flooring,
paneling, and trim.

■white pine A soft, light wood; works easily; does
not split when nailed; does not swell or warp
appreciably; widely used in building construction.

white portland cement A portland cement,

produced from raw materials low in iron, which
hydrates to a white paste; used to yield a con-
crete of considerable whiteness.
whiteprint A reproduction of a construction
drawing in which black lines appear on a white
background. Compare with blueprint.

■white rot A type of decay in wood caused by a
fungus that leaves a white residue.

■white rust White corrosion products (such as
zinc oxide) on zinc-coated articles.

white spirit Petroleum ether, distilled from
crude oil; used as a solvent, esp. in varnishes.

white spots See water spotting.

white walnut See butternut.

■whitewash An impermanent coating applied
with a brush on walls to give them a white appear-
ance; usually a mixture of hydrated lime and
water; once typically consisted of a mixture of
ground-up chalk (whiting), lime, flour, glue, and
water, sometimes with addition of tallow or soap.

whitewood Same as tulipwood, 1.

■whiting Calcium carbonate pigment; used as an
extender in paint, in putty, and in whitewash.

whole-brick wall A brick wall, the thickness
of which is equal to the length of one brick.

■whole pitch The pitch of a gable roof whose
vertical rise is equal to the span.

whole timber A squared timber; a balk.

WHSE On drawings, abbr. for warehouse.

WI l.On drawings, abbr. for wrought iron.
2. On drawings, abbr. for "water inlet."

■wicket A small door or gate, esp. one forming
part of a larger one.

wicking The action of absorption by means of
capillary action.

wickiup Same as wikiup.

wide-flange beam A structural beam of rolled
steel or concrete having a shape whose cross sec-
tion resembles the letter H; has wider flanges
than an I-beam.

1069

wide-ringed

wide-ringed, coarse-grained, open-grained

Descriptive of wood having wide annual rings,
due to rapid growth; in softwood, usually weaker
than narrow-ringed wood.

wide-throw hinge A rectangular hinge with
extra-wide leaves for clearance.

■wide tolerance A tolerance greater than stan-
dard tolerance.

widow's walk A flat roof deck or raised obser-
vation platform sometimes having a view of the
sea, situated on the roof of a house and enclosed
by a balustrade or railing; the horizontal roof sur-
face is usually formed by truncating the top of a
hipped roof; also called a captain's walk.

wiggle nail A corrugated fastener.

wiggling-in See range-in.

wigwam An Indian dwelling in the American
Northeast, found in a variety of shapes; com-
monly, a domed structure having a framework of
saplings set into the ground, bent over, and
bound together. This framework was covered
with a watertight surface of overlapping matting
or animal skins. A hole at the top of the wigwam
provided an escape for smoke from the firepit
below; an opening at the side served as an
entrance. Compare with tipi.

wikiup A relatively small, temporary, round
dwelling of the Apache Indians of the American
Southwest; could be reassembled relatively eas-
ily and quickly; had a lightweight framework
formed by saplings lashed together at their tops
so as to form either a domed structure or a coni-
cal structure. Additional poles were placed along
the sides of the framework to provide added
structural strength; the framework was covered
with a matting.

■will The word will is used in connection with
acts and actions required of the owner or of the
architect/engineer; it is used by the owner or pur-
chaser as a self-imposed requirement; denotes the
information the owner will supply, documents
the owner will review, and approvals the owner
will issue — all at the proper time.

Williot diagram A graphical method of deter-
mining the deflections of a framed structure
under load.

Wilton carpet A velvet cut-pile carpet, wo-
ven with loops on a Jacquard loom, usually
having excellent wearing qualities.

winch A machine for pulling or lifting heavy
weights. It has a rotating drum around which a
pulling line or rope is turned; a hoist, 2.

■wind 1. British term for twist. 2. A once-used
synonym for warped or wined.

■windage loss A loss of fine droplets of water
which are entrained by circulating air; this loss of
water in a system (e.g., in the cooling tower of an
air-conditioning system) is replaced by makeup
water; usually expressed as a percentage of the
circulation rate.

wind beam A collar beam.

■wind box A plenum from which air for com-
bustion is supplied to a stoker, gas burner, or oil
burner.

■wind brace Any brace, such as a strut, which
strengthens a structure or framework against the
wind; usually a brace between a principal rafter
and a purlin to provide the roof framing with
greater rigidity.

wind brace

■windbreak A dense growth of trees, fence, wall
or the like, which provides protection against
the wind, esp. to gardens and buildings.

wind catcher Same as wind scoop.

wind-cut tree A tree shaped by the force of a
strong wind.

winder, wheel step A step, more or less
wedge-shaped, with its tread wider at one end
than the other, as in a spiral stair.

wind filling Same as beam fill.

wind force Same as wind load.

■wind guard 1. Any construction which pro-
vides protection against the wind, as a chimney
cap, 2. 2. Same as draft Met. 3. A draft bead.

winding-drum machine On elevators, a
gear-driven machine having a drum to which

1070

window

the wire ropes that hoist the car are fastened,
and on which they wind.

winding stair 1. Any stair constructed chiefly
or entirely of winders. 2. See screw stair.

winding strips, winding sticks Two short
sticks or strips of wood having parallel edges,
placed on a surface to test it for flatness.

windlass A modification of the wheel and axle
used for lifting weights; usually an axle, turned
by a crank, and a rope or chain wound around
the axle for raising the weight.

wind load The total force exerted by the wind
on a structure or part of a structure.

windmill A large machine in which the wind
acts on a number of vanes or blades, rotating them
about an axis, thereby producing mechanical
power; once widely used for grinding grain, sawing
timber, and pumping water. The earliest windmills
in America (similar to those in the Netherlands)
had four very large, slowly moving blades that
were cloth-covered, and required the constant
attendance of an operator. In 1854, a patent was
issued for an entirely new type of windmill, having
a large number of small blades, which was self-
regulating and could operate without human
intervention; this feature greatly increased its
practical application, especially for pumping
water. In the latter part of the 20th century, large
two-bladed windmills have been assembled in
large groups called "farms" for the environment-
friendly generation of electrical power.

window An opening, generally in an external
wall of a building, to admit light and provide ven-
tilation; usually glazed. The framework in which
the glass is set is called a sash; a flat sheet of glass,
cut to fit a window, or part of a window, is called a
pane. Many early glazed openings had fixed lights

HEAD JAMB

CASING

STOOL

APRON

windo

details

(i.e., could not be opened); others were a combi-
nation of fixed lights and a casement window that
opened outward. For various types of windows,
see angled bay window, art window, awning win-
dow, band window, bay window, blank window,
bow window, bull's-eye window, camber window,

1071

window apron

cant-bay window, cantilevered window, cant
window, casement window, Chicago window,
circle-head window, circular window, clerestory
window, compass window, cottage window, cross
window, dead window, diamond window, Dioclet-
ian window, dormant window, dormer window,
double-hung window, double-lancet window, drop-
head window, D-window, eyebrow window, false
window, fanlight, flank window, French window,
frieze-band window, frieze window, gable win-
dow, hopper window, jalousie, jib window, lancet
window, landscape window, lattice window,
leaded window, leper's squint, louver window,
low-side window, lucarne, lucome window,
Lutheran window, lynchnoscope, marigold win-
dow, oculus, oeil-de-boeuf, operable window,
oriel, oval window, Palladian window, peak-head
window, picture window, pivot window, pocket-
head window, reversible window, ribbon win-
dow, rose window, round-topped window, sash
window, semicircular window, serliana window,
single-hung window, skylight, sliding window,
sliphead window, square-headed window, sta-
tionary window, stepped windows, storm win-
dow, three-part window, transom window, trellis
window, tripartite window, triple-hung window,
Venetian window, wheel window, Yorkshire
light.

window apron A plain or molded wood strip
which covers the edge of the plastering below a
window stool.

■window back The inside face of the portion of
wall between the windowsill and the floor
below.

window band Same as ribbon window.

window bar 1. A muntin. 2. A glazing bar. 3.
A bar which prevents ingress or egress through a
window. 4. A bar for securing a casement or win-
dow shutters.

window bay A bay window.

window bead See inside stop, draft bead.

window blind A shade, blind, shade screen, or
shutter, 1 for a window.

window board Same as window stool.

■window bole A small, nonglazed wall open-
ing, usually shuttered, to let in light and air.

window box Same as weight box.

window casing The finished frame surround-
ing a window; the visible frame.

■window catch A fastening device, fixed to a
window sash, to prevent it from being opened
from the outside.

window-cill Same as windowsill.

window cleaner's anchor A fitting attached
securely to the outside of a window frame (or to
the wall just outside the frame) to which a win-
dow cleaner fastens a safety belt.

window cleaner's platform A platform oper-
ated manually or by power and suspended by
cables or ropes from roof assemblies; used to sup-
port window cleaners and maintenance personnel.

window configuration The shape, number,
and relationship of glass lights, mullions,
mutins, tracery, and/or window frames; also see
fenestration.

window crown The upper termination of a
window, such as a pediment; often decorative.

example of a window crown

window divider See mullion and muntin.

window dressing The trim, 2, usually of wood
or stone, around a window.

window frame The fixed, nonoperable frame
of a window designed to receive and hold the
sash or casement and all necessary hardware.

window furniture Same as window hardware.

window glass, sheet glass A soda-lime-silica
glass; in the US fabricated in continuous flat
sheets up to 6 ft (1.83 m) wide, in thicknesses
from 0.05 to 0.22 in. (1.27 to 5.59 mm); graded
AA, A, and B according to quality, but the
actual quality depends on the manufacturer.

window glazing bar Same as muntin.

window guard 1 . A window bar, 2 . 2 . A metal
protective grille, often of elaborate, decorative
character.

window hardware Devices, fittings, or mech-
anisms for opening, closing, supporting, holding

1072

window unit

open, or locking the sashes, including such items
as catches, chains, cords, fasteners, hinges, lifts,
locks, pivots, pulls, pulleys, sash balances, sash
weights, and stays.

window head The upper horizontal cross
member of a window frame.

window jack Same as builder's jack.

window jack scaffold A scaffold the plat-
form of which is supported by a bracket or jack
which projects through a window opening.

■window lead A slender bar or rod of lead, cast
with grooves to receive the glass in a window.

window ledge Same as windowsill.

window lift, sash lift A handle, or the like,
secured to a sliding sash (usually the lower rail)
to assist in raising or lowering it.

windowlight A pane, 1 of glass which has been
installed in a window; a windowpane.

window lining See lining.

window lock Same as sash lock.

windowpane In a window, a pane, 1.

window post In a framed building, one of the
solid uprights between which the window frame
is set, often two studs nailed together.

window pull Same as sash pull.

window sash See sash.

r STILE

BOTTOM RAIL

window schedule A tabulation, usually on a
blueprint or in specifications, which lists all win-
dows required on a construction job, indicating
the sizes, number of lights, types, locations, and
special requirements.

window screen l.See insect screen. 2. An
ornamental grille or lattice fitted into a window
opening.

window seat l.A seat built into the bottom
inside of a window. 2. A seat located at a window.

SASH
window sashes

window seat

window shutter See shutter, 1.

windowsill See sill, 3.

window space The total window area in a
room or building.

window spring bolt A spring bolt which fixes
a sash (which is not counterbalanced) in any
selected position.

window stile See pulley stile.

window stool, window board, elbow
board A horizontal board on a windowsill,
fitted against the bottom rail of the lower sash
and between the sash frame stiles; forms a base
on which the casing rests; usually of wood, but
may be of metal or other facing material.

window stop Same as sash stop.

window surround A decorative element or
structure on the exterior wall surface around a
window. (See illustration p . 1074.)

window trim The casing around a window;
the interior decorative finishing elements.

■window unit A complete window, with sashes
(ventilators, 2) or casements, ready for shipment
or installation in a building.

1073

window wall

vind'

window surround

window wall A type of curtain wall, usually
composed of vertical and horizontal metal framing
members containing fixed lights, operable win-
dows, or opaque panels, or a combination thereof.

window weight See sash weight.

■window 'well The clear space created by a soil-
retaining structure located immediately below a
window whose sill height is lower than the adja-
cent ground level.

window yoke A window head which ties
together the pulley stiles.

■wind pressure The pressure on a surface pro-
duced by the wind blowing against it.

windproof Same as windtight.

wind scoop, wind catcher A device, espe-
cially found in hot regions of the Middle East,
that ventilates a house by the use of wind. A
small tower on the roof contains an opening that
faces the prevailing wind, which is at a cooler
temperature than the interior of the house.
Because the wind velocity at this opening is
greater than it is at the lower windows of the
house, air in the shaft of the tower is forced
down the shaft to cool the house.

■wind shake A crack or fissure in timber
caused, during growth, by wind strain.

wind-speed rating The highest wind speed
that a wall is capable of withstanding.

wind stop 1 . A weather strip used around a
door or window. 2. A strip, usually of wood or
metal, covering the joint between a sash or case-
ment and the adjacent stile. 3. A wood or metal
strip covering a crack of any type in a building to
prevent wind from blowing in.

■windtight Descriptive of construction in which
all openings and cracks have been carefully
sealed, using weather strips.

■wind uplift A negative force (i.e., an upward
pull) which acts on a roof because of wind.

wine cellar, wine vault A storage room for
wine, usually underground so as to be cool and
dark.

■wing l.A subsidiary part of a building
extending out from the main portion. 2. In a
theater, the offstage space at the side of the
acting area. 3. One of the four leaves of a
revolving door.

wing balcony That part of a balcony which
extends along the sidewalls of an auditorium,
toward the stage.

wing compass A compass having an arc-
shaped piece (which is attached to one leg)
which passes through the opposite leg and which
may be clamped with a set screw to a desired
opening.

wing dividers A pair of dividers, similar in
construction to a wing compass.

wind shake

wing dividers

■winged bull An Assyrian symbol of force and
domination, of frequent occurrence in ancient
Assyrian architectural sculpture; pairs of winged
human-headed bulls and lions of colossal size
usually guarded the portals of palaces.

■winged disk In Egyptian Revival architecture,
same as sun disk.

winglight See side light, 1 .

■wing nut A nut having projections so that it
can be tightened with one finger and the thumb.

1074

wire nut

winged bull

wing nut

■wing pile A bearing pile (usually of concrete)
which widens at the top.

■wing screw A screw having a wing-shaped head,
designed for manual turning without a driver or
wrench.

■wing wall A subordinate wall, one end of which
is built against an abutment; usually acts as sup-
port for the abutment and as a retaining wall.

■wiped joint A solder joint made by pouring
molten solder onto the joint, and then wiping
the joint with a cloth or with a small paddle so as
to shape the joint as required.

■wire cloth A stiff fabric of fine woven wire; used
in screens for excluding insects, in sieves, etc.; in
the US, the number of openings per square inch
is called the mesh.

wire comb, wire scratcher A tool for
scratching a plaster base coat in order to improve
the bond of the next coat.

wire-cut brick Clay that has been cut by wires
and then burnt in a kiln at an elevated tempera-
ture.

■wire duct Conduit or tubing used to encase
electrical wire or rope.

wired glass See wire glass.

■wire gauge 1. An instrument for measuring the
thickness of wire or sheet metal; usually consists of
a steel plate having a series of notches, of standard
opening sizes, around the edge. 2. One of several
systems for specifying the diameter of a wire.

wire gauze Wire cloth of fine texture.

wire glass, wired glass, safety glass Sheet
glass containing wire mesh embedded between
the two faces to prevent shattering in the event
of breakage.

wire height Same as carpet pile height.

■wire holder An electrical insulator having a
mounting screw or mounting bolt and a hole for
securing a conductor.

■wire lath Wire welded to form a netting, usually
with a paper backing; used as a base for plaster.

wire mesh See welded-wire fabric.

wire mesh partition Same as mesh partition.

■wire nail A nail made of wire, esp. a finishing
nail or the like.

Lead pipe

Brass pipe

Overlap _

wiped joint

Wiped solder
joint

■wire A filament or slender rod of drawn metal.
wire brad A brad, 1.

i: *■'.::

— ^LJ

«3

... u

FINISH

CASING

wire nails

wire nut A mechanical connector for wires
which are small in size; consists of an insulating
cap over a threaded or coiled metal insert; the
wires to be connected are stripped of insulation
at their ends and inserted in the wire nut; then

1075

wire rope

the wire nut is turned by hand until the wires are
securely joined.

■wire rope A rope usually fabricated of twisted
strands of wire, usually laid over a core.

■wire saw An assembly for sawing stone by a
rapidly moving continuous wire that carries a
slurry of sand or other abrasive material.

wire scratcher Same as wire comb.

■wire size In the US, a size, usually stated in
terms of American Wire Gauge (AWG) and/or
thousand circular mills (MCM) which applies to
copper conductors.

■wire tie Same as tie wire.

wireway Same as raceway.

wire wrapping A high-tensile wire which is
wound, under tension, around concrete tension-
resisting structural components, circular con-
crete walls, and the like.

wiring box In interior electric wiring, a box,
usually of metal, installed at each outlet, junc-
tion point, or switch (except for exposed wiring
on insulators); classified as a floor box, outlet
box, sectional switch box, or utility box.

wiring channel A metal housing; see, illustra-
tion for a fluorescent lamp.

■wiring device Any electrical device used to
control and to provide connection points for
low-voltage outlets, lighting systems, and appli-
ances (e.g., wall switches and receptacles).

■witch door A door whose lowest panels form a
capital letter X; once thought by some to ward
off evil spirits; compare with Christian door.

witch's hat 1 . A conical roof with an especially
steep slope. 2. Same as bonnet roof.

withdrawing room An obsolete term for
drawing room.

withe, wythe 1 . A partition dividing two flues
in the same chimney stack. 2. A flexible, slen-
der twig or branch; an osier; esp. used to tie
down thatching on roofs. 3. Each continuous

witch door

WITHE

FLUE

withe, 1

vertical section of wall, one masonry unit in
thickness.

with-the-bed cut Same as fleuri cut.

■witness corner A marker set on a property
line, near, but not on, a corner; used where it
would be impracticable or impossible to main-
tain a monument at the corner itself.

WK l.On drawings, abbr. for "week." 2. On
drawings, abbr. for "work."

W/O On drawings, abbr. for "without."

■wobble friction In prestressed concrete, the
friction caused by the unintended deviation of
the prestressing tendon from its specified profile.

wobble saw A drunken saw.

women's room See ladies' room.

■wood The hard fibrous substance which com-
poses the trunk and branches of a tree, lying
between the pith and bark.

■wood block 1 . One of many small, solid-wood
blocks having plane faces, set in mastic, usually
on a concrete floor slab, to form a durable floor

1076

wood joint

finish. 2. A solid piece of wood placed in a con-
crete formwork to prevent movement of the
formwork or to fill a space.

wood brick, fixing brick, nailing block

1. A piece of wood the size and shape of a brick;
inserted in brickwork to serve as a means of
attaching finishings, etc. 2. See nog.

wood-cement concrete A concrete mixture
using sawdust and small chips of wood as the
aggregate; finished as a relatively smooth surface
without visible voids.

wood chimney A chimney built of wood
boards or timbers and then plastered on its inte-
rior, usually with clay, to provide a measure of
fire protection. Because of its susceptibility to
ignite, its use had been limited to areas where
bricks and stone were not readily available. See
clay-and-sticks chimney.

wood chipboard See particleboard.

■wood chisel A tool having a flat cutting edge
with a long stiff handle; used to cut or remove
chips or strips of wood by striking the end of the
handle repeatedly with a hammer, or the like.

wood dough A synthetic wood, usually made
with wood fibers; used as a filler.

■wood failure In plywood, the area of wood
fiber remaining at the glueline following com-
pletion of a specified shear test.

wood-fibered plaster A mill-mixed gypsum
plaster containing wood fiber; used neat or with
one part of sand to one part of plaster, by weight,
for greater strength.

wood-fiber insulation Thermal insulation
made from wood fibers.

■wood- fiber slab A slab composed of a mixture
of excelsior and cement which is not tightly
compacted; used as a base for plaster, where good
thermal insulation is required.

■wood filler A liquid or paste composition used
to fill the pores of a wood surface before varnish-
ing or waxing.

wood finishing The planing, sanding, and
subsequent staining, varnishing, waxing, or
painting of a wood surface.

wood fire-retardant treatment The im-
pregnation of wood or wood products with a
fire-retardant chemical, under pressure, to reduce
their flammability or combustibility.

■wood flooring Flooring consisting of standard
dressed and matched boards.

■wood flour A finely ground, dried wood pow-
der; used in the molding of plastics, in plastic
wood, and as an extender in some glues.

wood form See form.

wood-frame construction Building con-
struction in which exterior walls, load-bearing
walls and partitions, floor and roof construc-
tions, and their supports, are all built of wood.
See balloon framing, iron framing, platform
framing, post-and-beam framing, post-and-girt
framing, western framing; also see timber-
framed building, timber-framed house. Compare
with steel-frame construction.

wood-framed house See timber-framed house.

woodgraining Same as false woodgraining.

wood-grain print A simulated wood-grain
pattern, applied with patterned rolls to various
wood-base substrates, such as hardboard and
low-grade plywood.

wood ground Same as ground, 1.

wood gutter A gutter, 1 along the eaves of a

roof, usually made of boards but sometimes made

of a solid piece of wood.

SHEATHING

wood gutter

■wood joint A joint formed by two boards, tim-
bers, or sheets of wood that are held together by
nails, fasteners, pegs, or the like. For specific types
of wood joints, see broken joint, butt joint, cogged
joint, dado joint, dovetail joint, extruded joint,
finger joint, half-dovetail, half-lap joint, hewn-
and-peg joint, housed joint, mortise-and-tenon

1077

woodland

joint, rabbet joint, scarf joint, shiplap joint, spalled
joint, spline joint, straight joint, tongue-and-
groove joint.

■woodland A tract of land dominated by trees
but often containing shrubs and other vegeta-
tion as well.

wood lath One of many thin narrow strips of
wood that serve as a base for plaster; usually
nailed at regular intervals to studs or to boards in
walls and ceilings. Until the early 19th century,
wood lath was hand-split from larger pieces of
wood; later, such strips were usually cut with cir-
cular saws, providing slats of relatively uniform
width and thickness. Wood lath as a base for plas-
ter in new construction has now been replaced in
most countries by expanded-metal lath.

wood moisture Same as moisture content, 1.

wood molding See WP-series molding pat-
tern.

wood mosaic l.See mosaic, 2. 2. See par-
quetry.

wood nog See nog.

wood oil l.See tung oil. 2. An oleoresin used
for caulking and waterproofing.

wood preservative A chemical used to pre-
vent or retard the decay of wood, esp. by fungi or
insects; widely used preservatives include cre-
osote, pitch, sodium fluoride, and tar; esp. used
on wood having contact with the ground.

wood rasp Same as rasp.

wood roll See roll, 1.

wood rosin See rosin.

wood screw A helically threaded metal fas-
tener having a pointed end; forms its own mat-
ing thread when driven into wood or other
resilient materials.

■wood shingle A thin roofing unit of wood, usu-
ally cut from green wood and then kiln-dried,
either split along the grain or cut to stock lengths,
widths, and thicknesses; used as an exterior cover-
ing on sloping roofs and on side walls and applied
in an overlapping fashion. Also see shingle.

wood sill See sill.

wood slip A wood ground, 1.

wood stud anchor, nailing anchor A

metal piece or clip which is attached to the
inside of a doorframe and secures the frame to a
wood stud partition.

wood treatment l.See fire-retardant wood.

2. Treatment with a wood preservative.
wood turning See turning.

wood turpentine, oil of turpentine A tur-
pentine made by the distillation of sawdust, wood
chips, and waste wood; except for its characteris-
tic odor, it differs little from true turpentine.

wood veneer Same as veneer, 1.

■wood window A wood or wood-clad frame,
with or without a ventilating sash, which accom-
modates glazing.

wood-wool See excelsior.

■wood-wool slab A rigid composition board,
fabricated of excelsior (wood-wool) and cement.

woodwork Work produced by the carpenter's
and joiner's art, generally applied to parts of
objects or structures in wood rather than the
complete structure.

woodworker's vise A vise, at the front edge
of a workbench, for holding a piece of wood
while it is being worked on; has jaws which are
flush with the bench surface.

woodworker's vise

■woolly grain The condition on the surface of a
timber resulting from a cutting operation in
which the wood fibers have been pulled to the
surface instead of being cut cleanly.

■work l.AU labor necessary to produce the con-
struction required by the contract documents, and
all materials and equipment incorporated or to be
incorporated in such construction. 2. The produce
of a force by its corresponding displacement.

workability l.That property of freshly mixed
concrete, plaster, or mortar which determines
the ease and homogeneity with which it can be
mixed, applied, compacted, spread, or finished;
placeability. 2. The degree of ease of cutting and
quality of cut that can be obtained in various
woods with hand tools or machines.

1078

woven valley

work edge, face edge, working edge In

carpentry, the first edge to be planed smooth;
the edge from which other edges are measured or
trued.

worked lumber Lumber that, in addition to
being dressed, has been matched, shiplapped, or
patterned.

■work end In carpentry, the first end to be
planed smooth.

■worker's hoist A hoisting and lowering mech-
anism equipped with a platform that moves in
guides in a substantially vertical direction; used
primarily for raising and lowering workers to var-
ious working levels when a building is under
construction.

work face, face side, working face In car-
pentry, the first surface to be planed smooth; the
surface from which the others are measured or
trued.

■workhouse l.An institution for confining
individuals sentenced to terms usually less than
one year. 2. (Brit.) A poorhouse.

■working The alternate swelling and shrinking
in seasoned wood, resulting from moisture con-
tent changes that occur with changes in relative
humidity of the surrounding air; also called
movement.

working drawings Drawings, intended for use
by a contractor, subcontractor, or fabricator,
which form part of the contract documents for a
building project; contain the necessary informa-
tion to manufacture or erect an object or structure.

working edge See work edge.

working face See work face.

■working life The period of time during which
a liquid resin or adhesive, after mixing with cat-
alyst, solvent, or other ingredients, remains
usable; pot life.

working load, service load The load, 1 which
a structure is expected to sustain and for which it
is designed; cannot exceed the allowable load.

working point On a construction drawing, a
point which is designated as a reference for other
points.

working rail See fly rail.

working stage A partially enclosed portion of
an assembly room or building, cut off from the
audience section by a proscenium wall, and
which is equipped with scenery loft, gridiron, fly

gallery, and lighting equipment; the minimum
depth from the proscenium curtain to the back
wall may be specified by code.

■working stress The maximum permissible
stress under actual working conditions.

working stress design A method of design in
which structures or members are proportioned
for prescribed working loads at stresses which are
well below their ultimate values; linear distribu-
tion of flexural stresses is assumed.

work light In the theater, a light used to pro-
vide illumination for rehearsing, scene shifting,
or other work onstage or backstage.

workmen's compensation insurance Insur-
ance covering liability of an employer to his em-
ployees for compensation and other benefits
required by workmen's compensation laws with
respect to injury, sickness, disease, or death arising
from their employment.

work order See notice to proceed.

work place That part of the usable floor area
of a building that is intended for an individual or
group of people to work in.

work plane The plane at which work is usually
done, at which the illumination is specified and
measured; usually assumed to be a horizontal
plane about 30 in. (76 cm) above the floor.

works British term for factory.

■workshop A building or room used for handi-
craft work.

■work station A space in a building, all or part
of a work place, where an assigned task is per-
formed; such spaces are often created by parti-
tions or by the arrangement of furniture or
equipment on the floor.

worm fence Same as zigzag fence.

wormhole, bore hole A hole or tunnel of
any size in wood caused by worms.

■wound paint A type of paint used to cover
extensive wounds to a tree, especially after it
has been damaged by a storm or following
pruning.

woven board See interlaced fencing.

■woven carpet A carpet which is constructed on
a loom by interlacing the carpet warp and filling
threads, e.g., Axminster, velvet, or Wilton carpet.

woven fencing See interwoven fencing.

woven valley See laced valley.

1079

woven-wire fabric

woven-wire fabric A prefabricated steel rein-
forcement for reinforced concrete; composed of
cold-drawn steel wires mechanically twisted
together to form hexagonally shaped openings.

woven-wire reinforcement See welded-
wire fabric.

WP 1. On drawings, abbr. for waterproof. 2. On
drawings, abbr. for "weatherproof."

WP-series molding pattern One of a large
number of profiles of commercially available
moldings listed by the Western Wood Products
Association.

■wrack l.The lowest grade of softwood. 2. A
cull.

wraparound astragal See overlapping astra-
gal.

wraparound frame Same as keyed-in frame.

wraparound porch A full-width porch that
continues around the sides of a house.

■wreath 1 . The curved portion of the string or
handrail which follows a turn in a geometrical
stair, usually a quarter circle, and therefore cor-
responds to a portion of the surface of a vertical
cylinder; also called a wreath piece. 2. A
twisted band, garland, or chaplet, representing
flowers, fruits, leaves, etc.; often used in deco-
ration.

wreathed column A column entwined by a
band which presents a twisted or spiral appearance.

wreathed stair Same as geometrical stair.
wreathed string See wreath, 1.

■wreath piece A curved section of a stair string;

a wreath, 1 .
■wrecking The act of demolishing or razing a

structure.
wrecking ball, skull cracker A heavy steel

ball used in structural demolition; usually swung

or dropped from a crane or derrick.
wrecking bar See pinch bar.

wrecking bar

wrecking strip A small piece or panel which is
fitted into a concrete formwork assembly in such
a way that it can be removed easily, ahead of the
main panels or forms, thereby making it easier to
strip those major form components.

■wrench A hand tool consisting of a metal han-
dle with a jaw at one end which is designed to fit
the head of a bolt or nut (or to grasp a pipe or
rod) so that it may be turned.

Wrightian An imprecise term suggestive of the
work of Frank Lloyd Wright (1867-1959) and
some of his followers. Wright cannot be charac-
terized by a single architectural style; for example,

-3&

wreathed column

Wrightian: Glasner House, Glencoe, IL,
designed by Frank Lloyd Wright

1080

wye (Y) connection

some of his early buildings, closely associated
with the Prairie School, differ markedly from his
later designs. Also see Organic architecture and
Prairie style.
wrinkling, crinkling, riveling 1. The dis-
tortion in a paint film appearing as ripples;
may be produced intentionally as a decorative
effect or may be a defect caused by drying con-
ditions or an excessively thick film. 2. The
crinkling of the surface skin of a sealant;
affects its appearance, but usually not its seal-
ing capability.

wrist control The control of the flow of water
from a faucet into a sink by pressure of a wrist
against a lever; widely used in hospitals.

wrot lumber British term for dressed lumber.

■wrought Said of an object that has been shaped
by beating with a hammer.

■wrought iron A commercially pure iron of
fibrous nature; valued for its corrosion resistance
and ductility; used for water pipes, water tank
plates, rivets, stay bolts, and forged work.

wrought-iron work Iron that is hammered or
forged into shape, either when the metal is hot
or cold; often decorative.

wrought lumber British term for dressed
lumber.

wrought nail A nail individually wrought by
hand, often with a head forged into a decorative
pattern; no longer in use.

wrt Abbr. for "wrought."

WS On drawings, abbr. for weather strip.

wt., Wt. Abbr. for "weight."

WT Abbr. for "watertight."

W-truss A truss whose upper and lower chords
are joined by web members having the shape of
the letter W.

WEB
MEMBER

GUSSET

UPPER
CHORD

WVT Abbr. for "water vapor transmission."
WW Abbr. for "warm white."
WWX Abbr. for "warm white deluxe."
wye 1 . A Y-branch. 2 . A Y-fitting.
wye branch See Y-branch.

wye ( Y ) connection 1 . A method of connect-
ing the ends of the windings of a poly-phase
transformer; each of the three windings are
joined at a common point; the other ends of the
windings provide the line-to-line voltages. Com-
pare with delta connection. 2. A fire department
connection with two inlets; a Siamese connec-
tion.

wye connection, 1

LOWER CHORD

W-truss

wye connection, 2

1081

wye fitting

wye fitting See Y-fitting.

■wye level A surveyor's leveling instrument
having a telescope and attached spirit level,
mounted in Y-shaped supports which permit it
to be lifted and reversed, end for end; it is used in
the direct measurement of differences in eleva-
tion.

wye tracery See y-tracery.

wythe See withe.

wye level

1082

XBAR On drawings, abbr. for "crossbar."

X»brace, cross brace Any braces which cross
each other to form the letter X.

X»bracirig See cross bracing, 1.

XCU In insurance terminology, letters which
refer to exclusions from coverage for property
damage liability arising out of explosion or blast-
ing (designated by X), collapse or structural
damage to any building or structure (designated
by C), and underground damage caused and
occurring during the use of mechanical equip-
ment (designated by U).

xenodocheum In classical architecture, a
room or building devoted to the reception and
accommodation of strangers or guests.

xenon lamp A lamp bulb, containing a gas
called xenon, which emits light similar to day-
light when excited by an arc discharge.

X HVY On drawings, abbr. for "extra heavy."

XL Abbr. for "extra large."

X»mark See face mark.

XSECT On drawings, abbr. for cross section.

X STR On drawings, abbr. for "extra strong."

XXH On drawings, abbr. for "double extra heavy."

xylol A colorless aromatic hydrocarbon liquid;
used as a solvent for paints and varnishes.

xyst, xystum l.In classical architecture, a
roofed colonnade for exercise in bad weather. 2.
In ancient Rome, a long, tree-shaded prome-
nade. 3. A tree-lined walk.

xyst, 1

1083

This page intentionally left blank

Yale lock A proprietary name for a cylindrical
lock.

Yankee barn A steeply pitched, timber-
framed, side -gabled wood barn of post-and-lintel
construction, often with a gambrel roof; usually
having no forebay; typically built against a hill-
side with animals housed at ground level on the
lower side adjacent to the barn; similar to a bank
barn.

Yankee gutter Same as arris gutter.

yard That part of a building plot not occupied
by the building, open to the sky.

yardage 1 . The number of cubic yards exca-
vated or filled. 2. An area or surface, expressed
in square yards.

yard drain A surface drain; used to clear an
open area of surface water.

yard line That section of a consumer's gas pip-
ing and fittings that extends from the point of
service, 3 (i.e., point of delivery) to the house
piping.

yard lumber Lumber up to 5 in. (12.5 cm)
thick intended for general building construc-
tion.

yarn count See carpet face weight.

Y-branch, wye branch In a plumbing sys-
tem, a branch in the shape of the letter Y.

REGULAR

REDUCING

Y-branch

Y»connection See wye (Y) connection.

yd Abbr. for "yard."

year ring Same as annual ring.

yellow fir See Douglas fir.

yellowing The development of a yellow color

or cast in white or clear coatings after aging.
yellow metal Same as Muntz metal.
yellow ocher, yellow ochre A form of earth

used as a yellow pigment; limonite.

yellow pine A hard resinous wood of the
longleaf pine tree, having dark bands of summer-
wood alternating with lighter-colored springwood;
used as flooring and in general construction.

yellow poplar, poplar A moderately low-
density, even-textured hardwood of the central
and southern US; color varies from white to
yellow, tan, or greenish brown; used for veneer,
plywood, and lumber core for cabinetwork.

yellow poplar Same as tulipwood, 1.

yelm A bundle of reeds or combed straw used as
thatching material for a roof.

yett A term for a massive gate, such as a
portcullis, chiefly used in Scotland.

Y-fitting, wye fitting A pipe fitting, 1, one
end of which subdivides, forming two openings
at an angle, usually 45° to the run of pipe.

yield l.The volume of freshly mixed concrete
produced from a known quantity of ingredients;
volume yield. 2. The number of product units,
such as blocks, produced per bag of cement or
per batch of concrete.

yield point The lowest stress in a material (less
than the maximum attainable stress) at which
the material begins to exhibit plastic properties;
beyond this point an increase in strain occurs
without an increase in stress.

yield strain The level of strain at which steel
starts to show substantial plastic deformation.

yield strength The stress at which a material
exhibits a specified limiting deviation from the
proportionality of stress to strain.

1085

Y4evel

Y»level Same as wye level.

yoke 1 . A horizontal framework around the
formwork for a column. 2. The horizontal piece
forming the head of a window or door frame.
3. In plumbing, a two-way coupling for pipes, in
the shape of the letter Y. 4. A yoke vent.

PANELS

WEDGE

BOLT

YOKE
YOKE

Vent stack-

Branch vent / 1 — |

Yoke relief vent-

Branch drat

Soil or waste stack-

]

yoke, 1

yoke relief vent, 2

yoke relief vent, yoke vent See yoke vent,

2. 1. A pipe connecting upward from a soil stack
or waste stack to a vent stack for the purpose of
preventing pressure changes in the stack. 2. A
vertical or 45° relief vent of the continuous-
waste-and-vent type formed by the extension of
an upright wye branch or 45° wye branch inlet
of the horizontal branch to the stack; becomes a
dual yoke vent when two horizontal branches
are thus vented by the same relief vent. 3. A
vent connected to a soil or waste stack that

VENT STACK

yoke vent, 2

continues upward to the connection with the
vent stack for the purpose of reducing pressure
changes in the stack.

Yorkshire bond Same as monk bond.

Yorkshire light A window having one or more
fixed sashes and a movable sash which slides
horizontally.

Young's modulus In an elastic material
which has been subject to strain below its elastic
limit, the ratio of the tensile stress to the corre-
sponding tensile strain.

YP On drawings, abbr. for yield point.

YR On drawings, abbr. for "year."

YS On drawings, abbr. for yield strength.

Y»tracery A type of tracery in which the mul-
lions split in the shape of the letter Y

yurt A circular tent-like dwelling used in
northern Asia; can be readily dismantled,
moved, and reassembled at another site; pri-
marily constructed of a felt-like material
and/or skins that are stretched over a wood
framework.

1086

zaguan l.In Spanish architecture and deriva-
tives, an entry; often a massive wooden gate that
was often sheltered and wide enough to permit
large wagons or coaches to enter the courtyard
(placita) of a casa del rancho. Often had a small
door adjacent to, or a door set within the zaguan,
for pedestrian traffic. 2. In ecclesiastical His-
panic architecture, a corridor between a cloister
and its exterior.

& <3 Q — Q Q_

zaguan

zambullo door In early Spanish Colonial
architecture, especially in New Mexico, a wood
door hung on wood pintle hinges.

zapata In Spanish Colonial architecture of the
Americas, a horizontal piece of wood, atop a
post, that provides greater bearing area to sup-

| ^-yi^L^p,

port the load imposed on the post from above;
usually carved; similar to a bolster, 1 but often
more highly decorative.

Zapotec architecture An eclectic archi-
tecture of Mesoamerica, especially in Oaxaca,
Mexico. Characterized by multiterraced pyramids
ascended by broad stairways, accented by wide
balustrades and tablets, the use of circular sup-
porting columns, and free-standing structures
placed around a large plaza.

zax Same as sax.

Z»bar In a suspended acoustical ceiling, one
form of main runner.

Z-braced battened door A battened door
held together by two horizontal boards that are
joined by a diagonal board; suggestive of the
letter Z.

zebrawood, zebrano A moderately hard and
heavy wood, pale yellow or pinkish brown, hav-
ing pronounced dark stripes; found in central
and western Africa. Used for plywood and deco-
rative applications.

zee A metal member having a modified Z-
shaped cross section; the internal angles of the Z
are approximately equal to right angles.

zapata

zeolite A coarse-grained chemical compound
used in water-softening equipment; consists of a
greenish granular material containing iron (up
to 25%), a large percentage of silica, and some
alumina and potash.

zeolite softening A water softening process
now called cation-exchange softening.

1087

zero-slump concrete

zero-slump concrete Said of freshly-mixed
concrete which has no measurable slump; com-
pare with no-slump concrete.

zeta l.A closed or small chamber. 2. A room
over a porch of an early Christian church, where
the porter or sexton lived and where documents
were kept.

ziggurat A Mesopotamian temple tower; from
the end of the 3rd millennium B.C. on, ziggurats
rose in three to seven stages, diminishing in area
and often in height square (Sumer) or rect-
angular (Assyria), built of mud brick and faced
with baked brick laid in bitumen.

zigzag, dancette An ornamental molding of
continued chevrons.

zigzag bond Same as or similar to herringbone
bond.

zigzag fence A fence constructed of split rails
that (in plan) alternate in direction, usually at
a wide angle of about 120 degrees. At the inter-
section between the two stacks of rails, uprights
are sometimes driven in the ground and lashed
to the fence to improve its stability.

Zigzag Moderne See Art Moderne.

zigzag molding, dancette An ornamental mold-
ing of continued chevrons. Also see reversed
zigzag molding.

types of zigzag moldings

zigzag riveting Same as staggered riveting.

zigzag rule A folding rule whose sections are
pivoted; stiff when fully opened.

zinc A hard bluish white metal, brittle at nor-
mal temperatures, very malleable and ductile
when heated; not subject to corrosion; used for
galvanizing sheet steel and iron, in various
metal alloys, and as an oxide for white paint
pigment.

zinc chromate, buttercup yellow, zinc yel-
low A bright yellow stable pigment used in
paints, esp. in metal primers as a rust-inhibiting
pigment.

zinc coating See galvanizing.

zinc dust A fine gray powder of zinc metal usu-
ally of at least 97% purity; used as a pigment in
paint primer for galvanized iron and other metal
substrates.

zinc oxide, zinc white A white water-insolu-
ble pigment which has low hiding power; used in
paints to provide durability, color retention, and
hardness, and to increase sag resistance.

zinc white See zinc oxide.
zinc yellow See zinc chromate.

zocco Same as socle.

zone l.In an air-conditioning or heating sys-
tem, a space (or group of spaces), served by the
system, whose temperature (or humidity) is reg-
ulated by a single control. 2. A vertical or hori-
zontal subdivision of a water supply system,
sprinkler system, or standpipe system. 3. See
pressure zone.

zoned heating Heating or cooling in one area
of a building which is completely independent of
the control of the heating in other areas of the
building.

zone of saturation The level below which the
subsoil and rock masses of the earth are fully sat-
urated. See illustration under groundwater.

zoning The control by a municipality of the
use of land and buildings, the height and bulk
of buildings, the density of population, the
relation of a lot's building coverage to open
space, the size and location of yards and
setbacks, and the provision of any ancil-
lary facilities such as parking. Zoning, estab-
lished through the adoption of a municipal

1088

zwinger

ordinance, is a principal instrument in imple-
menting a master plan.

zoning ordinance A regulation that governs
the location and use of land and buildings in a
specific area.

zoning permit A permit, issued by the appro-
priate governing agency, which authorizes land
to be used for specific purposes.

zoological garden A park, often quite large,
designed for exhibiting wild animals.

zoomorph An image or symbol of some repre-
sentation of an animal.

zoophoric column A column bearing a figure
or figures of one or more men or animals.

zoophorus A horizontal band bearing carved
figures of animals or persons, esp. the Ionic frieze
when sculptured.

zotheca In Near Eastern architecture and
derivatives, an alcove off a living room.

zwinger The protective fortress of a city.

1089

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